Steel Sheet, Method Of Manufacturing Tailored Blank And Method Of Manufacturing Steel Pipe
Abstract:
A steel sheet comprising: a first plated section in which an intermetallic compound layer and an aluminum plated layer are provided on the surface of a base material steel sheet, in this order from the base material steel sheet side; a first exposed section in which the base material steel sheet is exposed; and a second plated section in which an intermetallic compound layer and an aluminum plated layer are provided on the surface of a base material steel sheet, in this order from the base material steel sheet side. In a first direction perpendicular to the thickness direction of the steel sheet and running from the first plated section toward one end edge of the steel sheet, the first plated section, the first exposed section, the second plated section, and the end edge of the steel sheet are arranged in this order on one surface of the base material steel sheet, and on the other surface of the base material steel sheet at least the first plated section, the first exposed section, and the end edge of the steel sheet are arranged in this order in the first direction. When viewed from a cross section parallel to both the first direction and the thickness direction of the steel sheet, the second plated section is provided from the boundary of the first exposed section and the second plated section to a low region of the surface of the base material steel sheet, said low region being located closer to the interior of the base material steel sheet, in the thickness direction, than an imaginary line extending in the first direction.
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Notices, Deadlines & Correspondence
6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
Inventors
1. FUJIMOTO Hiroki
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
2. YASUYAMA Masanori
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
3. TATSUMI Yujiro
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
4. FUKUCHI Hiroshi
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
5. KOBAYASHI Shintaro
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
6. FUJITA Soshi
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
7. ZENIYA Tasuku
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
8. SUZUKI Yuki
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
9. ISHIDA Yoshinari
c/o NIPPON STEEL CORPORATION, 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo
1008071
Specification
The present invention relates to a steel plate, a tailored blank, a hot press molded product, a steel pipe, a hollow hardened molded product, a steel plate manufacturing method, a tailored blank manufacturing method, a hot press molded product manufacturing method, a steel pipe manufacturing method, and a hollow. The present invention relates to a method for producing a state-quenched molded product
The joint static strength (hereinafter referred to as static strength) was calculated by dividing the load by the tensile strength x the cross-sectional area on the side where the base metal plate thickness is small.
Fatigue strength test (referred to as fatigue limit) uses an electromagnetic resonant fatigue strength testing machine, the tensile load control axial force fully pulsating in air at room temperature, stress ratio 0.1, the stress repetition count 10 7 times, about repetition rate The test conditions were 80 Hz. These results are shown in Table 5.
[0179]
(Corrosion resistance test after painting) After
chemical conversion treatment was performed on the hot stamp molded product obtained above, electrodeposition coating was performed, and a corrosion resistance test after painting was performed. The chemical conversion treatment was carried out with a chemical conversion treatment liquid PB-SX35T manufactured by Nihon Parkerizing Co., Ltd. Then, as the electrodeposition paint, Nippon Paint Co., Ltd.'s cationic electrodeposition paint Powernics 110 was used, and the hot stamp molded product was electrodeposited with a target of an electrodeposition film thickness of about 15 μm. After washing the hot stamped product with water, it was heated at 170 ° C. for 20 minutes and baked to prepare a test plate. The size of the test plate was 65 mm in length and 100 mm in width (the welded portion is in the center of the width).
Using this test plate, the automobile parts appearance corrosion test JASO M610-92 was used to evaluate the corrosion resistance after painting under the corrosion condition after 360 cycles (120 days).
[0180]
The evaluation of corrosion resistance after painting was performed with the maximum corrosion depth, and the weld metal part was evaluated by the following criteria using a point micrometer.
-Judgment criteria-
A: Maximum corrosion depth is less than 0.2 mm
D: Maximum corrosion depth is 0.2 mm or more
[0181]
The tensile strength column and the thickness column of the plated steel sheet after hot press forming of the plated steel sheets in Tables 2 to 4 indicate the nominal tensile strength and the nominal thickness of the base steel sheet. Further, the plated steel sheet indicates a steel sheet in which a base steel sheet is plated with aluminum.
[0182]
Further, in Table 4, the notations of "A", "B", and "C" in the exposed portion type column are as follows. In A, a first exposed portion where the base steel plate is exposed is formed.
"A": Removes aluminum plating layer and intermetallic compound layer
"B": Removes aluminum plating layer
"C": Aluminum plating layer and intermetallic compound layer remain (not removed)
[0183]
Further, in Table 4, the notations of "-" and "E" in the second plating portion type column are as follows.
"-": No second plating part (only the first exposed part is formed). "E": Aluminum plating layer and intermetallic compound layer remain
[0184]
In Table 4, the width of the second plated portion is the distance from the edge of the plated steel plate (steel plate for butt welding) to the boundary between the second plated portion and the first exposed portion measured by the method described above. is there.
[0185]
In Table 5, the numerical value in the plate thickness ratio column is the ratio of the plate thickness of the base steel sheet to the position corresponding to the first exposed portion and the position of the first plated portion of the plated steel sheet obtained by the above-mentioned equation (11). The value.
[0186]
[Table 5]
[0187]
In Table 5, the aluminum concentration of the first weld metal part is a value measured according to the method described above.
[0188]
As shown in Table 5, fatigue strength is excellent in No. 1 and No. 2 in which both the aluminum plating layer and the intermetallic compound layer are removed and the second plating portion is not provided. However, since the aluminum concentration in the first weld metal portion is small, the corrosion resistance after painting is inferior.
No. 3 in which the aluminum plating layer is removed to leave the intermetallic compound layer and does not have the first exposed portion of the base steel plate has excellent corrosion resistance after painting but inferior fatigue strength.
No. 4 in which neither the aluminum plating layer nor the intermetallic compound layer was removed has excellent post-painting corrosion resistance. However, the fatigue strength is inferior, and the static strength is also inferior.
On the other hand, as shown in Table 5, both the aluminum plating layer and the intermetallic compound layer are removed to form an exposed portion, and a second plating portion is formed at the edge of the plated steel sheet. Nos. 5 to 12 using the above are excellent in both fatigue strength and corrosion resistance after coating.
[0189]
(Second aspect)
Next, the second aspect of the present disclosure will be described with reference to FIGS. 15 to 20, 38 and 39, but the same parts as those in the above aspect are designated by the same reference numerals. The description is omitted, and only the differences will be described.
In the following description, when there is no distinction between the first exposed portion and the second exposed portion, it is simply referred to as an exposed portion.
The steel sheet according to the first aspect is provided with a second plating portion in a region including an edge, but the present invention is not limited to this. As long as the second plating portion is provided on the edge side and is at a position where it is taken into the weld metal portion during butt welding, the second plating portion and the edge may be separated from each other. Hereinafter, a second aspect in which the second exposed portion is provided between the second plating portion and the edge of the steel sheet will be described.
[0190]
In
the steel plate of the present disclosure, in addition to each configuration of the steel plate 100 of the first aspect, the base steel plate 12 is exposed between the edge 100A of the steel plate and the second plating portion 24 in the first direction. A second exposed portion is provided.
The distance from the edge of the steel sheet to the second plating portion 24 (width of the second exposed portion) is the distance from the edge of the first plating portion 26 to the second plating portion 24 (first exposure). It is preferably smaller than the width of the portion).
[0191]
FIG. 15 is a schematic cross-sectional view showing an example of an end portion of the steel plate of the present disclosure having an exposed portion of the base steel plate and a second plating portion in which the intermetallic compound layer and the aluminum plating layer remain. FIG. 16 is a schematic cross-sectional view showing another example of an end portion of the steel plate of the present disclosure having an exposed portion of the base steel plate and a second plating portion in which the intermetallic compound layer and the aluminum plating layer remain. Further, FIG. 17 is a schematic cross-sectional view showing another example of the end portion of the steel plate of the present disclosure having an exposed portion of the base steel plate and a second plating portion in which the intermetallic compound layer and the aluminum plating layer remain. is there.
[0192]
In FIGS. 15 to 17, 100C and 100D each represent an edge of the second plating portion 24. 100D represents the edge of the second plating portion 24 at the boundary with the second exposed portion 23 located closer to the edge 100A of the steel plate 100. 100C represents the edge of the second plating portion 24 at the boundary with the first exposed portion 22 located near the central portion (first plating portion 26) of the steel sheet 100.
[0193]
As shown in FIGS. 15 to 17, in addition to each configuration of the steel plate 100 of the first aspect, the steel plate 100 of the present disclosure includes the edge 100A of the steel plate 100 and the second plating portion 24 in the first direction F1. A second exposed portion 23 is provided between the two, from which the base steel plate 12 is exposed. In the first direction F1, the edge 100A of the steel sheet 100 and the second exposed portion 23 are adjacent to each other.
The second plating portion 24 is provided so as to be sandwiched between the first exposed portion 22 and the second exposed portion 23. The distance from the edge 100A of the steel plate 100 to the edge 100D of the second plating portion 24 (W2 shown in FIG. 15. The width of the second exposed portion 23 in the first direction F1. Hereinafter, simply referred to as the width of the second exposed portion 23. It is preferable that the distance from the edge 100B of the first plating portion 26 to the edge 100C of the second plating portion 24 (W1 shown in FIG. 15; the width of the first exposed portion 22) is smaller. That is, in the second plating portion 24, the relationship between the width of the first exposed portion 22 and the width of the second exposed portion 23 satisfies the relationship of W2 The
exposed portion is formed at the end of the planned welding portion of the steel plate 100. Then, as shown in FIG. 38, at the end portion where the exposed portions 22 and 23 are formed, which is the planned welding portion, the exposed portions 22 and 23 in which the base steel plate 12 is exposed on at least a part of both surfaces. Is provided. The exposed portions 22 and 23 have a first exposed portion 22 provided on at least one surface of the steel plate 100 in contact with the edge of the steel plate 100 and along the edge of the steel plate 100. In addition, it has a second exposed portion 23 that is in contact with the edge of the second plating portion 24 and is provided along the edge of the second plating portion 24. The width W2 of the second exposed portion 23 is shorter than the width W1 of the first exposed portion 22.
When the end portion where the exposed portion is formed is provided with a surface in which the second plating portion 24 is not provided and only the exposed portion is provided, the edge at the end of the steel sheet 100 to the edge at the first plating 26 An exposed portion (first exposed portion 22) is provided over the entire width up to 100B (see FIG. 16).
[0199]
The first exposed portions 22 formed on both sides of the end portions of the steel plate 100 may be formed as follows. That is, when the ends of the steel plate 100 are butt-welded, the steel plate 100 is formed in such a manner that the first exposed portion 22 in which the base steel plate 12 is exposed is formed between the weld metal portion and the first plating portion 26. The first exposed portion 22 is formed on the surface. The second plated portion 24 is provided in the vicinity of the edge of the steel plate 100 by forming a second exposed portion 23 with the edge 100A of the steel plate 100.
[0200]
The width of the range in which the exposed portions 22 and 23 are formed is often 0.1 mm or more, and preferably 5.0 mm or less. In the present disclosure, the width of the range in which the exposed portion is formed is the distance from the edge 100A at the end of the steel sheet 100 to the edge 100B at the first plating 26 (W1 and No. 1 in the case of FIG. 15). 2 Represents the sum of the width of the plated portion 24 and W2). Here, the position of the edge 100D of the first exposed portion 22 is preferably within 0.9 mm from the edge 100A of the steel sheet 100 in the direction opposite to F1. More preferably, the position of the edge 100D of the first exposed portion 22 is within 0.5 mm. The width of the second exposed portion 23 may be as close to 0 as possible, for example, 0.01 mm or more. The width of the second exposed portion 23 is preferably 0.8 mm or less from the viewpoint of improving fatigue strength. The preferred range of the width of the second exposed portion 23 is 0.05 mm to 0.40 mm.
When the butt welding is laser welding, the width of the range where the exposed portions 22 and 23 are formed is preferably 0.5 mm or more, and the width of the range where the exposed portions are formed is preferably 1.5 mm or less. By setting the width of the range in which the exposed portions 22 and 23 are formed to 0.5 mm or more, it is possible to prevent aluminum from remaining on the end portion of the weld metal portion when welding the tailored blank (with the end portion of the weld metal). The aluminum plating layer 14 does not come into contact). By setting the width of the range in which the exposed portions 22 and 23 are formed to 1.5 mm or less, deterioration of corrosion resistance after painting can be suppressed. When the butt welding is plasma welding, the width of the range in which the exposed portion is formed is preferably 1.0 mm or more, and the width of the range in which the exposed portion is formed is preferably 4.0 mm or less. By setting the width of the range in which the exposed portion is formed in the range of 0.2 mm to 4.6 mm (average), it becomes easy to suppress a decrease in the fatigue strength of the joint when it is made into a hot press molded product.
[0201]
The thickness of the base steel sheet 12 at the exposed portion at the end of the steel plate 100 is the average of the measured values at the first exposed portion 22. The thickness of the base steel sheet 12 at the first plating portion 26 is the average thickness in this region. The plate thickness ratio is an average value.
[0202]
The thickness of the base steel plate 12 at the first exposed portion 22 at the end of the steel plate 100 and the thickness of the base steel plate 12 at the center of the steel plate 100 are determined by cutting the steel plate 100 in the thickness direction and measuring the cut cross section with an optical microscope. It can be obtained by observing with. In the cut cross section, the thickness of the base steel plate 12 at the first exposed portion 22 and the thickness of the base steel plate 12 at the center of the steel plate 100 may be measured.
When there is a region where the second plating portion 24 is provided facing the exposed portion on the opposite surface of the surface where the second exposed portion is provided at the end portion of the steel sheet 100 applied as the blank material. The thickness of the base steel sheet 12 at the exposed portion is measured at the portion excluding this region. That is, the thickness of the base steel plate 12 in the exposed portion is an average value measured in the portion where the base steel plate 12 is exposed on both sides.
[0203]
Specifically, the thickness of the base steel plate 12 in the exposed portion is an average value obtained as follows. The thickness of the base steel plate 12 in the exposed portion is measured from the cross section of the steel plate 100 at a position where the width of the first exposed portion 22 in the first direction F1 is bisected. At this time, in a plan view, the longitudinal direction of the exposed portion is divided into five equal parts and measured at five points, and the average value is obtained.
Regarding the thickness of the second plating portion 24, as in the first aspect, the total length of the second plating portion 24 in the third direction (X direction) is divided into five equal parts in the longitudinal direction of the first exposed portion 22 at five locations. The thickness of the second plating portion 24 is obtained at the position where the width of the second plating portion 24 in the first direction F1 is divided into two equal parts, and the average value of the obtained values is defined as the thickness of the second plating portion 24.
The same applies to the thickness of the intermetallic compound layer 16.
[0204]
The second plating part 24 is provided on at least one side of the steel plate 100 by being sandwiched between the first exposed part 22 and the second exposed part 23 in the first direction F1. The second plating portion 24 is provided in a range in which the width W2 of the second exposed portion 23 is smaller than the width W1 of the first exposed portion 22.
[0205]
The second plating portion 24 formed on at least one surface of the end portion of the steel plate 100 is formed into a tailored blank after welding with the end faces of the steel plate 100 having the exposed portion and the second plating portion 24 abutting each other. It suffices that the second plating portion 24 is formed so as not to exist at the boundary between the weld metal and the steel plate 100 (exposed portion of the base steel plate 12). That is, the second plated portion 24 is provided with the second exposed portion 23 provided on at least one surface of the end portion of the steel plate 100 in the vicinity of the edge of the steel plate 100 so as to be contained in the weld metal after butt welding. It is provided between the first exposed portion 22 provided along the edge of the first plating portion 26.
[0206]
The width of the weld metal portion may be 0.4 mm to 6 mm. When the width of the weld metal portion is 0.4 mm, the width A1, which is the sum of the width of the second exposed portion 23 and the width of the second plating portion 24, may be 0.04 mm or more and less than 0.2 mm. Preferably, when the width of the first exposed portion 22 is B1, the total of A1 and B1 is preferably 0.5 mm or more. When the width of the weld metal portion is 1 mm, the width A1 is preferably 0.3 mm or less, and the total of the width A1 and the width B1 is preferably 0.8 mm or more. When the width of the weld metal portion is 2 mm, the width A1 is preferably 0.8 mm or less, and the total of the width A1 and the width B1 is preferably 1.3 mm or more. When the width of the weld metal portion is 6 mm, the width A1 is preferably 0.9 mm or less, and the total of the width A1 and the width B1 is preferably 3.3 mm or more.
The method for measuring the width of these parts is the same as the method for measuring the width of the exposed portion, which will be described later.
[0207]
Here, referring to FIG. 15, it is preferable that the width W2 of the second exposed portion 23 is 0.01 mm or more. The width W1 of the first exposed portion 22 is preferably 0.1 mm or more.
[0208]
When the second exposed portion is provided, the second plating portion 24 is preferably provided in the range from the edge 100A of the steel sheet 100 to 0.9 mm. It is more preferable that the second plating portion 24 is provided in the range from the edge 100A of the steel sheet 100 to 0.50 mm. When the second plating portion 24 is provided in this range, the second plating portion 24 is likely to be included in the weld metal after butt welding. Further, by setting the existing region of the second plating portion 24 to this range, at least the region from the edge 100A of the steel sheet 100 to the first plating portion side of more than 0.9 mm becomes the first exposed portion 22. As a result, at least the surface between the weld metal and the weld heat-affected zone after butt welding can be set as a region where a hard intermetallic compound is not generated. By defining the range of the existing region of the second plating portion 24 and the position of the first exposed portion 22 in this way, Al necessary for improving the corrosion resistance of the weld metal can be supplied to the weld metal, and the weld metal can be supplied. It is possible to prevent the formation of an intermetallic compound that reduces the fatigue strength at the boundary between the weld and the weld heat affected zone. The second plating portion 24 is more preferably provided in the range of the edge 100A to 0.4 mm of the steel sheet 100, and further preferably provided in the range of the edge 100A to 0.3 mm of the steel sheet 100.
[0209]
Further, the width of the second plating portion 24 provided at the end portion of the steel plate 100 is preferably the following width. When the butt welding is laser welding, the width of the second plating portion 24 is preferably 0.05 mm or more, and the width of the second plating portion 24 is preferably 0.40 mm or less. When used for plasma welding, the width of the second plating portion 24 is preferably 0.10 mm or more, and the width of the second plating portion 24 is preferably 0.60 mm or less.
When the width of the second plating portion 24 changes at each position in the longitudinal direction of the second plating portion 24, the width of the second plating portion 24 is changed to the second position of the second plating portion 24 in the longitudinal direction. 2 It may be specified as the maximum value of the width of the plated portion 24.
[0210]
Here, the width of the first exposed portion 22 is an average value obtained by measuring the width of the first exposed portion 22 at five points obtained by dividing the total length of the first exposed portion 22 in the longitudinal direction into five equal parts. Similarly, the width of the second exposed portion 23 is an average value obtained by measuring the width of the second exposed portion 23 at five points obtained by dividing the total length of the first exposed portion 22 in the longitudinal direction into five equal parts, and is the average value of the second plated portion 24. Is the average value of the width of the second plating portion 24 measured at five points obtained by dividing the total length of the first exposed portion 22 in the longitudinal direction into five equal parts.
The method of measuring the width of the first exposed portion 22, the width of the second exposed portion 23, and the width of the second plating portion 24 is as follows.
A measurement sample including a cross section (for example, a cross section along the first direction F1 in a plan view of the steel plate 100) in which the entire widths of the exposed portions 22, 23 and the second plating portion 24 formed at the end of the steel plate 100 can be observed. Is collected at 5 locations. The measurement sample is taken from five positions obtained by dividing the lengths of the exposed portions 22, 23 formed in the direction along the edge 100A of the steel plate 100 into five equal parts. Next, cutting is performed so that the cross section of the steel plate 100 is exposed. Then, the cut measurement sample is embedded in the resin, polished, and the cross section is enlarged with a microscope. Then, for each sample, the width of the second exposed portion 23, which is the distance from the edge 100A of the steel plate 100 to the second plating portion 24, and the distance from the second plating portion 24 to the first plating portion 26. 1 Measure the width of the exposed portion 22. In addition, the distance between both edges of the second plating portion 24 is measured for each sample.
[0211]
Further, as the ratio of the width of the second plating portion 24 formed at the end portion to be welded, the width of the second plating portion 24 and the width of the exposed portion (first exposed portion 22 and second exposed portion 23). The percentage of (width of the second plating portion 24 / width of the second plating portion 24 + width of the exposed portion), which is a value with respect to the total of (width of), is provided in the range of 3% to 50%. When the ratio of the width of the second plating portion 24 is within this range, the decrease in fatigue strength is suppressed, and excellent post-coating corrosion resistance can be effectively obtained. The ratio of the width of the second plating portion 24. On the other hand, the preferable upper limit of the width ratio of the second plating portion 24 is 40%, and the more preferable upper limit is 30%.
[0212]
In the steel plate 100 of the present disclosure, not only the aluminum plating layer 14 but also the intermetallic compound layer 16 is removed from at least a part of both sides at the end portion of the steel plate 100, and the exposed portion 22 where the base steel plate 12 is exposed. It has 23. Further, at the end portion where the exposed portions 22 and 23 are provided, the second plating portion 24 is provided between the two exposed portions 22 and 23. The second plating portion 24 is provided so that the width of the second exposed portion 23 is smaller than the width of the first exposed portion 22. That is, the steel plate 100 of the present disclosure does not have the hard and brittle intermetallic compound layer 16 in the exposed portions 22 and 23 where the base steel plate 12 is exposed. Further, in the steel sheet 100 of the present disclosure, the second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain is located near the edge of the steel sheet 100 and between the edge 100A of the steel sheet 100. It exists via the exposed portion 23.
[0213]
Therefore, the tailored blank obtained by using the steel plate 100 of the present disclosure as a blank material and butt-welding the end faces of the end portions of the steel plate 100 of the present disclosure having the exposed portion and the second plating portion 24 is a weld metal and the steel plate 100. It does not have a hard and brittle intermetallic compound layer 16 at the boundary with. The portion of the weld metal portion near the edge 100B of the first plating portion 26 does not contain the aluminum of the intermetallic compound layer 16 and the aluminum plating layer 14. Further, the second plating portion 24 is incorporated into the weld metal portion after butt welding (that is, the aluminum of the second plating portion 24 is mixed into the weld metal portion in an appropriate amount).
Therefore, even when this tailored blank is used as a hot press-formed product, it is considered that a decrease in fatigue strength of the joint is suppressed. In addition, by suppressing the generation of scale on the surface of the weld metal part, the chemical conversion processability is improved, and the adhesion of the paint is improved, so that welding is performed even after painting on a hot press molded product. It is considered that the metal part has excellent corrosion resistance after painting.
Further, since it is difficult for the intermetallic compound layer 16 and the aluminum of the aluminum plating layer 14 to be contained in the portion of the weld metal portion near the edge 100B of the first plating portion 26, the weld metal portion of this portion is softened and welded. It is possible to suppress a decrease in the fatigue strength of the metal portion.
[0214]
Further, in the steel plate 100 of the present disclosure, the second plating portion 24 exists in the vicinity of the edge 100A of the steel plate 100, separated from the edge 100A of the steel plate 100, and sandwiched between the two exposed portions 22 and 23. There is. Therefore, the second plating portion 24 is difficult to peel off in handling such as transportation before joining the steel plate 100. As a result, there is also an advantage that an appropriate amount of aluminum can be easily mixed into the weld metal portion.
[0215]
In the steel plate 100 of the present disclosure, a second plating portion 24 is formed at the end of a planned welding portion by being sandwiched between the first exposed portion 22 and the second exposed portion 23 of the base steel plate 12. The second plating portion 24 also includes the following aspects as long as the decrease in fatigue strength of the weld metal portion is suppressed and the corrosion resistance after painting can be maintained.
[0216]
For example, when a plated steel sheet is punched to obtain a punched member to be a blank material, a cutting means such as a shear may be adopted. When cut by a shear, in the region including the edge of the plated steel sheet, sagging may occur on one surface and burrs may occur on the other surface.
The intermetallic compound layer and the aluminum plating layer are removed by cutting, for example, the edges of the plated steel sheet in which sagging and burring have occurred. At this time, by grinding the surface where burrs are generated, the second exposed portion 23 can be provided in the region in contact with the edge of the plated steel sheet. Further, the second plating portion 24 can be provided so that the intermetallic compound layer 16 and the aluminum plating layer 14 remain closer to the central portion of the plated steel sheet than the region where burrs are generated. Further, the first exposed portion 22 can be provided closer to the central portion than the region to be the second plating portion 24. On the other hand, in the portion where the sagging occurs, the second plating portion 24 can be provided so that the intermetallic compound layer 16 and the aluminum plating layer 14 remain in the region including the edge of the plated steel sheet. The intermetallic compound layer 16 and the aluminum plating layer 14 may be removed so that the base steel plate 12 is exposed at the portion where the sagging occurs.
[0217]
FIG. 18 is a cross-sectional photograph showing an example of an end portion of the base steel plate 12 of the disclosed steel plate 100 having exposed portions 22, 23 and a second plating portion 24. The end portion of the steel plate 100 shown in FIG. 18 is an enlarged photograph of the end portion of the steel plate 100 when the surface where burrs are generated is removed by cutting to form the exposed portions 22, 23 and the second plating portion 24. Represents.
The second exposed portion 23 is provided by cutting the surface on which burrs are generated so as to expose the base steel plate 12. Further, the first exposed portion 22 is provided by cutting so as to expose the base steel plate 12. The second plating portion 24 is provided by cutting so that the first exposed portion 22 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain is formed. The second plating portion 24 shown in FIG. 18 has an intermetallic compound layer 16 and an aluminum plating layer 14.
[0218]
When the aluminum contained in the second plating portion 24 is mixed with the weld metal in an appropriate amount, the corrosion resistance of the weld metal portion after painting becomes excellent. Therefore, in the steel plate 100 of the present disclosure, when the surface where burrs are generated is cut, the aluminum plating layer 14 and the intermetallic compound layer 16 remaining closer to the center of the steel plate 100 than the portion where burrs are generated are second. It may be used as a plating portion 24. The second plating portion 24 may be cut to such an extent that the intermetallic compound layer 16 and the aluminum plating layer 14 remain.
[0219]
FIG. 19 is a schematic enlarged cross-sectional view showing another example of the end portion of the steel plate 100 of the present disclosure having the exposed portion and the second plated portion 24 of the base steel plate 12. FIG. 19 schematically shows a state in which the end portion of the steel sheet 100 in which sagging occurs on one surface of the end portion and burrs occur on the other surface is cut. On the surface where dripping occurs, the second plating portion 24 is provided along the edge of the steel sheet 100 by leaving the intermetallic compound layer 16 and the aluminum plating layer 14 in the portion where dripping occurs. Has been done. On the surface where burrs are generated, the first exposed portion 22 and the second plating portion 24 are provided by cutting. The second exposed portion 23 is formed by cutting the surface on which burrs are generated. Further, the second plating portion 24 is formed so that the intermetallic compound layer 16 and the aluminum plating layer 14 remain closer to the center portion of the steel sheet 100 than the second exposed portion 23. Further, the first exposed portion 22 is formed closer to the center portion of the steel sheet than the second plating portion 24.
[0220]
At the end of the steel sheet 100 shown in FIG. 19, the second plating portion 24 is provided at the portion where the sagging occurs, but the second plating portion 24 at the portion where the sagging occurs is cut. The base steel plate 12 may be exposed. Further, in the second plating portion 24 provided on both sides shown in FIG. 19, both layers of the intermetallic compound layer 16 and the aluminum plating layer 14 remain.
[0221]
As an example of a preferable method of forming the exposed portion and the second plated portion 24 on at least a part of both surfaces at the end portion of the plated steel plate (steel plate for butt welding), for example, the following method can be mentioned.
In the method, the intermetallic compound layer 16 and the aluminum plating layer 14 formed on the base steel sheet 12 are removed by cutting at least a part of both sides at the end portion of the plated steel sheet to expose the base steel sheet 12. This is a method (referred to as forming method C) of providing the exposed portion, the second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain.
In the step, at the end portion provided with the exposed portion, the second exposed portion 23 and the first plated portion 26 are in contact with the edge of the plated steel sheet as exposed portions on both sides of the plated steel sheet and along the edge of the plated steel sheet. The first exposed portion 22 is formed in contact with the edge of the first plating portion 26 along the edge of the first plating portion 26. When performing the above steps, it is preferable that the distance from the edge of the plated steel sheet to the second plated portion 24 is smaller than the distance from the edge of the first plated portion 26 to the second plated portion 24.
[0222]
The forming method C is, for example, a method of forming an exposed portion and a second plating portion 24 at an end portion of a plated steel sheet as follows. First, as a plated steel sheet (blank material) before forming a steel sheet, a plated steel sheet cut to a desired size is prepared. Next, the aluminum plating layer 14 and the intermetallic compound layer 16 formed on both sides of the base steel sheet 12 are removed by cutting at least a part of both sides of the edge of the plated steel sheet after cutting. Then, a second exposed portion 23 in which the base steel plate 12 is exposed is formed at the end portion of the plated steel plate along the edge of the plated steel plate. At this time, the second plated portion 24 is formed adjacent to the second exposed portion 23 provided along the edge of the edge of the plated steel sheet. Further, adjacent to the second plating portion 24, the first exposed portion 22 is formed along the edge of the first plating portion 26. The second plating portion 24 is formed so that the width of the second exposed portion 23 is smaller than the width of the first exposed portion 22.
[0223]
If the above-mentioned exposed portions 22, 23 and the second plating portion 24 are formed on at least a part of both surfaces at the end portion of the steel sheet 100, the exposed portions 22, 23 and the second plating portion 24 are formed on the end portions. The order is not limited to the above-mentioned forming method C.
As an example of another preferable method of forming the above-mentioned exposed portions 22, 23 and the second plated portion 24 on at least a part of both surfaces at the end portion of the plated steel sheet, for example, the following method can be mentioned.
[0224]
In the method, the aluminum plating layer 14 and the intermetallic compound layer 16 formed on the base steel sheet 12 are removed by cutting on at least a part of both sides of the plated steel sheet, and the base steel sheet 12 is exposed. This is a method (referred to as forming method D) of providing a portion, a second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain, and a first plating portion 26.
In the process, the first process and the second process are performed.
As shown in FIG. 39 (A), in the first process, the first exposed portion is formed on at least one surface of the plated steel plate 101 at the portion serving as the end portion where the first plated portion 26 and the exposed portions 22 and 23 are provided. Adjacent to the first exposed portion region 22A and the first exposed portion region 22A to be 22, and adjacent to the second plating portion region 24A and the second plating portion region 24A to be the second plating portion 24, and the second exposed portion 23. The second exposed portion 23A and the second exposed portion 23A, which are adjacent to the second plated portion region 24B and the second plated portion region 24B which are the second plating portions 24, and which are the first exposed portions 22. 1 The exposed portion region 22B is formed in this order.
[0225]
In the second process, as shown in FIG. 39 (B), the plated steel sheet 100 is cut in the second exposed portion region 23A, so that the first exposed portion 22 and the plated steel plate along the edge of the first plated portion 26 A second exposed portion 23 along the edge of 101 and a second plated portion 24 sandwiched between the exposed portions 22 and 23 are formed. By the above steps, two steel plates 100 are manufactured.
In the second process, it is preferable that the distance from the edge of the plated steel sheet 101 to the second plated portion 24 is smaller than the distance from the edge of the first plated portion 26 to the second plated portion 24.
[0226]
Specifically, the forming method D is, for example, the following method. First, a plated steel sheet 101 (blank material) that has been punched and cut to a desired size is prepared. Next, the aluminum plating layer 14 and the intermetallic compound layer 16 formed on the base steel plate 12 were removed from the cut plated steel plate 101 by cutting, and the exposed portion region where the base steel plate 12 was exposed. To form. Three exposed portion regions are formed in regions other than the first plating portion 26, for example, so as to extend in one direction via the second plating portion 24. These three exposed portion regions include an exposed portion region serving as a first exposed portion 22 and an exposed portion region serving as a second exposed portion 23. In the region sandwiched between the three exposed portions, the region of the second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain becomes the first exposed portion 22 and the first exposed portion. Two are formed so as to be adjacent to each other with the exposed portion region to be the portion 22. Then, it is cut at the exposed portion region (that is, the exposed portion region located at the center of the three exposed portion regions) to be the second exposed portion 23, and becomes two plated steel plates (blank materials). The exposed portion region to be the second exposed portion 23 is cut as a plated steel plate after cutting so that the second exposed portion 23 is cut along the edge of the plated steel plate. Then, the obtained plated steel sheet becomes a steel sheet before forming the tailored blank.
[0227]
In the case of the forming method D, the width of the exposed portion region to be the second exposed portion 23 is often 0.05 mm to 12 mm, preferably 0.2 mm to 10 mm. Further, the position for cutting the exposed portion region to be the second exposed portion 23 may be cut at a position near the center line of the exposed portion region so as to have a target width, and at a position other than the vicinity of the center line. You may cut it. Further, the width of the exposed portion region where the base steel plate 12 is exposed may be removed by cutting so as to have a desired width.
[0228]
The total width of the first exposed portion 22, the second exposed portion 23, and the second plating portion 24 formed by the above forming method C and the forming method D is less than half the width of the molten region (welded metal portion). It should be 1.1 times or more larger. This makes it possible to prevent the molten region from coming into contact with the first plating portion 26.
Further, the width of the second plating portion 24 in the steel plate 100 before the tailored blank is formed is formed so as to be a width included in the molten region after the steel plate 100 is butt-welded.
Within these ranges, an appropriate amount of aluminum is mixed in the weld metal portion after the steel sheet 100 is butt-welded, so that the corrosion resistance after painting is excellent and the (static) tensile strength is also lowered. It is suppressed. Further, since the hard and brittle intermetallic compound layer 16 is not provided at the boundary between the weld metal portion and the steel sheet 100, a decrease in fatigue strength of the steel sheet 100 after hot press forming is suppressed.
[0229]
FIG. 20 is a schematic cross-sectional view showing an example of the tailored blank of the present disclosure.
The tailored blank 300 of the present disclosure includes a first weld metal portion and at least two steel plate portions connected via the first weld metal portion. Each of at least two steel plate portions indicates a portion corresponding to the steel plate as a result of butt welding the steel plate (steel plate for butt welding) of the present disclosure. Specifically, each of the at least two steel plate portions includes a first plating portion 26 in which an intermetallic compound layer 16 and an aluminum plating layer 14 are provided in order from the base steel plate 12 side on the surface of the base steel plate 12. A first exposed portion 22 from which the base steel plate 12 is exposed is provided. In the tailored blank of the present disclosure, in the second direction F3, the first plating portion 26, the first exposed portion 22, and the first weld metal portion are the first plating portion 26, the first exposed portion 22, and the first weld metal portion. They are arranged on the same surface in order.
[0230]
The tailored blank 300 shown in FIG. 20 is formed by butt-welding the ends of the planned welding portions of the steel plate 110 of the present disclosure and the steel plate 120 of the present disclosure. In the tailored blank 300, the steel plate 110 and the steel plate 120 having a thickness smaller than that of the steel plate 110 are joined by the first weld metal portion 150. Further, the tailored blank 300 has a first exposed portion 22 adjacent to the first weld metal portion 150, and the steel plate 110 is adjacent to the side of the first exposed portion 22 away from the first weld metal portion 150. , 120 first plating portions 26. The second plating portion 24 provided at the end portion of the steel plate 110 and the planned welding portion of the steel plate 120 is incorporated into the first weld metal portion 150 by butt welding and disappears from the end portions of the steel plates 110 and 120. ing.
It is preferable that all the second plated portions 24 at the abutted ends of the steel plates 110 and 120 are incorporated (included) in the first weld metal portion 150.
[0231]
The second aspect is different from the first aspect in manufacturing the hot press molded product as follows.
The following steps are performed after the plated steel sheet in which both sides of the base steel sheet 12 are plated with aluminum is punched to obtain a punched member.
[0232]
The aluminum plating layer 14 and the intermetallic compound layer 16 are removed from at least a part of both sides of the end portion of the plated steel sheet to form an exposed portion of the base steel sheet 12. At this time, on at least one side of the edge of the plated steel sheet, a second exposed portion 23 provided along the edge of the edge of the plated steel sheet and a first exposed portion 23 provided along the edge of the first plated portion 26. The exposed portion 22 and the second plated portion 24 sandwiched between these two exposed portions 22 and 23 and provided near the edge of the plated steel sheet are formed to obtain the steel plate 100 of the present disclosure.
Here, the exposed portions 22, 23 and the second plated portion 24 formed at the ends of the plated steel sheet are formed in a state where the plated steel sheet is wound into a coil and then the plated steel sheet wound into the coil is pulled out. You may. In this case, after the exposed portion is formed, a punching process is performed so that the exposed portion and the second plating portion 24 are held at the end portion of the plated steel sheet to obtain a punched member.
[0233]
Further, the exposed portion and the second plating portion 24 formed at the end of the plated steel sheet are formed after the plated steel sheet wound in a coil shape is pulled out and the pulled out plated steel sheet is punched to form a punched member. You may. In this case, an exposed portion and a second plating portion 24 may be formed at the end of the punched member. Further, in the portion other than the end portion of the punched member, the exposed region A serving as the first exposed portion 22 and the first residual portion serving as the second plating portion 24 in the width direction of the plated steel sheet so as to extend in one direction, for example. The region, the exposed region B serving as the second exposed portion 23, the second remaining region serving as the second plating portion 24, and the exposed region C serving as the first exposed portion 22 are formed in this order. After that, the steel plate 100 of the present disclosure may be obtained by cutting in the exposed region B serving as the second exposed portion 23.
[0234]
It should be noted that also for the steel sheet 100 of the second aspect, the steel sheet required to bring the aluminum concentration contained in the first weld metal portion of the tailored blank described in the first aspect to 0.065% by mass to 1% by mass. The concept of specifications can be applied.
[0235]
Hereinafter, examples of the second aspect of the present disclosure will be illustrated, but the present disclosure is not limited to the following examples.
[0236]
First, using the base steel sheet having the chemical composition shown in Table 2 described above, a plated steel sheet plated with aluminum was prepared so as to have the thickness shown in Table 6.
[0237]
[Table 6]
[0238]
Then, this plated steel sheet was cut out to obtain a square plated steel sheet (blank material) having a side of 10 cm. Next, an exposed portion and a second plated portion were formed on at least a part of both sides at the end portion of the planned welding portion of the prepared plated steel sheet.
In some plated steel sheets, the aluminum plating layer and the intermetallic compound layer were removed, and only the exposed portion was formed, and the second plating portion was not formed.
[0239]
The exposed portion was exposed by removing the aluminum plating layer and the intermetallic compound layer formed on both sides according to the exposed portion type shown in Table 7, respectively, to expose the base steel plate.
[0240]
[Table 7]
[0241]
The exposed portion was formed by cutting with an end mill. Further, the exposed portion was formed on both sides of the end portion of the plated steel sheet over a total length of 10 cm, excluding only one side of the four sides of the plated steel sheet and the region including the edge of the plated steel sheet. The width of the exposed portion is the sum of the distance from the edge of the plated steel sheet to the second plating portion and the distance from the edge of the first plating portion to the second plating portion. No. 1 shown in Table 7 does not have a second plating portion. That is, the numerical value in the "distance (mm) from the edge of the first plating portion to the second plating portion" in No. 1 is from the edge of the region other than the first plating portion to the edge of the edge of the plated steel sheet. It represents the distance.
At the same time as forming the exposed portion, the second plated portion was formed in a region sandwiched between the two exposed portions, separated from the edge of the plated steel sheet, according to the second plated portion type shown in Table 7. The second plating portion was formed so as to have the width of the second plating portion shown in Table 7.
[0242]
Next, as shown in Table 7, two of the above-mentioned plated steel plates (plated steel plates for butt welding) are prepared (plated steel plate 1 and plated steel plate 2), the end faces of the planned welding portions are butted, and laser welding is performed. Butt welding was performed to prepare a tailored blank. Welding was adjusted so as to perform penetration welding under the conditions of a laser output of 3.0 kW to 5.0 kW and a welding speed of 4.0 m / min to 7.0 m / min.
The prepared tailored blank was held in a furnace heated to 920 ° C. for 4 minutes, then molded with a water-cooled mold and quenched to prepare a flat plate hot stamped product.
Here, the Vickers hardness of the weld metal joining the plated steel sheet 1 and the plated steel sheet 2 was HV450 or higher.
[0243]
(Fatigue strength test and joint static strength)
The test was carried out in the same manner as in Example 1 of the first aspect. The test results are shown in Table 8.
[0244]
[Table 8]
[0245]
(Corrosion resistance test after painting)
The test was carried out in the same manner as in Example 1 of the first aspect. The determination criteria are the same as in Example 1.
The plated steel sheets in Tables 6 and 7 show steel sheets obtained by plating the base steel sheet with aluminum.
In Table 7, the notation of "A", "B", and "C" in the exposed portion type column and the notation of "-" and "E" in the second plating portion type column are the same as those in the first embodiment. ..
[0246]
In Table 7, "distance from the edge of the plated steel sheet to the second plating portion", "width of the second plating portion", and "distance from the edge of the first plating portion to the second plating portion" are described above. It was measured by the method. On the surface where the second plating portion is not formed, the numerical value described in the "distance from the edge of the first plating portion to the second plating portion" is the distance from the edge of the first plating portion to the edge of the plated steel sheet. Represent.
[0247]
In Table 8, the numerical value in the plate thickness ratio column is the ratio of the plate thickness of the base steel sheet obtained from the equation (29) at the position corresponding to the first exposed portion of the plated steel sheet and the position corresponding to the first plated portion. The value. Each thickness is measured by the method described above.
Plate thickness ratio = (Thickness of base steel plate at first exposed part: tb) / (Thickness of base steel plate other than the end of plated steel plate: ta) ... (29)
[0248]
In Table 8, the aluminum concentration of the first weld metal part is a value measured according to the method described above.
[0249]
As shown in Table 8, No. 1 having both the aluminum plating layer and the intermetallic compound layer removed and having no second plating portion has a low aluminum concentration in the first weld metal portion, so that the corrosion resistance after painting is high. It is inferior.
On the other hand, as shown in Table 8, both layers of the aluminum plating layer and the intermetallic compound layer are removed to form an exposed portion, and further, the exposed portion is sandwiched between the two exposed portions in the vicinity of the edge of the plated steel sheet. Nos. 2 to 9 using the steel plate on which the two-plated portion is formed are excellent in both fatigue strength and corrosion resistance after painting.
[0250]
(Third aspect)
Next, the third aspect of the present disclosure will be described with reference to FIGS. 21 to 33, but the same parts as those in the above aspect will be designated by the same reference numerals and the description thereof will be omitted. Only the points will be described.
[0251]
As
shown in FIG. 21, in the tailored blank 300 manufactured by the tailored blank manufacturing method of the present disclosure, two steel plates 100 and 200 are first welded between the steel plates 100 and 200. It is configured by butt welding with a metal portion 150 sandwiched between them.
In the following, first, the configuration of the steel sheet 100 before butt welding shown in FIG. 22 will be described.
[0252]
The aspect of the steel sheet 100 of the present disclosure is the same as that of the steel sheet 100 in the first aspect.
The aluminum plating layer 14 is provided on the first surface of the base steel plate 12 and the second surface on the side opposite to the first surface, respectively. The intermetallic compound layer 16 is formed between the first surface of the base steel plate 12 and the aluminum plating layer 14 provided on the first surface. Further, the intermetallic compound layer 16 is formed between a second surface opposite to the first surface of the base steel plate 12 and an aluminum plating layer 14 provided on the second surface.
[0253]
The thickness of the base steel sheet 12 in the aluminum plating layer 14 per one side (one layer) is a (μm) (micrometer). The thickness of the base steel sheet 12 in the intermetallic compound layer 16 per one side (one layer) is b (μm).
[0254]
In the steel plate 100 configured as described above, referring to FIG. 22, first exposed portions 22 in which the base steel plate 12 is exposed are formed on both sides of the end portions located around the steel plate 100. A first plating portion 26 in which an intermetallic compound layer 16 and an aluminum plating layer 14 are provided on a base steel plate 12 is provided on the central portion side of the steel plate 100 with respect to the first exposed portion 22. The second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain on at least one side of the end portion located around the steel plate 100 and on the edge 100A side of the steel plate 100 with respect to the first exposed portion 22. Is formed.
In this example, the aluminum plating layer 14 and the intermetallic compound layer 16 remain in the second plating portion 24. In this example, the second plating portion 24 is formed on one side of the end portion of the steel plate 100, but the second plating portion 24 may be formed on both sides of the end portion of the steel plate 100, respectively.
[0255]
With reference to FIG. 22, the steel plate 200 includes the base steel plate 12 of the steel plate 100, the aluminum plating layer 14, the base steel plate 112 configured in the same manner as the intermetallic compound layer 16, the aluminum plating layer 114, and the intermetallic compound layer 116. ,have.
In this example, the base steel plate 112 differs from the base steel plate 12 only in thickness. The base steel plate 112 and the base steel plate 12 may have the same thickness.
First exposed portions 122 on which the base steel plate 112 is exposed are formed on both sides of the end portions located around the steel plate 200. A second plating portion 124 in which the aluminum plating layer 114 and the intermetallic compound layer 116 remain is formed on one side of the end portion located around the steel plate 200 on the edge side of the steel plate 200 with respect to the first exposed portion 122. ing. A first plating portion 126 in which an intermetallic compound layer 116 and an aluminum plating layer 114 are provided on a base steel plate 112 is provided on the central portion side of the steel plate 200 with respect to the first exposed portion 122.
[0256]
The first weld metal part is formed by melting and solidifying the ends of the two steel plates when the two steel plates are butt-welded. The concentration of aluminum contained in the first weld metal portion is preferably 0.065% by mass to 1% by mass.
[0257]
Next, the first exposed portions 22, 122 and the second plated portions 24, 124 are formed on the plated steel plate to manufacture the steel plates 100 and 200, and the steel plates 100 and 200 are butt welded to each other. The method for manufacturing the tailored blank of the present disclosure for manufacturing the tailored blank 300 will be described. FIG. 23 is a flowchart showing the tailored blank manufacturing method S10 of the present disclosure.
In this disclosure, the tailored blank manufacturing method S10 using the two steel plates of the present disclosure will be described, but the number of welding steel plates used in the tailored blank manufacturing method may be three or more. Then, of the two or more welding steel sheets, at least one steel sheet manufactured by the steel plate manufacturing method of the present disclosure may be used.
[0258]
First, in the steel sheet manufacturing process (manufacturing method of steel sheet for butt welding) (step S11 shown in FIG. 23), the plated steel sheet manufacturing step S12 is performed. In the plated steel sheet manufacturing process S12, the plated steel sheet 101 shown in FIG. 24 is manufactured. In the plated steel sheet manufacturing step S12, a plated steel sheet 101 in which the intermetallic compound layer 16 and the aluminum plated layer 14 are provided in this order from the base steel sheet 12 side on each surface of the base steel sheet 12 is manufactured by a known method. In the plated steel sheet 101, the first exposed portion 22 and the second plated portion 24 are not formed on the above-mentioned steel plate 100.
Here, the thickness of the plated steel sheet 101 is tμm. The thickness of the plated steel sheet 101 is equal to the thickness of the first plated portion 26 of the steel sheet 100 shown in FIG.
When the plated steel sheet manufacturing step S12 is completed, the process proceeds to the removing step S14 in step S14. The removal step S14 is a step of mechanically removing the aluminum plating layer 14 and the intermetallic compound layer 16.
[0259]
Next, in the removal step S14, the low portion forming step S15 is performed.
In the low portion forming step S15, as shown in FIG. 25, the plated steel plate 101 is cut and a part of the plated steel plate 101 is deformed to form the low portion region R2 on the surface of the base steel plate 12 of the plated steel plate 101. .. The lower region R2 is formed at the edge of the base steel plate 12.
Here, the first direction F1 is defined. The first direction F1 is perpendicular to the thickness direction of the plated steel sheet 101, and is a direction from the central portion of the plated steel sheet 101 in a plan view toward one edge of the plated steel sheet 101. The first direction F1 corresponds to the first direction F1 of the steel sheet 100 when the plated steel sheet 101 is processed into the steel sheet 100. The low portion region R2 referred to here is in the thickness direction as compared with the virtual surface T1 in which the surface of the base steel plate 12 that is not deformed at the time of cutting (for example, the first exposed portion 22) is extended in the first direction F1. It means a region of the aluminum plating layer 14 and the intermetallic compound layer 16 located on the inner side of the base steel plate 12. When the virtual surface T1 is viewed in a cross section perpendicular to the thickness direction, it becomes a virtual line.
[0260]
In this example, in the low portion forming step S15, the plated steel sheet 101 is cut by a mechanical method of shirring (shearing) to form a low portion region R2 on the plated steel sheet 101. Instead of the shirring process, a blanking process (punching process) may be used to form the low portion region R2 on the plated steel sheet 101. The mechanical method referred to here means a method in which a tool is brought into direct contact with the plated steel sheet 101 and the plated steel sheet 101 is processed by the contacted tool.
Specifically, in the low portion forming step S15, as shown in FIG. 24, the plated steel plate 101 is placed on the upper surface 401a of the support base 401 of the shirring device 400. The upper surface 401a is flat and is arranged along a horizontal plane. At this time, the end portion of the plated steel sheet 101 is arranged so as to protrude from the support base 401.
[0261]
The blade portions 402 of the shirring device 400 are arranged above the upper surface 401a of the support base 401 at regular intervals S from the support base 401 along the upper surface 401a.
When the blade portion 402 is moved downward and the plated steel sheet 101 is cut in the thickness direction of the plated steel sheet 101 as shown in FIG. 25, the end portion of the plated steel sheet 101 is cut. At this time, a sagging low portion region R2 is formed on the first surface 101A of the plated steel sheet 101. A protruding portion 38, which is a burrs, is formed on the lower surface of the plated steel sheet 101.
Here, the deepest low part depth of the low part region R2 is x (μm). The low portion depth x indicates (the maximum value) of the distance from the virtual surface T1 to the surface of the base steel plate 12 in the low portion region R2. The low depth x can be measured with a known laser profile meter or the like.
[0262]
FIG. 26 shows a cross-sectional photograph showing an example of a state in which the low portion region R2 is formed on the plated steel sheet 101 of the present disclosure.
The lower region R2 is formed in a range of 0.79 mm along the first surface 101A from the edge of the plated steel sheet 101. The low depth x is 178 μm.
By adjusting the material of the plated steel sheet 101, the interval S, and the like, the protruding portion 38 is formed, and at the same time, the lower surface of the plated steel sheet 101 is deformed as shown by the alternate long and short dash line in FIG. R3 may be formed. The alternate long and short dash line represents the shape of the lower surface of the plated steel sheet 101.
In this case, in the low portion forming step S15, the low portion region R2 is formed on the upper surface of the plated steel sheet 101, and the low portion region R3 is formed on the lower surface. For example, it is considered that the low portion region R3 is formed by pulling the material forming the plated steel sheet 101 toward the protruding portion 38 side by the rigidity of the plated steel sheet 101 when the protruding portion 38 is formed.
When the low portion forming step S15 is completed, the process proceeds to step S17.
[0263]
Next, in the cutting step (deletion step) S17, the plated steel sheet 101 is cut by using a cutting process which is a mechanical method to form the first exposed portion 22 and the second plated portion 24 to manufacture the steel sheet 100. To do. In the present disclosure, an end mill is used for cutting, and at least the aluminum plating layer 14 and the intermetallic compound layer 16 existing outside the plated steel sheet 101 in the thickness direction from the virtual surface T1 are cut and removed by the end mill. The blade of the end mill rotating around the axis is brought into direct contact with the plated steel sheet 101 to cut the plated steel sheet 101.
In the cutting process S17, for example, a cutting tool, an end mill, a metal saw, or the like is used in addition to the end mill. In the removing step, the aluminum plating layer 14 and the intermetallic compound layer 16 may be ground and removed. A grindstone, grinder, or the like is used for grinding.
[0264]
In the cutting step S17, the region R5 from the edge of the plated steel sheet 101 to the transcendental position P exceeding the low region R2 is cut in the direction opposite to the first direction F1. The transcendental position P is a position that becomes the edge 100B of the first plating portion 26 in a later step, and the range between the low portion region R2 and the transcendental position P becomes the first exposed portion 22. At this time, the depth of cutting the region R5 of the plated steel sheet 101 is constant. As a result, the manufacturing cost required for cutting can be suppressed. The aluminum plating layer 14 and the intermetallic compound layer 16 on the lower region R2 in the region R5 need not be cut.
The cutting depth of the plated steel sheet 101 is less than the total value of the thickness a of the aluminum plating layer 14, the thickness b of the intermetallic compound layer 16, and the low depth x. That is, cutting is performed so that at least a part of the intermetallic compound layer 16 and the aluminum plating layer 14 located in the lower region R2 remains.
As shown in FIG. 22, in the cutting step S14, the depth (length) in the thickness direction of the plated steel sheet 101 for cutting the aluminum plated layer 14 and the intermetallic compound layer 16 per side of the plated steel sheet 101 is yμm.
[0265]
By the above cutting, as shown in FIG. 22, the base steel plate 12 is exposed to the outside between the low portion region R2 and the transcendental position P in the first direction F1, and the first exposed portion 22 is formed. A second plating portion 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 remain is formed on the lower region R2 on the edge side of the plated steel sheet 101 with respect to the first exposed portion 22. In the first direction F1, on at least one surface of the base steel plate 12, the edges of the first plating portion 26, the first exposed portion 22, the second plating portion 24, and the plated steel plate 101 are formed on the first plating portion 26. The first exposed portion 22, the second plated portion 24, and the edge of the plated steel plate 101 are arranged in this order. In the first direction F1, at least the edges of the first plating portion 26, the first exposed portion 22, and the plated steel plate 101 are on the other surface of the base steel plate 12, the first plating portion 26, the first exposed portion 22, and the like. They are arranged in the order of the edge of the plated steel sheet 101.
[0266]
The steel sheet 100 is manufactured by forming the first exposed portion 22 and the second plated portion 24 on the plated steel sheet 101 by the above cutting.
Even if the first plated portion 26, the first exposed portion 22, the second plated portion 24, and the edge of the plated steel plate are arranged in this order on the other surface of the base steel plate 12 in the first direction. Good.
In the steel plate 100, the thickness of the base steel plate 12 corresponding to the portion where the first exposed portion 22 and the second plating portion 24 are formed is set to the portion where the first exposed portion 22 and the second plating portion 24 are not formed. It may be thinner than the thickness of the corresponding base steel plate 12.
[0267]
FIG. 27 shows a cross-sectional photograph showing an example of a state in which the first exposed portion 22 and the second plating portion 24 are formed on the steel plate 100 of the present disclosure.
[0268]
In this example, as shown in FIG. 22, the first exposed portion 22 is also formed on the second surface 101C on the side opposite to the first surface 101A of the steel sheet 100.
Here, the distance (width of the second plating portion 24) from the edge 100A of the steel sheet 100 to the edge 100C is set to Mμm. The distance between the first plating portion 26 and the second plating portion 24 (width of the first exposed portion 22) is N μm.
For example, when the depth x of the low portion exceeds the thickness a of the aluminum plating layer 14, the aluminum plating layer 14 remains in the second plating portion 24.
[0269]
That is, when the aluminum plating layer 14 is to be removed in the region where the low portion region R2 is not formed, the first surface 101A of the plated steel sheet 101 is mechanically formed in a plane by the thickness of the aluminum plating layer 14. Removed by. When the cutting depth y exceeds the thickness a of the aluminum plating layer 14, the aluminum plating layer 14 can be removed in the region where the low portion region R2 is not formed by the above mechanical method. However, in the region where the low region R2 is formed, the position of the aluminum plating layer 14 is in the thickness direction by the depth of the low region R2 as compared with the region where the low region R2 is not formed. It will be in a state of running away. Therefore, the aluminum plating layer 14 remains on the lower region R2 as described above.
[0270]
At this time, it is preferable to satisfy the equations (31) to (36).
9 ≦ a + b <60 ・ ・ (31)
2% ≦ (x / t) ≦ 15% ・ ・ (32)
a + b In the method for manufacturing a hot press molded product of the present disclosure, the tailored blank 300 manufactured in the tailored blank manufacturing method S10 is hot press molded to obtain a hot press molded product (hot). (Stamp molded product) is manufactured.
[0289]
In the steel pipe manufacturing method of the present disclosure, the ends of the open pipe made of the steel plate 100 manufactured in the steel plate manufacturing method S11 are welded to each other to manufacture the steel pipe.
In the method for manufacturing a steel pipe of the present disclosure, the steel plate 100 may be obtained by purchasing or the like without manufacturing the steel plate 100, and the steel pipe may be manufactured using the obtained steel plate 100.
In this case, in the method for manufacturing a steel pipe, the steel sheet 100 is formed in an open tubular shape so that two end portions in the circumferential direction face each other and a second plating portion 24 is arranged at at least one of the two end portions. To do. Then, the two ends of the steel sheet 100 are butt-welded and the two ends are connected via the third weld metal portion.
At this time, it is preferable to incorporate all of the second plating portion 24 melted during butt welding into the third weld metal portion.
[0290]
In the manufacturing method of the hollow hardened molded product of the present disclosure, the steel pipe manufactured by the steel pipe manufacturing method is hardened to manufacture a hollow hardened molded product (hollow hot stamp molded product). To do.
[0291]
Hereinafter, examples of the third aspect of the present disclosure will be illustrated, but the present disclosure is not limited to the following examples.
[0292]
First, the plated steel sheet was cut under the conditions shown in Table 9 from the steel sheet 1 to the steel sheet 7 using the base steel sheet having the chemical composition shown in Table 2 described above.
[0293]
[Table 9]
[0294]
In Table 9, the tensile strength (MPa) of the steel sheet 1 to the steel sheet 7 after hot press forming, the thickness t (μm) of the plated steel sheet, the total thickness of both layers (a + b) (μm), and the plated steel sheet were cut. Specific contents, low part depth x (μm), value of the ratio of bottom depth to plate thickness (x / t) according to equation (32), width of low part region (μm), deepest part of low part region The distance N (μm) from the edge of the plated steel sheet is shown.
In the steel plates 1 to 7, the length of the aluminum plating layer and the intermetallic compound layer cut from the edge of the plated steel plate (value of (M + N) in FIG. 22) is set to 1500 μm, respectively.
[0295]
The tensile strength of the steel plate 1, the steel plate 4, and the steel plate 7 after hot press forming is 1300 MPa. For example, the Al amounts of the steel plates 1 to 4 and the steel plate 7 are 0.02% from Table 2. The tensile strength of the steel plate 5 is 1500 MPa, and the tensile strength of the steel plate 6 is 1800 MPa.
The thickness t of the steel plate 1, the steel plate 4, and the steel plate 7 is 1200 μm, respectively. The thickness t of the steel plate 5 is 1600 μm, and the thickness t of the steel plate 6 is 1800 μm.
The total thickness of both layers means the total thickness of the aluminum plating layer and the thickness of the intermetallic compound layer. The total thickness of both layers of the steel plate 1 to the steel plate 7 is 30 μm.
The specific content obtained by cutting the plated steel sheet represents the specific content obtained by processing the steel sheet 1 to the steel sheet 7.
Although the plated steel sheet 1 was cut by laser processing, the low portion region was not formed by the partial pressing method or the like. Further, the steel plate 1 is not formed with the first exposed portion 22 by laser machining. For the steel plates 2 to 6, the plated steel plates were cut by shirring. In the steel plate 7, the plated steel plate was cut by laser processing, and then a low portion region was formed by a partial pressing method.
[0296]
In the steel sheet 1, since the low portion region is not formed, the low portion depth x is 0 μm.
The lower depths x of the steel plate 2 to the steel plate 7 are 30 μm, 60 μm, 150 μm, 80 μm, 90 μm, and 60 μm, respectively.
As a result, the values of the ratio (x / t) of the bottom depth to the plate thickness according to the equation (32) of the steel plates 2 to 7 are 0.0%, 2.5%, 5.0% and 12.5%, respectively. , 5.0%, 5.0%, 5.0%.
Since the low portion region is not formed in the steel sheet 1, the width of the low portion region is 0 μm.
The widths of the lower regions of the steel plate 2 to the steel plate 7 are 300 μm, 500 μm, 700 μm, 500 μm, 500 μm, and 1000 μm, respectively.
[0297]
Since the low portion region is not formed in the steel plate 1, there is no value of the distance between the deepest portion of the low portion region and the edge of the plated steel sheet.
In the steel plates 2 to 6, since the low portion region is formed by the shirring process, the deepest portion of the low portion region is located at the edge of the plated steel sheet. Therefore, the distance between the deepest portion of the low portion region and the edge of the plated steel sheet is 0 μm, respectively.
In the steel plate 7, the same distance is 500 μm.
[0298]
The distance N means the distance between the edge 100B of the first plating portion 26 and the second plating portion 24 when the aluminum plating layer and the intermetallic compound layer are cut as described above. At this point, both layers have not been cut yet, so the distance N when both layers were cut by 1500 μm as planned was obtained.
Since the steel sheet 1 does not form a low portion region with the first exposed portion 22, there is no value of the distance N.
In the steel plates 2 to 6, since the low portion region is formed by the shirring process, the width of the low portion region becomes the value of the distance M. Therefore, the distance N is a value obtained by subtracting the distance M from 1500 μm. Therefore, the distances N from the steel plate 2 to the steel plate 6 are 1200 μm, 1000 μm, 800 μm, 1000 μm, and 1000 μm, respectively.
In the steel sheet 7, since the low portion region was formed by the partial pressing method, the distance between the deepest portion of the low portion region and the edge of the plated steel sheet was subtracted from 1500 μm, and the value of half the width of the low portion region was further subtracted. The value of 500 μm is the distance N.
[0299]
The steel plate 1 in which the low portion region is not formed is a comparative example, and the steel plates 2 to 7 in which the low portion region is formed are invention examples (examples).
[0300]
Next, the aluminum plating layer and the intermetallic compound layer between the plated steel sheets were cut under the conditions shown in Table 10 from No. 1 to No. 10. Tailored blanks were manufactured by butt-welding plated steel sheets to each other. Then, the (static) tensile strength of the tailored blank and the post-painting corrosion resistance of the first weld metal portion of the hot press molded product were determined.
[0301]
[Table 10]
[0302]
The aluminum plating layer and the intermetallic compound layer were cut with an end mill. As the end mill, a tool bottom blade having a diameter of φ6 mm and a tip radius of 0.5 mm was used. The rotation speed of the end mill was set to 40,000 rpm and the cutting feed rate was set to 6 m / min so that a flat surface cutting of 1.5 mm could be obtained.
In Table 10, the set of steel plates, the cutting depth y (μm), the value of the ratio (y / t) of the cutting depth to the plate thickness according to the formula (34), the distance M, and the first weld metal with respect to the numbers 1 to 10. The concentration of aluminum contained in the part, the corrosion resistance after painting of the first weld metal part, the tensile strength, and the comprehensive judgment are shown.
[0303]
The fact that the set of steel plates for No. 1 is steel plates 1 means that the pair of steel plates 1 in Table 9 are used.
The set of steel plates for No. 2 and No. 3 is steel plates 1 to each other. The set of steel plates for No. 4 and No. 5 is two steel plates. The sets of steel plates for Nos. 6 to 10 are steel plates 3 to 7, respectively.
[0304]
The cutting depth y for No. 1 is 0 μm within the range of 1500 μm where the aluminum-plated layer and the intermetallic compound layer are to be cut without cutting the aluminum-plated layer and the intermetallic compound layer for each steel plate 1. It means that the aluminum plating layer and the intermetallic compound layer remain as they are.
The cutting depths y from No. 2 to No. 10 are 10 μm, 50 μm, 30 μm, 100 μm, 50 μm, 50 μm, 50 μm, 50 μm, and 50 μm, respectively. The first surface and the second surface of each plated steel sheet were cut at a cutting depth of y, respectively. However, since the low portion region is not formed on the second surface of the plated steel sheet, the second plated portion is not formed on the second surface of the plated steel sheet after cutting the second surface of the plated steel sheet.
[0305]
Since the total thickness of both layers of the steel plate 1 to the steel plate 7 is 30 μm, when the cutting depth y is 30 μm, the aluminum plating layer and the intermetallic compound layer are all cut without cutting the base steel plate. It will be done.
As a result, the values of the ratio (y / t) of the cutting depth to the plate thickness according to the equation (34) of Nos. 1 to 10 are 0.0%, 0.8%, 4.2%, and 2. It is 5%, 8.3%, 4.2%, 4.2%, 3.1%, 2.8%, 4.2%.
[0306]
The distance M means the distance from the edge of the steel sheet to the edge of the second plating portion on the opposite side of the edge of the steel sheet as described above.
In No. 1, the distance M is 1500 μm because the aluminum plating layer and the intermetallic compound layer remain as they are in the range of 1500 μm where the aluminum plating layer and the intermetallic compound layer are to be cut.
In No. 2, the distance M is 1500 μm because a part of both layers having a thickness of 30 μm before cutting remains.
In No. 3, the distance M is 0 μm because the aluminum plating layer and the intermetallic compound layer were all cut without forming the low portion region on the steel sheet 1.
From No. 4 to No. 10, the distances M are 270 μm, 0 μm, 240 μm, 470 μm, 270 μm, 290 μm, and 470 μm, respectively.
[0307]
The concentration of aluminum contained in the first weld metal part of Nos. 1 to 10 was measured using, for example, the above-mentioned electron probe microanalyzer. The aluminum concentrations of Nos. 1 to 10 are 1.52% (mass), 1.01%, 0.02%, 0.43%, 0.02%, 0.39%, 0.74%, and 0, respectively. It is .34%, 0.33%, 0.74%.
[0308]
(Corrosion resistance test after painting)
The first weld metal part was tested in the same manner as in Example 1 of the first aspect. The determination criteria are the same as in Example 1.
In No. 3 and No. 5, it was found that the evaluation of the corrosion resistance of the first weld metal portion after painting was "D" (inferior).
In Nos. 1, 2, 4, 6 to 10, it was found that the evaluation of the corrosion resistance of the first weld metal portion after painting was "A" (excellent).
[0309]
(Tensile Strength) From
the hot press-formed product obtained above, a dumbbell-shaped test piece having a welded portion was collected as a test piece for a tensile strength test.
The test piece had a parallel portion distance of 20 mm and a width of the parallel portion of 15 mm, and was collected so as to have a welding line at the center portion of the parallel portion over the entire width so as to be orthogonal to the longitudinal direction. A tensile strength test was conducted using this test piece.
-Judgment criteria-
A: Break at steel plate (base steel plate)
D: Break at weld metal part other than steel plate (base steel plate)
[0310]
In No. 1 and No. 2, the evaluation of tensile strength was found to be "D" (inferior).
In numbers 3 to 10, it was found that the evaluation of the tensile strength was "A" (excellent).
[0311]
When the evaluation of the corrosion resistance after painting of the first weld metal part is "A" and the evaluation of the tensile strength is "A", the evaluation of the comprehensive judgment is "A" (excellent). When at least one of the evaluation of the corrosion resistance after painting and the evaluation of the tensile strength of the first weld metal portion is "D", the evaluation of the comprehensive judgment becomes "D" (inferior).
It was found that the evaluation of the comprehensive judgment was "D" in the numbers 1 to 3 and 5, and the evaluation of the comprehensive judgment was "A" in the numbers 4 and 6 to 10.
[0312]
When a steel pipe is manufactured by welding the first weld metal portion formed when two steel plates having the same thickness are butt-welded to manufacture a tailored blank and the ends of an open pipe made of steel plates. In the formed third weld metal portion, the relationship between the specifications at the end of the steel sheet and the concentration of aluminum contained in the first and third weld metal portions becomes equal to each other. Therefore, in the first and second embodiments in which the thicknesses of the plated steel sheet 1 and the plated steel sheet 2 are equal to each other, the aluminum contained in the third weld metal portion when the steel sheet and the steel pipe are manufactured using the plated steel sheet. This is an example regarding the concentration. The same applies to the embodiment of No. 1 to No. 10 in the third aspect.
[0313]
Conventionally, when aluminum-plated steel sheets are butt-welded, an intermetallic compound is formed due to an increase in the aluminum content in the weld metal. When mechanical stress is applied here, it becomes the starting point of cracks and the strength of the tailored blank decreases. Alternatively, the aluminum dissolved in the weld metal inhibits the austenite transformation in the region in the heating step before the hot stamping, and reduces the strength of the hot stamping body. In the steel sheet according to the present disclosure, an exposed layer excluding the intermetallic compound layer is provided in the end region of the steel sheet. This exposed portion eliminates the presence of intermetallic compounds in the welded portion of the tailored blank after the steel plates are butt-welded, and prevents the above-mentioned decrease in strength.
[0314]
Further, according to the steel sheet according to the present disclosure, at the time of butt welding, all Al contained in the second plating portion (aluminum plating layer) provided on the edge side is introduced into the weld metal portion. That is, the aluminum concentration of the weld metal portion of the tailored blank is adjusted by the amount of Al in the second plating portion. This improves the corrosion resistance of the weld metal. In other words, the aluminum concentration in the weld metal portion of the tailored blank can be adjusted only by adjusting the size of the second plating portion, and the corrosion resistance can be easily controlled. Further, since the second plating portion of the present disclosure includes an aluminum plating layer, a large size is not required. For example, even if the width of the second plating portion is less than half the width of the weld metal portion formed on the tailored blank (for example, 500 μm), sufficient Al is provided in the weld metal portion to improve the corrosion resistance of the weld metal portion. Can be introduced in.
[0315]
According to the present disclosure, all of the second plated portion is incorporated into the weld metal portion, and the first exposed portion adjacent to the second plated portion is an exposed portion between the weld metal portion and the first plated portion in the tailored blank. It becomes. That is, by providing the first exposed portion at a position adjacent to the second plating portion including the aluminum plating layer, a desired amount of Al is added to the weld metal portion by simply performing butt welding, and at the same time, the weld metal is welded. It is possible to form a first exposed portion between the portion and the first plating portion. That is, by butt welding the steel plates of the present disclosure, it is possible to form a tailored blank having excellent corrosion resistance and strength.
Industrial applicability
[0316]
Steel plate, tailored blank, hot press molded product, steel pipe, hollow hardened product, steel plate manufacturing method, tailored blank manufacturing method, hot press molded product manufacturing method, steel pipe manufacturing method, and hollow shape of the present disclosure. The method for producing a hardened molded product can be suitably used for maintaining the corrosion resistance and fatigue strength of the welded metal portion after coating.
Description of the sign
[0317]
12,112,212,512 Base steel plate 14,114
Aluminum plating layer 16,16 Intermetallic
compound layer
22,122 First exposed part
23 Second exposed part
24,124 Second plating part
26,126 First plating part
100 , 102, 103, 104, 110, 120, 200 Steel plate
100A Edge edge
150 First weld metal part
222 Third exposed part
226,526 Intermetallic compound part
250 Second weld metal part
300 Tailored blank
312 Third weld metal part
522 4th exposed part
F1 1st direction
F3 2nd direction
G 1 virtual line
G 2 virtual line
T1 virtual surface
T2 virtual surface
R2, R3, R7, R8 low part region
S11 steel plate manufacturing process (steel plate manufacturing method)
S12 Galvanized steel sheet manufacturing process
S14 Removal process
S15 Low part forming process
S17 Cutting process (deletion process)
Z 1 1st end
Z 2 2nd end
The scope of the claims
[Claim 1]
A
first plating portion in which an intermetallic compound layer and an aluminum plating layer are provided in order from the base steel plate side on the surface of the base steel plate and the base steel plate, and
a first exposed portion where the base steel plate is exposed. A
second plated portion provided with an intermetallic compound layer and an aluminum plating layer in this order from the base steel sheet side on the surface of the base steel sheet , and is perpendicular to the thickness direction of
the
steel sheet, and the first In the first direction from the plated portion toward one edge of the steel sheet, the first plated portion, the first exposed portion, the second plated portion, and the steel plate are on one surface of the base steel sheet. The edge is arranged in this order,
and at least the first plating portion, the first exposed portion, and the edge of the steel plate are arranged in this order on the other surface of the base steel plate in the first direction. in is arranged,
the first direction, and, when viewed from each cross section parallel to the thickness direction of the steel sheet,
from the boundary between the second plating section and said first exposed portion and extending in the first direction virtual A steel sheet in which the second plated portion is provided in a low portion region on the surface of the base steel sheet, which is located on the inner side of the base steel sheet in the thickness direction of the steel sheet with respect to the wire.
[Claim 2]
A
first plated portion in which an intermetallic compound layer and an aluminum plating layer are provided in this order from the base steel plate side on the surface of the base steel plate and the base steel plate, and a
first exposed portion where the base steel plate is exposed. A
second plated portion provided with an intermetallic compound layer and an aluminum plating layer in this order from the base steel sheet side on the surface of the base steel sheet , and is perpendicular to the thickness direction of
the
steel sheet. On one surface of the base steel sheet in the first direction from the one plated portion toward one edge of the steel sheet, the first plated portion, the first exposed portion, the second plated portion, and the steel plate The edge is arranged in this order, and in
the first direction, at least the first plating portion, the first exposed portion, and the edge of the steel plate are placed on the other surface of the base steel plate.
They are arranged in order
and extend in the first direction from the boundary between the first exposed portion and the second plated portion when viewed from a cross section parallel to the first direction and the thickness direction of the steel sheet . A steel plate in which the second plated portion is provided on the end surface of the base steel sheet, which is located on the virtual line or on the outer side from the inner side of the base steel sheet in the thickness direction from the virtual line toward the one surface. ..
[Claim 3]
The length from the surface of the second plating portion to the base steel plate in the thickness direction of the
steel plate is defined as the plating thickness, and the position of the boundary between the base steel plate and the intermetallic compound layer in the second plating portion is defined as the second plating thickness . The first end is
the position where the second plating portion is located farthest from the first exposed portion in
the first direction, and the first end and the second end along the first direction are defined as the second end. When the distance between the two is the width of the second plating portion, the
plating thickness at a position separated from the second end to a length of 20% of the width in the direction opposite to the first direction is
The steel sheet according to claim 1 or 2, which is thicker than the plating thickness at a position separated from the first end toward the first direction by a length of 10% of the width.
[Claim 4]
The steel sheet according to any one of claims 1 to 3, wherein the first exposed portion satisfies the following condition (A) and the following condition (B) when viewed from the cross section.
(A) The angle α formed by the following virtual line X and the following virtual line Y is 5.0 ° to 25.0 °.
(B) The maximum distance h in the vertical direction from the following virtual line Y toward the base steel plate is 1.0 μm to 5.0 μm.
Virtual line X: A virtual line in which the boundary line between the base steel plate and the metal-metal compound layer in the first plating portion is extended in the first direction.
Virtual line Y: From the virtual line X to the base steel plate. From the intersection of the vertical line of the virtual line X and the base steel plate, where the distance from the boundary point between the first exposed portion and the first plating portion on the virtual line X is 0.1 mm. A virtual line connecting the intersection of the vertical line and the base steel plate with the boundary point between the first exposed portion and the first plating portion.
[Claim 5]
The steel sheet according to claim 4, wherein the first exposed portion satisfies the following condition (C).
(C) Of the depth in the thickness direction of the steel sheet from the virtual line extending the surface of the aluminum plating layer in the first direction to the surface of the base steel sheet, the depth is 0.1 mm of the virtual line X. When the depth of the first exposed portion on the edge side of the steel sheet from the above point is D (μm), the D satisfies the following formula (1-1).
D ≦ (thickness of base steel plate in the first plating part mm × 0.2) / 2 ... (1-1)
[Claim 6]
The steel sheet according to claim 4 or 5, wherein the first exposed portion satisfies the following condition (D).
(D) The radius of curvature R 0 measured based on the following three points is 260 μm or more.
First point: Boundary point between the first exposed portion and the first plating portion
Second point: Intersection point between the vertical line of the virtual line X from the point of 0.1 mm and the base steel plate
Third point: The maximum distance point at which the vertical distance from the virtual line Y to the base steel plate is the maximum value.
[Claim 7]
A claim in which the first plating portion, the first exposed portion, the second plating portion, and the edge of the steel plate are arranged in this order on the other surface of the base steel plate in the first direction. Item 5. The steel sheet according to any one of Items 1 to 6.
[Claim 8]
The steel sheet according to any one of claims 1 to 7, wherein in the first direction, the second plating portion exists in a range of 0.9 mm from the edge of the steel sheet.
[Claim 9]
The steel sheet according to any one of claims 1 to 8, wherein the width of the first exposed portion in the first direction is 0.1 mm or more and 5.0 mm or less.
[Claim 10]
The base steel plate is based on mass%,
C: 0.02% to 0.58%,
Mn: 0.20% to 3.00%,
Al: 0.005% to 0.06%,
P: 0. 03% or less,
S: 0.010% or less,
N: 0.010% or less,
Ti: 0% to 0.20%,
Nb: 0% to 0.20%,
V: 0% to 1.0%,
W: 0% to 1.0%,
Cr: 0% to 1.0%,
Mo: 0% to 1.0%,
Cu: 0% to 1.0%,
Ni: 0% to 1.0%,
B: 0% to 0.0100%,
Mg: 0% to 0.05%,
Ca: 0% to 0.05%,
REM: 0% to 0.05%,
Sn: 0% to 0.5%,
Bi:
0% ~ 0.05%, Si: 0% ~ 2.00%,
and
balance: steel sheet according to any one of claims 1 to 9, having a chemical composition consisting of Fe and impurities.
[Claim 11]
Any of claims 1 to 10, wherein the average thickness of the aluminum plating layer in the first plating portion is 8 μm to 50 μm, and the average thickness of the intermetallic compound layer in the first plating portion is 1 μm to 10 μm. The steel plate according to item 1.
[Claim 12]
The area Samm 2 of the second plating portion in the cross section parallel to the first direction and the thickness direction of the steel plate and the thickness tbmm of the base steel plate of the first exposed portion of the steel plate are the equation (2). The steel sheet according to any one of claims 1 to 11.
Sa ≧ 8.51 × 10 -4 × tb ・ ・ ・ (2)
[Claim 13]
The steel sheet according to any one of claims 1 to 12, wherein the edge of the steel sheet and the second plating portion are adjacent to each other in the first direction.
[Claim 14]
The steel plate according to any one of claims 1 to 12, wherein in the first direction, a second exposed portion is provided between the edge of the steel plate and the second plated portion to expose the base steel plate. ..
[Claim 15]
In a tailored blank including a first weld metal portion and at least one steel plate portion connected to another steel plate portion via the first weld metal portion, the at
least one steel plate portion is
a surface of a base steel sheet. above, the base material steel plate intermetallic compound in this order from the side layer, and the first plating section aluminum layer is provided,
a first exposed portion to which the base steel sheet is exposed,
provided with,
in each steel sheet portions, The first plating portion and the first plating portion are formed on both surfaces of the base steel plate in a second direction which is perpendicular to the thickness direction of each steel plate portion and is directed from the first plating portion to the first weld metal portion. A
tailored blank in which the exposed portion and the first weld metal portion are arranged on the same surface in this order, and the aluminum concentration of the first weld metal portion is higher than the aluminum concentration of the steel plate portion.
[Claim 16]
The first exposed portion when viewed from a cross section perpendicular to the thickness direction of the steel plate and parallel to the second direction from the first plating portion to the first weld metal portion and the thickness direction of the steel plate portion. The tailored blank according to claim 15, which satisfies the following condition (A) and the following condition (B).
(A) The angle α formed by the following virtual line X and the following virtual line Y is 5.0 ° to 25.0 °.
(B) The maximum distance h in the vertical direction from the following virtual line Y toward the base steel plate is 1.0 μm to 5.0 μm.
Virtual line X: A virtual line in which the boundary line between the base steel plate and the metal-metal compound layer in the first plating portion is extended in the second direction.
Virtual line Y: From the virtual line X to the base steel plate. From the intersection of the vertical line of the virtual line X and the base steel plate, where the distance from the boundary point between the first exposed portion and the first plating portion on the virtual line X is 0.1 mm. A virtual line connecting the intersection of the vertical line and the base steel plate with the boundary point between the first exposed portion and the first plating portion.
[Claim 17]
The tailored blank according to claim 16, wherein the first exposed portion satisfies the following condition (C).
(C) Of the depth in the thickness direction of the steel sheet from the virtual line extending the surface of the aluminum plating layer in the second direction to the surface of the base steel sheet, the depth is 0.1 mm of the virtual line X. When the depth of the first exposed portion on the side of the first weld metal portion from the above point is D (μm), the D satisfies the following formula (1-1).
D ≦ (thickness of base steel plate in the first plating part mm × 0.2) / 2 ... (1-1)
[Claim 18]
The tailored blank according to claim 16 or 17, wherein the first exposed portion satisfies the following condition (D).
(D) The radius of curvature R 0 measured based on the following three points is 260 μm or more.
First point: Boundary point between the first exposed portion and the first plating portion
Second point: Intersection point between the vertical line of the virtual line X from the point of 0.1 mm and the base steel plate
Third point: The maximum distance point at which the vertical distance from the virtual line Y to the base steel plate is the maximum value.
[Claim 19]
The tailored blank according to any one of claims 15 to 18, wherein the concentration of aluminum contained in the first weld metal portion is 0.065% by mass to 1% by mass.
[Claim 20]
The first intermetallic compound portion in which the first intermetallic compound layer is provided on the surface of the first base metal steel plate, the third exposed portion in which the first base metal steel plate is exposed, the second weld metal portion, and the second The fourth exposed portion where the two base metal steel plates are exposed and the second intermetallic compound portion in which the second intermetallic compound layer is provided on the surface of the second base metal steel plate are the said ones of the first base metal steel plate. Arranged in this order along the surface and the surface of the second base
metal plate, the aluminum concentration of the second weld metal portion is higher than the aluminum concentration of each of the first base material steel plate and the second base metal steel plate. High hot press molded product.
[Claim 21]
The third exposed portion when viewed from a cross section perpendicular to the thickness direction of the steel plate and the thickness direction of the steel plate and parallel to the second direction from the first intermetallic compound portion to the second weld metal portion. The hot press-formed product according to claim 20, wherein the product satisfies the following condition (A) and the following condition (B).
(A) The angle α formed by the following virtual line X and the following virtual line Y is 5.0 ° to 25.0 °.
(B) The maximum distance h in the vertical direction from the following virtual line Y toward the first base steel sheet is 1.0 μm to 5.0 μm.
Virtual line X:
Virtual line Y: The virtual line X in which the boundary line between the first base metal steel plate and the first intermetallic compound layer in the first intermetallic compound portion is extended in the second direction. The intersection of the perpendicular line of the virtual line X from the first base material steel plate to the first base material steel plate and the boundary point between the third exposed portion and the first intermetallic compound portion in the virtual line X. A virtual line connecting the intersection of the perpendicular line and the first base steel plate from a point where the distance from the distance is 0.1 mm and the boundary point between the third exposed portion and the first intermetallic compound portion.
[Claim 22]
The hot press-molded product according to claim 21, wherein the third exposed portion satisfies the following condition (C).
(C) Of the depth in the thickness direction of the steel sheet from the virtual line extending the surface of the first intermetallic compound layer in the second direction to the surface of the first base steel sheet, the virtual line X When the depth of the third exposed portion on the side of the second weld metal portion from the point of 0.1 mm is D (μm), the D satisfies the following formula (1-2).
D ≦ (thickness of first base steel sheet in first intermetallic compound part mm × 0.2) / 2 ... (1-2)
[Claim 23]
The hot press-molded product according to claim 21 or 22, wherein the third exposed portion satisfies the following condition (D).
(D) The radius of curvature R 0 measured based on the following three points is 260 μm or more.
First point: Boundary point between the third exposed portion and the first intermetallic compound portion
Second point: The intersection of the perpendicular line of the virtual line X from the point of 0.1 mm and the first base metal steel plate.
Third point: The maximum distance point at which the vertical distance from the virtual line Y to the first base steel plate is the maximum value.
[Claim 24]
It includes a third welded metal portion and a third steel plate in which two peripheral ends are formed in an open tubular shape facing each other and the two ends are connected to each other via the third welded metal portion. In the steel pipe,
each of the two end portions of the third steel plate includes a
first plating portion in which an intermetal compound layer and an aluminum plating layer are provided on both surfaces of the base steel plate in order from the base steel plate side. A
first exposed portion from which the base steel plate is exposed
is provided, and
the first plating portion, the first exposed portion, and the third welded metal portion are arranged in this order in the circumferential direction
. 3 A steel pipe in which the aluminum concentration of the weld metal portion is higher than the aluminum concentration of the base steel sheet.
[Claim 25]
When viewed from a cross section perpendicular to the thickness direction of the steel plate and the thickness direction of the steel plate and parallel to the second direction from the first plating portion to the third weld metal portion,
the first exposed portion has the following conditions. The steel pipe according to claim 24, which satisfies (A) and the following condition (B).
(A) The angle α formed by the following virtual line X and the following virtual line Y is 5.0 ° to 25.0 °.
(B) The maximum distance h in the vertical direction from the following virtual line Y toward the base steel sheet is 1.0 μm to 5.0 μm.
Virtual line X: A virtual line in which the boundary line between the base steel plate and the metal-metal compound layer in the first plating portion is extended in the second direction.
Virtual line Y: From the virtual line X to the base steel plate. From the intersection of the vertical line of the virtual line X and the base steel plate, where the distance from the boundary point between the first exposed portion and the first plating portion on the virtual line X is 0.1 mm. A virtual line connecting the intersection of the vertical line and the base steel plate with the boundary point between the first exposed portion and the first plating portion.
[Claim 26]
The steel pipe according to claim 25, wherein the first exposed portion satisfies the following condition (C).
(C) Of the depth in the thickness direction of the steel sheet from the virtual line extending the surface of the aluminum plating layer in the second direction to the surface of the base steel sheet, the depth is 0.1 mm of the virtual line X. When the depth of the first exposed portion on the side of the third weld metal portion from the above point is D (μm), the D satisfies the following formula (1-1).
D ≦ (thickness of base steel plate in the first plating part mm × 0.2) / 2 ... (1-1)
[Claim 27]
The steel pipe according to claim 25 or 26, wherein the first exposed portion satisfies the following condition (D).
(D) The radius of curvature R 0 measured based on the following three points is 260 μm or more.
First point: Boundary point between the first exposed portion and the first plating portion
Second point: Intersection point between the vertical line of the virtual line X from the point of 0.1 mm and the base steel plate
Third point: The maximum distance point at which the vertical distance from the virtual line Y to the base steel plate is the maximum value.
[Claim 28]
The steel pipe according to any one of claims 24 to 27, wherein the concentration of aluminum contained in the third weld metal portion is 0.065% by mass to 1% by mass.
[Claim 29]
The third intermetallic compound portion in which the third intermetallic compound layer is provided on the surface of the third base metal steel plate, the fifth exposed portion in which the third base metal steel plate is exposed, and the aluminum concentration is 0.065% by mass. A fourth metal in which a third intermetallic compound layer is provided on the surface of the third weld metal portion of ~ 1% by mass, the sixth exposed portion where the fourth base metal steel plate is exposed, and the fourth base metal steel plate. The
intermetallic portions are arranged in this order along both surfaces of the third base metal steel plate and both surfaces of the fourth base metal steel plate, and the aluminum concentration of the third weld metal portion is determined. A hollow hardened molded product having a higher aluminum concentration than each of the third base metal steel plate and the fourth base metal steel plate.
[Claim 30]
When viewed from a cross section perpendicular to the thickness direction of the steel plate and the thickness direction of the steel plate and parallel to the second direction from the third intermetallic compound portion to the third weld metal portion,
the fifth exposed portion is The hollow hardened molded product according to claim 29, which satisfies the following condition (A) and the following condition (B).
(A) The angle α formed by the following virtual line X and the following virtual line Y is 5.0 ° to 25.0 °.
(B) The maximum distance h in the vertical direction from the following virtual line Y toward the third base steel sheet is 1.0 μm to 5.0 μm.
Virtual line X:
Virtual line Y: The virtual line X in which the boundary line between the third base metal steel plate and the third intermetallic compound layer in the third intermetallic compound portion is extended in the second direction. The intersection of the vertical line of the virtual line X from the third base material steel plate to the third base material steel plate and the boundary point between the fifth exposed portion and the third intermetallic compound portion in the virtual line X. A virtual line connecting the intersection of the perpendicular line and the third base steel plate from a point where the distance from the third base material is 0.1 mm and the boundary point between the fifth exposed portion and the third intermetallic compound portion.
[Claim 31]
The hollow hardened molded product according to claim 30, wherein the fifth exposed portion satisfies the following condition (C).
(C) Of the depth in the thickness direction of the steel sheet from the virtual line extending the surface of the third intermetallic compound layer in the second direction to the surface of the third base steel sheet, the virtual line X When the depth of the fifth exposed portion on the side of the third weld metal portion from the point of 0.1 mm is D (μm), the D satisfies the following formula (1-3).
D ≦ (thickness of the third base steel sheet in the third intermetallic compound part mm × 0.2) / 2 ... (1-3)
[Claim 32]
The hollow hardened molded product according to claim 30 or 31, wherein the fifth exposed portion satisfies the following condition (D).
(D) The radius of curvature R 0 measured based on the following three points is 260 μm or more.
First point: Boundary point between the fifth exposed portion and the third intermetallic compound portion
Second point: The intersection of the perpendicular line of the virtual line X from the point of 0.1 mm and the third base metal steel plate
Third point: The maximum distance point at which the vertical distance from the virtual line Y to the third base steel plate is the maximum value.
[Claim 33]
A step of providing a plated steel plate in which an intermetallizing compound layer and an aluminum plating layer are provided in this order on the surface of the base material steel plate from the base material steel plate side,
and removing a part of the aluminum plating layer and the intermetallizing compound layer. By doing so, the first exposed portion where the base metal steel plate is exposed, and the first plating portion where the metal-metal compound layer and the aluminum plating layer remain on the surface of the base material steel plate in this order from the base material steel plate side. A removal step of forming a second plating portion in which the intermetallic compound layer and the aluminum plating layer remain on the surface of the base metal steel plate
is performed, and in the
removal step, the plating steel plate is perpendicular to the thickness direction. In the first direction from the central portion of the plated steel plate to one edge of the plated steel plate in a plan view, the first plated portion and the first exposed portion are on one surface of the base metal steel plate. The second plated portion and the edge of the plated steel plate are arranged in this order,
and at least the first plated portion and the first exposed surface are placed on the other surface of the base steel plate in the first direction. A method for manufacturing a steel plate in which the portions and the edge of the plated steel plate are arranged in this order.
[Claim 34]
Prior to the removal step, the plated steel sheet is pressed or cut to deform a part of the plated steel sheet to form a low portion portion on the surface of the base steel sheet of the plated steel sheet. When the step is performed and the
direction perpendicular to the thickness direction of the plated steel sheet and from the central portion of the plated steel sheet to one edge of the plated steel sheet in a plan view is set as the first direction, the
low portion region Is from a virtual line extending in the first direction from the boundary between the first exposed portion and the second plated portion when viewed from a cross section parallel to the first direction and the thickness direction of the steel sheet.
Is also a region located on the inner side of the base steel sheet in the thickness direction of the plated steel sheet, and in the removing step, the aluminum plating layer existing at least outside the plated steel sheet in the thickness direction from the virtual surface and The method for producing a steel sheet according to claim 33, wherein the second plating portion is formed on the low portion region by removing the intermetallic compound layer.
[Claim 35]
The thickness of the aluminum-plated layer per side is a μm, the thickness of the
intermetallic compound layer per side is bμm,
the thickness of the plated steel sheet is tμm, and
the deepest low depth of the low region is xμm. The
low portion depth indicates the distance from the virtual line to the surface of the base steel plate in the low portion region
, and the depth of the region cut in the removal step in the thickness direction of the plated steel plate is yμm. The method for manufacturing a steel sheet according to claim 34, wherein the method (5) to (9) is satisfied
when the distance between the first plating portion and the second plating portion is N μm
.
9 ≦ a + b <60 ・ ・ (5)
2% ≦ (x / t) ≦ 15% ・ ・ (6)
a + b
Documents
Orders
Section
Controller
Decision Date
Application Documents
#
Name
Date
1
202017049673-IntimationOfGrant28-05-2024.pdf
2024-05-28
1
202017049673-TRANSLATIOIN OF PRIOIRTY DOCUMENTS ETC. [13-11-2020(online)].pdf
2020-11-13
2
202017049673-PatentCertificate28-05-2024.pdf
2024-05-28
2
202017049673-STATEMENT OF UNDERTAKING (FORM 3) [13-11-2020(online)].pdf
2020-11-13
3
202017049673-Written submissions and relevant documents [14-05-2024(online)].pdf
2024-05-14
3
202017049673-REQUEST FOR EXAMINATION (FORM-18) [13-11-2020(online)].pdf
2020-11-13
4
202017049673-PROOF OF RIGHT [13-11-2020(online)].pdf