Technical field
[0001]
The present invention is a steel plate, a tailored blank, a hot press molded product, a steel pipe, a hollow quenching molded product, a method for manufacturing a steel plate, a method for manufacturing a tailored blank, a method for manufacturing a hot press molded product, a method for manufacturing a steel pipe, and a hollow. The present invention relates to a method for manufacturing a hardened molded article.
This application is applied to Japanese Patent Application No. 2017-215747 filed in Japan on November 8, 2017, Japanese Patent Application No. 2018-167169 filed in Japan on September 6, 2018, and Japan on October 26, 2018. The priority right is claimed based on Japanese Patent Application No. 2018-202087, which is filed here, and the contents thereof are incorporated herein.
Background technology
[0002]
In recent years, in order to protect the global environment by reducing CO 2 gas emissions, reducing the weight of automobile bodies has become an urgent issue in the automobile field. In order to solve this problem, studies to apply high-strength steel sheets are being actively made. The strength of steel sheets (plated steel sheets) is becoming higher and higher.
[0003]
BACKGROUND ART Hot pressing (hereinafter, sometimes referred to as “hot stamp”) has been attracting attention as one of the techniques for molding automobile members. In hot stamping, a steel sheet is heated to a high temperature and press-formed in a temperature range of Ar 3 transformation temperature or higher. Further, in hot stamping, a press-formed steel sheet is rapidly cooled by heat removal by a mold, and a transformation is caused simultaneously with the forming under a press pressure. The hot stamping is a technique capable of producing a hot press molded product (hereinafter, also referred to as “hot stamped molded product”) having high strength and excellent shape fixability by the above steps.
[0004]
Further, in order to improve the yield and the functionality of press-formed parts for automobiles, a tailored blank in which at least two end faces of steel plates are butted and joined by laser welding, plasma welding or the like is applied as a press material. Has been done. In the tailored blank, since a plurality of steel plates are joined depending on the purpose, it is possible to freely change the plate thickness and strength within one component. As a result, by using the tailored blank, the functionality of the automobile member can be improved and the number of parts of the automobile member can be reduced. Further, by hot stamping the tailored blank, it is possible to manufacture a high-strength press-formed product in which the plate thickness, strength, etc. are freely changed.
[0005]
When an automobile member is formed by hot stamping using a tailored blank as a pressing material, the tailored blank is heated to a temperature range of 800° C. to 1000° C., for example. For this reason, a plated steel sheet plated with aluminum such as Al-Si having a high boiling point is often used for a tailored blank for hot stamping.
[0006]
Heretofore, as a steel plate for forming a tailored blank, for example, various steel plates for butt welding having a plating layer have been studied (see, for example, Patent Documents 1 to 5).
The steel plates for butt welding disclosed in Patent Documents 1 to 5 are base metal plates, aluminum plating layers provided on both sides of the base metal plate, and metal-metal formed between the base metal plate and the aluminum plating layer. And a compound layer.
[0007]
In the steel plate for butt welding disclosed in Patent Document 1, the aluminum plating layer in a predetermined range is removed from the edge of the steel plate for butt welding, and the intermetallic compound layer in the predetermined range is left. Then, adjacent to the predetermined range, a first plated portion in which an intermetallic compound layer and an aluminum plated layer are provided on the base material steel plate is formed. Laser processing is used to remove the aluminum plating layer.
In the butt-welding steel plates disclosed in Patent Documents 2 and 4, the aluminum plating layer and the intermetallic compound layer within the predetermined range are removed by a brush or laser processing.
[0008]
In the butt-welding steel sheet disclosed in Patent Document 3, a flat notch surface is formed on the butt-welding steel sheet, so that the butt-welding steel sheet gradually progresses from the middle portion of the butt-welding steel sheet toward the edge of the butt-welding steel sheet. First, the thickness of the aluminum plating layer becomes thin, and subsequently, the thickness of the intermetallic compound layer becomes thin. As a result, the base steel plate is exposed to the outside at the edge of the butt-welding steel plate.
In the steel plate for butt welding disclosed in Patent Document 5, aluminum plating is performed so that the angle β formed by the normal line of the surface of the base steel plate and the end faces of the aluminum plating layer and the intermetallic compound layer is 0° to 80°. The layer and the intermetallic compound layer have been removed. The base steel plate is exposed to the outside at the edge of the butt-welding steel plate. Laser processing is used to remove the aluminum plating layer and the intermetallic compound layer.
[0009]
In this kind of butt-welding steel sheet, tailored blanks, steel pipes, etc. are manufactured by butt-welding the ends of the butt-welding steel sheet from which the predetermined range has been removed. The tailored blank is processed into a hot press molded product, a hollow quenching molded product and the like.
For example, paragraph [0062] of Patent Document 1 discloses that the welded blank is corrosion resistant after heat treatment.
Prior art documents
Patent literature
[0010]
Patent Document 1: Japan Special Table 2009-534529 gazette
Patent Document 2: Japan Special Table 2015-525677 gazette
Patent Document 3: Japan Special Table 2015-523210 gazette
Patent Document 4: Japan Special Table 2015-536246 JP
Patent Document 5: Chinese Patent application Publication No. 106 334 875
Summary of the invention
Problems to be Solved by the Invention
[0011]
However, when a tailored blank is formed from a hot-dip aluminized steel sheet, a hard and brittle intermetallic compound layer exists in the plating layer, so that the intermetallic residue remaining at the boundary between the weld metal and the weld heat affected zone (stress concentration zone) It is affected by the compound layer. Therefore, in the hot press-formed product using the tailored blank, when the load is repeatedly applied, the fatigue strength of the welded metal portion decreases. Further, a large amount of Al in the hot-dip aluminized layer is dispersed in the weld metal portion, which causes a decrease in corrosion resistance, which becomes a problem.
On the other hand, in the butt-welding steel sheets of Patent Document 2 to Patent Document 5, the aluminum plating layer and the intermetallic compound layer in the welded portion to be welded are removed. For this reason, when a hot press-formed product manufactured from a butt-welding steel plate is painted, the adhesion of the paint on the surface of the weld metal part is reduced, and the post-coating corrosion resistance of the weld metal part is reduced.
[0012]
The subject of the present invention is a butt-welding steel plate, a tailored blank, a hot press-formed product, a steel pipe, and a hollow shape, which suppresses the decrease in fatigue strength while maintaining the corrosion resistance after coating of the weld metal portion formed during butt welding. The present invention provides a quench-formed product, a method for producing a steel plate for butt welding, a method for producing a tailored blank, a method for producing a hot press product, a method for producing a steel pipe, and a method for producing a hollow quench-formed product.
Means for solving the problem
[0013]
Means for solving the above problems include the following aspects.
[0014]
<1> A first plated portion in which an intermetallic compound layer and an aluminum plating layer are sequentially provided on the surface of a base material steel sheet from the base material steel sheet side, a first exposed portion where the base material steel sheet is exposed, and A second plated portion provided with the intermetallic compound layer and the aluminum plated layer in order from the base steel plate side on the surface of the base steel plate, and is perpendicular to the thickness direction of the steel plate, and In a first direction from the plated portion to one edge of the steel sheet, on at least one surface of the base steel sheet, the first plated portion, the first exposed portion, the second plated portion, the steel sheet The edges are arranged in this order, and in the first direction, on the other surface of the base material steel sheet, at least the first plated portion, the first exposed portion, the edge of the steel sheet, Steel plates arranged in order.
<2> In the first direction, the first plated portion, the first exposed portion, the second plated portion, and the edge of the steel sheet are arranged in this order on the other surface of the base material steel sheet. <1> The steel sheet according to <1>.
<3> The steel plate according to <1> or <2>, wherein in the first direction, the second plated portion exists within a range of 0.5 mm from the edge of the steel plate.
[0015]
<4> The base steel sheet is, in mass%, C: 0.02% to 0.58%, Mn: 0.20% to 3.00%, Al: 0.005% to 0.20%, 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%, Bi: 0% to 0.05%, Si: 0% to 2.00%, P: 0.03% or less, S:0 The steel sheet according to any one of <1> to <3>, having a chemical composition of 0.010% or less, N: 0.010% or less, and the balance: Fe and impurities.
<5> The average thickness of the aluminum plated layer in the first plated portion is 8 μm to 40 μm, and the average thickness of the intermetallic compound layer in the first plated portion is 3 μm to 10 μm. The steel plate according to any one of 4>.
[0016]
<6> The second plated portion is provided only on one surface of the steel sheet, and the width cμm of the second plated portion in the first direction and the thickness fμm of the aluminum plated layer in the second plated portion are ( The steel sheet according to any one of <2> to <4>, which satisfies the expression 1).
385.48f −0.914 ≦c≦500 (1)
<7> The second plated portions are provided on both surfaces of the steel plate, and the width cμm of the second plated portion in the first direction, and The steel plate according to any one of <2> to <4>, wherein a thickness f μm of the aluminum plated layer in the second plated portion satisfies the expression (2).
359.65f −1.129 ≦c≦9368f −0.904 •••　(2)
<8> In the first direction, the width of the second plated portion is smaller than the width of the first exposed portion <1. The steel plate of any one of <> to <7>.
[0017]
<9> In the lower part region of the surface of the base material steel plate, which is located on the inner side of the base material steel plate in the thickness direction than the virtual surface extending the surface of the first exposed portion in the first direction, The steel sheet according to any one of <1> to <8>, in which a second plated portion is provided.
<10> The steel sheet according to any one of <1> to <9>, in which the edge of the steel sheet and the second plated portion are adjacent to each other in the first direction.
<11> Any one of <1> to <9>, including a second exposed portion where the base steel sheet is exposed between the edge of the steel sheet and the second plated portion in the first direction. The steel plate according to item.
[0018]
<12> The steel plate according to <11>, wherein the width of the second exposed portion is smaller than the width of the first exposed portion in the first direction.
<13> The steel sheet according to <11> or <12>, wherein the width of the second exposed portion is 0.01 mm or more and the width of the first exposed portion is 0.05 mm or more in the first direction.
<14> In a tailored blank including a first weld metal part and at least two steel plate parts connected via the first weld metal part, each of the at least two steel plate parts is a surface of a base metal plate. An intermetallic compound layer, a first plated portion provided with an aluminum plating layer in order from the base material steel plate side, and a first exposed portion where the base material steel plate is exposed are provided on each of the steel plate portions. In the second direction which is perpendicular to the thickness direction of each of the steel plate portions and extends from the first plated portion to the first weld metal portion, the first plated portion and the first plated portion are formed on both surfaces of the base material steel sheet. A tailored blank in which the exposed portion and the first weld metal portion are arranged on the same surface in this order.
[0019]
<15> The tailored blank according to <14>, wherein the aluminum concentration contained in the first weld metal part is 0.05% by mass to 1% by mass.
<16> A first intermetallic compound part in which a first intermetallic compound layer is provided on the surface of the first base material steel plate, a third exposed part in which the first base material steel plate is exposed, and an aluminum concentration contained therein. Of the second base metal steel sheet, a second weld metal part having a content of 0.05 mass% to 1 mass%, a fourth exposed part of the second base material steel plate, and a second intermetallic compound layer on the surface of the second base material steel plate. A hot press-formed product in which the provided second intermetallic compound portion is arranged in this order along the surface of the first base material steel plate and the surface of the second base material steel plate.
<17> A third weld metal part, and a third steel plate which is formed in an open tubular shape in which two end parts in the circumferential direction face each other, and the two end parts are connected to each other via the third weld metal part. In the steel pipe including, a first intermetallic compound layer and an aluminum plating layer are provided on each of the two end portions of the third steel plate on both surfaces of the base material steel plate in order from the base material steel plate side. A first exposed portion where the base steel plate is exposed, and the first plated portion, the first exposed portion, and the third weld metal portion are arranged in this order in the circumferential direction. Steel pipe.
[0020]
<18> The steel pipe according to <17>, wherein the aluminum concentration contained in the third weld metal part is 0.05% by mass to 1% by mass.
<19> A third intermetallic compound part in which a third intermetallic compound layer is provided on the surface of the third base material steel plate, a fifth exposed part in which the third base material steel plate is exposed, and an aluminum concentration contained. Of the third base metal steel sheet, a third weld metal part whose content is 0.05 mass% to 1 mass%, a sixth exposed portion where the fourth base material steel plate is exposed, and a fourth intermetallic compound layer on the surface of the fourth base material steel plate A hollow quench-formed product in which the provided fourth intermetallic compound portion is arranged in this order along each of both surfaces of the third base material steel plate and each of both surfaces of the fourth base material steel plate. ..
[0021]
<20> A plated steel sheet manufacturing step of manufacturing a plated steel sheet in which an intermetallic compound layer and an aluminum plated layer are sequentially provided on the surface of a base steel sheet from the side of the base steel sheet, the
aluminum plated layer and the intermetallic compound By removing a part of the layer, the first exposed portion exposing the base material steel plate, and the intermetallic compound layer and the aluminum plating layer on the surface of the base material steel plate in order from the base material steel plate side. And a second plating portion where the intermetallic compound layer and the aluminum plating layer remain on the surface of the base material steel sheet are removed, and a steel sheet is manufactured. In the removing step, in the first direction, which is perpendicular to the thickness direction of the plated steel sheet and extends from the central portion of the plated steel sheet to one edge of the plated steel sheet in the plan view, On at least one surface of the base steel plate, the first plated portion, the first exposed portion, the second plated portion, the edge of the plated steel plate is arranged in this order, in the first direction A method for manufacturing a steel sheet, wherein at least the first plated portion, the first exposed portion, and the edge of the plated steel sheet are arranged in this order on the other surface of the base steel sheet.
<21> In the removing step, the first plating portion, the first exposed portion, the second plating portion, the edge of the plated steel sheet on the other surface of the base steel sheet in the first direction. The method for producing a steel sheet according to <20>, which is arranged in this order.
[0022]
<22> The method for producing a steel sheet according to <20> or <21>, wherein in the removing step, a step of mechanically removing the aluminum plating layer and the intermetallic compound layer is performed.
<23> The method for producing a steel sheet according to <22>, wherein in the mechanically removing step, a removing step of removing the aluminum plating layer and the intermetallic compound layer by cutting or grinding is performed.
<24> The method for manufacturing a steel sheet according to <23>, wherein in the removing step, the aluminum plating layer and the intermetallic compound layer are removed by cutting with an end mill.
[0023]
<25> In the mechanically removing step, the plated steel sheet is cut or pressed to partially deform the plated steel sheet and the surface of the base steel sheet of the plated steel sheet before the removing step. A lower part forming step of forming a lower part region in the direction of the thickness of the plated steel plate is perpendicular to the direction from the central part of the plated steel plate to one edge of the plated steel plate in a plan view. Direction, the lower region is the interior of the base material steel sheet in the thickness direction of the plated steel sheet rather than an imaginary plane that extends the surface of the base material steel sheet that is not deformed in the first direction. The region located on the side, in the removing step, by cutting the aluminum plating layer and the intermetallic compound layer present outside the plated steel sheet in at least the thickness direction than the virtual surface, the lower region The method for producing a steel sheet according to <23> or <24>, wherein the second plating layer is formed on the steel sheet.
[0024]
<26> The thickness per one surface of the aluminum plating layer is a μm, the thickness per one surface of the intermetallic compound layer is b μm, the thickness of the plated steel sheet is t μm, and the deepest bottom depth of the lower region is Is x μm, the lower part depth indicates the distance from the virtual surface to the surface of the base material steel plate in the lower part region, and the depth of the region cut in the deleting step in the thickness direction of the plated steel plate. The thickness is y μm, and the distance between the first plated portion and the second plated portion is N μm, the method for producing a steel sheet according to <25>, which satisfies the expressions (5) to (9).
10≦a+b<50 •••(5)
2%≦(x/t)≦15% ••(6)
a+b In the lower portion forming step, the steel sheet according to <25> or <26> is formed by cutting the plated steel sheet by shirring or blanking to form the lower portion region. Method.
[0025]
<28> The method for producing a steel sheet according to any one of <25> to <27>, wherein in the low portion forming step, the low area is formed on both surfaces of the plated steel sheet.
<29> At least two steel plates, wherein at least one of the at least two steel plates is the steel plate according to any one of <1> to <13>. A butt welding of the steel plates of No. 2, and manufacturing a tailored blank in which the at least two steel plates are connected via a first weld metal part, wherein the second of the steel plates is the steel plate. A method for manufacturing a tailored blank, in which an edge having a plated portion is butt-welded, and all of the second plated portion melted in the butt-welding is taken into the first weld metal portion.
[0026]
<30> A method for producing a hot press-formed product, comprising hot-press forming the tailored blank according to <14> or <15> to produce a hot-press formed product.
<31> In the steel sheet according to any one of <1> to <13>, two end portions in the circumferential direction face each other, and the second plated portion is provided on at least one of the two end portions. It is formed in an open tubular shape so as to be arranged, the two ends of the steel plate are butt-welded to connect the two ends via a second weld metal portion, and the first melted when butt-welding is performed. 2 A method for manufacturing a steel pipe, wherein all the plated parts are incorporated in the second weld metal part.
<32> A method for producing a hollow quenching molded product, comprising quenching the steel pipe according to <17> or <18> to manufacture a hollow quenching molded product.
Effect of the invention
[0027]
Butt welding steel plate of the present invention, tailored blank, hot press molded product, steel pipe, hollow quenching molded product, butt welding steel plate manufacturing method, tailored blank manufacturing method, hot press molded product manufacturing method, steel pipe According to the manufacturing method and the method for manufacturing a hollow quenching-molded product, it is possible to suppress deterioration in fatigue strength while maintaining the post-painting corrosion resistance of the weld metal portion formed during butt welding.
Brief description of the drawings
[0028]
FIG. 1 is a schematic cross-sectional view showing an example of an end portion having a first exposed portion and a second plated portion of a base steel sheet in a butt-welding steel sheet according to the first aspect of the present disclosure.
FIG. 2 is a schematic cross-sectional view showing another example of an end portion having a first exposed portion and a second plated portion of a base steel sheet in a butt-welding steel sheet according to the first aspect of the present disclosure.
FIG. 3 is a schematic cross-sectional view showing another example of an end portion having a first exposed portion and a second plated portion of a base steel sheet in a butt-welding steel sheet according to the first aspect of the present disclosure.
FIG. 4 is a cross-sectional photograph showing an example of an end portion having a first exposed portion and a second plated portion of the base steel sheet in the butt-welding steel sheet according to the first aspect of the present disclosure.
FIG. 5 is a perspective view of a steel pipe according to a first aspect of the present disclosure.
FIG. 6 is a schematic plan view illustrating the method for manufacturing the steel pipe of the first aspect of the present disclosure.
FIG. 7 is a schematic perspective view illustrating the method for manufacturing the steel pipe according to the first aspect of the present disclosure.
FIG. 8 is a schematic cross-sectional view showing a state where two steel plates for butt welding according to the first aspect of the present disclosure are opposed to each other.
FIG. 9 is a schematic cross-sectional view showing a tailored blank of the first aspect of the present disclosure.
FIG. 10 is a diagram showing a trial calculation result of the concentration of aluminum contained in the first weld metal portion with respect to the width of the second plated portion.
FIG. 11 is a diagram showing the relationship between the width of the second plated portion and the concentration of aluminum contained in the first weld metal portion when the second plated portion is formed on only one surface and the thickness of the aluminum plated layer is 13 μm. Is.
[FIG. 12] Thickness of an aluminum plating layer so that the concentration of aluminum contained in the first weld metal portion becomes 0.05% by mass and 1% by mass when the second plated portion is formed on only one surface. It is a figure which shows the relationship between the width of the 2nd plating part.
FIG. 13 shows the thickness of the aluminum plating layer for the aluminum concentration in the first weld metal portion to be 0.05% by mass and 1% by mass when the second plated portion is formed on both sides. It is a figure which shows the relationship with the width of a 2nd plating part.
FIG. 14 is a cross-sectional photograph showing an example of a tailored blank after hot press forming.
FIG. 15 is a schematic cross-sectional view showing an example of an end portion having an exposed portion of a base steel sheet and a second plated portion in a butt-welding steel sheet according to a second aspect of the present disclosure.
FIG. 16 is a schematic cross-sectional view showing another example of the end portion having the exposed portion and the second plated portion of the base steel sheet in the butt-welding steel sheet according to the second aspect of the present disclosure.
FIG. 17 is a schematic cross-sectional view showing another example of the end portion having the exposed portion and the second plated portion of the base steel sheet in the butt-welding steel sheet of the second aspect of the present disclosure.
FIG. 18 is a cross-sectional photograph showing an example of an end portion having an exposed portion and a second plated portion of a base steel sheet in a butt-welding steel sheet according to a second aspect of the present disclosure.
FIG. 19 is a schematic enlarged cross-sectional view showing another example of the end portion having the exposed portion and the second plated portion of the base steel sheet in the butt-welding steel sheet of the second aspect of the present disclosure.
FIG. 20 is a schematic cross-sectional view showing an example of a tailored blank of a second aspect of the present disclosure.
FIG. 21 is a schematic cross-sectional view showing an example of a tailored blank manufactured by the method for manufacturing a tailored blank according to the third aspect of the present disclosure.
FIG. 22 is a schematic cross-sectional view showing an example of a butt-welding steel plate used in the method for manufacturing a tailored blank according to the third aspect of the present disclosure.
FIG. 23 is a flowchart showing a method for manufacturing a tailored blank according to the third aspect of the present disclosure.
FIG. 24 is a cross-sectional view illustrating a lower portion forming step in the method for manufacturing a tailored blank according to the third aspect of the present disclosure.
FIG. 25 is a cross-sectional view illustrating a lower part forming step in the method for manufacturing a tailored blank according to the third aspect of the present disclosure.
FIG. 26 is a cross-sectional photograph showing an example of a state in which a lower portion region is formed on the plated steel sheet according to the third aspect of the present disclosure.
FIG. 27 is a cross-sectional photograph showing an example of a state in which the first exposed portion and the second plated portion are formed on the butt-welding steel plate of the third aspect of the present disclosure.
FIG. 28 is a cross-sectional photograph showing an example of a state in which the first exposed portion and the second plated portion are formed on the butt-welding steel plate according to the third aspect of the present disclosure.
FIG. 29 is a cross-sectional view illustrating a lower part forming step in a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 30 is a cross-sectional view illustrating a cutting step in a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 31 is a cross-sectional view illustrating a lower portion forming step in a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 32 is a cross-sectional view illustrating a lower portion forming step in a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 33 is a cross-sectional view illustrating a cutting step in a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 34 is a flowchart showing a method for manufacturing a tailored blank of a modified example of the third aspect of the present disclosure.
FIG. 35 is a perspective view of a steel plate for butt welding according to the first aspect of the present disclosure.
FIG. 36 is a perspective view illustrating a step of a method for manufacturing a steel plate for butt welding according to the first aspect of the present disclosure.
FIG. 37 is a perspective view illustrating another step of the method for manufacturing the steel plate for butt welding according to the first aspect of the present disclosure.
[FIG. 38] In a butt-welding steel plate according to a second aspect of the present disclosure, (A) is a schematic cross-sectional view of an end portion, and (B) is a plan view.
FIG. 39 is a schematic cross-sectional view illustrating a step of forming an exposed portion and a second plated portion on the butt-welding steel plate according to the second aspect of the present disclosure.
MODE FOR CARRYING OUT THE INVENTION
[0029]
Hereinafter, an example of a preferable aspect of the present disclosure will be described in detail.
The steel sheet of the present disclosure is a steel sheet that forms a tailored blank by butt welding with another steel sheet, and will be described below as a butt welding steel sheet.
In the present specification, the numerical range represented by “to” means the range including the numerical values before and after “to” as the lower limit value and the upper limit value.
In the present specification, the content of the component (element) may be referred to as “C content” in the case of the content of C (carbon), for example. In addition, the contents of other elements may be similarly expressed.
In the present specification, the meaning of the term “process” is not limited to an independent process, and even if the process is not clearly distinguishable from other processes, the term is the term as long as the intended purpose of the process is achieved. Included in the meaning of.
[0030]
In the present disclosure, the terms "base material steel plate", "intermetallic compound layer", and "aluminum plating layer" define the ranges of "base material steel plate, intermetallic compound layer, and aluminum plating layer" described later in the first aspect. Will be explained.
In the present disclosure, the term “cross-section” of the butt-welding steel plate (steel plate) means a cross-section cut in the thickness (plate thickness) direction of the butt-welding steel plate. Specifically, in FIG. 1, the thickness direction of the butt-welding steel plate 100 is Z, and the direction in which the first exposed portion 22 extends (the direction orthogonal to the display surface in FIG. 1) is X. Then, the directions orthogonal to the directions Z and X are designated as Y. At this time, the cross section means a cross section cut along the YZ plane.
[0031]
In the present disclosure, the term “end surface” of the butt-welding steel sheet means a surface of the butt-welding steel sheet whose surfaces in the thickness direction are exposed between the surfaces facing each other in the thickness direction.
In the present disclosure, the term “edge” of the butt-welding steel sheet means a portion adjacent to the end surface of the butt-welding steel sheet.
In the present disclosure, the term “end portion” of the butt-welding steel plate is a region located around the butt-welding steel plate, and has a facing width of the butt-welding steel plate (that is, the facing edge to the end). The length up to the edge) means a region within 5% from the end face of the steel plate for butt welding.
The butt-welding steel sheet of the present disclosure forms a tailored blank by butt-welding the end surface of the end portion with the end surface of another butt-welding steel sheet. Here, as the aspect of the two butt-welding steel plates to be butt-welded, any aspect of a plurality of aspects described below can be adopted.
[0032]
(First aspect)

The steel sheet for butt welding of the present disclosure has a base material steel sheet, an intermetallic compound layer, and an aluminum plating layer. And the butt-welding steel plate of this indication has the 1st plating part in which the intermetallic compound layer and the aluminum plating layer were provided in order from the base material steel plate side on the surface of the base material steel plate. Moreover, the steel plate for butt welding of this indication has the 1st exposed part which exposed the base material steel plate. Further, the butt-welding steel sheet of the present disclosure has a second plated portion in which an intermetallic compound layer and an aluminum plating layer are provided on the surface of the base steel sheet in this order from the base steel sheet side.
[0033]
Here, the direction (Y direction) that is perpendicular to the thickness direction of the butt-welding steel plate and goes from the first plated portion to one edge of the butt-welding steel plate is referred to as a first direction (first direction). In the butt-welding steel sheet of the present disclosure, in the first direction, the first plated portion, the first exposed portion, the second plated portion, and the edge of the butt-welding steel sheet on the surface of at least one of the base material steel sheets are The first plated portion, the first exposed portion, the second plated portion, and the edge of the butt-welding steel plate are arranged in this order. In the butt-welding steel sheet of the present disclosure, at least the first plated portion, the first exposed portion, and the edge of the butt-welding steel sheet are arranged in this order on the other surface of the base steel sheet in the first direction. To be done.
In the first direction, it is preferable that the first plated portion, the first exposed portion, the second plated portion, and the edge of the butt-welding steel sheet are arranged in this order on the other surface of the base steel sheet. ..
The butt-welding steel sheet of the present disclosure is formed as a tailored blank by butt-welding the end surface of the end portion with the end surface of another steel sheet. The shape of the steel plate for butt welding is not particularly limited.
[0034]
FIG. 1 shows a first plated portion, a first exposed portion of a base steel sheet, and a second plated portion provided with an intermetallic compound layer and an aluminum plated layer on each of both sides of the steel plate for butt welding of the present disclosure. It is a schematic sectional drawing which shows an example of the edge part which has. FIG. 2 shows a first plated portion, a first exposed portion of a base material steel sheet, and a second plated portion provided with an intermetallic compound layer and an aluminum plated layer on each of both surfaces of the steel sheet for butt welding of the present disclosure. It is a schematic sectional drawing which shows another example of the edge part which has. That is, in FIG. 1 and FIG. 2, each of both surfaces of the butt-welding steel plate has a first plated portion, a first exposed portion, and a second plated portion, and the second plated portion has an intermetallic compound layer and an aluminum compound layer. An aspect in which a plating layer is provided is shown.
Further, FIG. 3 is a second plating in which a first plated portion, a first exposed portion of the base steel sheet, an intermetallic compound layer, and an aluminum plated layer are provided on one surface of the steel sheet for butt welding of the present disclosure. FIG. 5 is a schematic cross-sectional view showing an example of an end portion provided with a first plating portion and a first exposed portion on the other surface. That is, in FIG. 3, the first plating portion, the first exposed portion, and the second plating portion are provided on one surface of the butt-welding steel plate, and the intermetallic compound layer and the aluminum plating layer are provided in the second plating portion. Is provided. Further, the first plated portion and the first exposed portion are provided at the end portion on the other surface of the butt-welding steel sheet shown in FIG. 3, but the second plated portion is not provided and the first exposed portion is the end portion. It is extended to the edge of the section.
[0035]
1 to 3, 100 is a steel plate for butt welding, 12 is a base steel plate, 14 is an aluminum plating layer, 16 is an intermetallic compound layer, 22 is a first exposed portion, 24 is a second plating portion, and 26 is a second portion. 1 shows a plated part.
Moreover, 100A shows the edge of the steel plate 100 for butt welding. 100B indicates the edge of the first plated portion 26 on the boundary between the first plated portion 26 and the first exposed portion 22. 100C indicates the edge of the second plated portion 24 on the boundary between the second plated portion 24 and the first exposed portion 22.
[0036]
The butt-welding steel plate 100 of the present disclosure includes a base steel plate 12, an intermetallic compound layer 16, and an aluminum plating layer 14. Then, the butt-welding steel plate 100 of the present disclosure has the first plating part 26 in which the intermetallic compound layer 16 and the aluminum plating layer 14 are sequentially provided on the surface of the base steel plate 12 from the base steel plate 12 side. Further, the butt-welding steel plate 100 of the present disclosure has the first exposed portion 22 from which the base material steel plate 12 is exposed. Further, the butt-welding steel plate 100 of the present disclosure has the second plating part 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 are provided on the surface of the base material steel plate 12.
Here, the direction that is perpendicular to the thickness direction of the butt-welding steel plate 100 and that extends from the first plated portion 26 toward the one edge 100A of the butt-welding steel plate 100 is referred to as a first direction F1. In the steel plate 100 for butt welding of this indication, the 1st plating part 26, the 1st exposed part 22, the 2nd plating part 24, 100 A of edges of the steel plate 100 for butt welding are the 1st plating part 26 in the 1st direction F1. The first exposed portion 22, the second plated portion 24, and the edge 100A of the butt-welding steel plate 100 are arranged in this order on the same plane.
[0037]
The first exposed portion 22 is formed in a region from the edge 100B of the first plated portion 26 to the edge 100C of the boundary between the second plated portion 24 and the first exposed portion 22. The first exposed portion 22 is formed between the first plated portion 26 and the second plated portion 24.
The second plated portion 24 is formed in a region including the edge 100A of the steel plate 100 for butt welding. In the first direction F1, the edge 100A of the butt welding steel plate 100 and the second plated portion 24 are adjacent to each other. The second plated portion 24 is formed in a region between the edge 100A of the butt-welding steel plate 100 and the edge 100C at the boundary between the second plated portion 24 and the first exposed portion 22.
In addition, in the butt-welding steel plate 100 shown in FIG. 1 and FIG. There is.
[0038]
On the other hand, in the butt-welding steel plate 100 shown in FIG. 3, the second plated portion 24, the first exposed portion 22 and the first plated portion 26 are formed on one surface of the end portion of the butt-welding steel sheet 100. The first exposed portion 22 and the first plated portion 26 are formed on the other surface of the end portion. That is, in the butt-welding steel plate 100 shown in FIG. 3, one surface of the end portion of the butt-welding steel plate 100 has the second plated portion 24 and 1 Exposed portion 22 is formed. Further, on the other surface of the end portion of the butt-welding steel plate 100, the first exposed portion 22 is formed in a region from the edge 100A of the butt-welding steel plate 100 to the edge 100B of the first plated portion 26. ..
[0039]
In the butt-welding steel plate 100 of the present disclosure, as shown in FIG. 1, at the end of the butt-welding steel plate 100, the thickness of the base material steel plate 12 at the first exposed portion 22 where the base material steel plate 12 is exposed is It may be the same as the thickness of the base material steel plate 12 in the 1-plated portion 26. Further, in the butt welding steel plate 100 of the present disclosure, as shown in FIG. 2, the thickness of the base material steel plate 12 at the first exposed portion 22 where the base material steel plate 12 is exposed at the end of the butt welding steel plate 100 is The thickness may be smaller than the thickness of the base material steel plate 12 in the first plated portion 26.
[0040]
Although the butt-welding steel sheet of the present disclosure has been described above with reference to FIGS. 1 to 3, the butt-welding steel sheet of the present disclosure is not limited thereto.
[0041]
An
aluminum plating layer is provided on the surface of the base steel plate 12. The base steel sheet is not particularly limited as long as it is obtained by an ordinary method including a hot rolling step, a cold rolling step, a plating step and the like. The base steel sheet may be either a hot rolled steel sheet or a cold rolled steel sheet.
The thickness of the base material steel plate 12 may be any thickness according to the purpose and is not particularly limited. For example, the thickness of the base material steel plate 12 may be 0.8 mm or more as a total thickness of the plated steel plate after the aluminum plating (the steel plate before the first exposed portion 22 and the like are formed). Further, the thickness may be 1 mm or more. Moreover, the thickness of the base material steel plate 12 may be 4 mm or less, and may be 3 mm or less.
[0042]
The base material steel plate 12 means, for example, various properties related to mechanical deformation and fracture such as high mechanical strength (for example, tensile strength, yield point, elongation, drawing, hardness, impact value, fatigue strength, etc.). .) is preferably used.
[0043]
Examples of preferable chemical compositions of the base material steel sheet 12 include the following chemical compositions.
The base material steel plate 12 is, by mass%, C: 0.02% to 0.58%, Mn: 0.20% to 3.00%, Al: 0.005% to 0.20%, Ti: 0%. ~0.20%, Nb:0%~0.20%, V:0%~1.0%, W:0%~1.0%, Cr:0%~1.0%, Mo:0% ~1.0%, Cu:0%~1.0%, Ni:0%~1.0%, B:0%~0.0100%, Mg:0%~0.05%, Ca:0% ~0.05%, REM: 0% ~ 0.05%, Bi: 0% ~ 0.05%, Si: 0% ~ 2.00%, P: 0.03% or less, S: 0.010% Hereinafter, it has a chemical composition of N: 0.010% or less, and the balance: Fe and impurities.
In the following, “%” indicating the content of the component (element) means “mass %”.
[0044]
(C: 0.02% to 0.58%)
C is an important element that enhances the hardenability of the base steel sheet 12 and mainly determines the strength after quenching. Further, C is an element that lowers the A 3 point and accelerates the quenching treatment temperature. If the C content is less than 0.02%, the effect may not be sufficient. Therefore, the C content is preferably 0.02% or more. On the other hand, when the amount of C exceeds 0.58%, the toughness of the hardened part deteriorates significantly. Therefore, the C content is preferably 0.58% or less. Preferably, the C content is 0.45% or less.
[0045]
(Mn: 0.20% to 3.00%)
Mn is an extremely effective element for enhancing the hardenability of the base steel sheet 12 and stably securing the strength after quenching. If the Mn content is less than 0.20%, the effect may not be sufficient. Therefore, the Mn content is preferably 0.20% or more. Preferably, the Mn content is 0.80% or more. On the other hand, when the amount of Mn exceeds 3.00%, the effect is not only saturated, but rather it may be difficult to secure stable strength after quenching. Therefore, the Mn content is preferably 3.00% or less. Preferably, the amount of Mn is 2.40% or less.
[0046]
(Al: 0.005% to 0.20%)
Al functions as a deoxidizing element and has a function of soundening the base steel plate 12. If the amount of Al is less than 0.005%, it may be difficult to obtain the effect due to the above-mentioned action. Therefore, the Al amount is preferably 0.005% or more. On the other hand, if the amount of Al exceeds 0.20%, the effects due to the above-mentioned action are saturated, which is disadvantageous in terms of cost. Therefore, the Al content is preferably 0.20% or less.
[0047]
(Ti: 0% to 0.20%, Nb: 0% to 0.20%, V: 0% to 1.0%, W: 0% to 1.0%)
Ti, Nb, V, and W are , Is an element that promotes mutual diffusion of Fe and Al in the aluminum plating layer and the base material steel plate 12. Therefore, at least one kind or two or more kinds of Ti, Nb, V, and W may be contained in the base material steel plate 12. However, if 1) the Ti amount and the Nb amount exceed 0.20%, or 2) the V amount and the W amount exceed 1.0%, the effect due to the above-mentioned action is saturated, which is disadvantageous in terms of cost. Therefore, the Ti amount and the Nb amount are preferably 0.20% or less, and the V amount and the W amount are preferably 1.0% or less. The Ti amount and the Nb amount are preferably 0.15% or less, and the V amount and the W amount are preferably 0.5% or less. In order to obtain the effect of the above action more reliably, it is preferable to set the lower limits of the Ti amount and the Nb amount to 0.01% and the lower limits of the V amount and the W amount to 0.1%.
[0048]
(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% )
Cr, Mo, Cu, Ni, and B are effective elements for enhancing the hardenability of the base steel sheet 12 and stably securing the strength after quenching. Therefore, the base steel plate 12 may contain one or more of these elements. However, even if the content of Cr, Mo, Cu, and Ni exceeds 1.0% and the content of B exceeds 0.0100%, the above effect is saturated, which is disadvantageous in terms of cost. Therefore, the content of Cr, Mo, Cu, and Ni is preferably 1.0% or less. The B content is preferably 0.0100% or less, and more preferably 0.0080% or less. In order to obtain the above effect more reliably, it is preferable that the content of Cr, Mo, Cu, and Ni is 0.1% or more, and the content of B is 0.0010% or more.
[0049]
(Ca: 0% to 0.05%, Mg: 0% to 0.05%, REM: 0% to 0.05%)
Ca, Mg, and REM refine the morphology of inclusions in steel, It has the function of preventing the occurrence of cracks during hot press forming due to inclusions. Therefore, the base steel sheet 12 may contain one or more of these elements. However, if added excessively, the effect of refining the form of the inclusions in the base material steel plate 12 is saturated, and only the cost is increased. Therefore, the Ca content is 0.05% or less, the Mg content is 0.05% or less, and the REM content is 0.05% or less. In order to obtain the effect of the above action more reliably, it is preferable to satisfy any one of the amount of Ca of 0.0005% or more, the amount of Mg of 0.0005% or more, and the amount of REM of 0.0005% or more.
[0050]
Here, REM refers to the 17 elements of Sc, Y, and the lanthanoid, and the content of the REM refers to the total content of these elements. The lanthanoid is industrially added to the base steel plate 12 in the form of misch metal.
[0051]
(Bi: 0% to 0.05%)
Bi becomes a solidification nucleus in the solidification process of molten steel, and by suppressing the secondary arm spacing of dendrite, segregation of Mn and the like segregated within the secondary arm spacing of dendrite is suppressed. It is an element that has the action of Therefore, the base material steel plate 12 may contain Bi. Bi is effective in suppressing deterioration of toughness due to segregation of Mn, particularly in steel plates in which a large amount of Mn is often contained, such as steel plates for hot pressing. Therefore, it is preferable to include Bi in such a steel type.
However, even if Bi is added to the base material steel plate 12 in an amount of more than 0.05%, the effect of the above-mentioned action is saturated, and the cost is increased. Therefore, the Bi content is 0.05% or less. Preferably, the Bi amount is 0.02% or less. In order to obtain the effect of the above action more reliably, the Bi amount is preferably 0.0002% or more. More preferably, the Bi amount is 0.0005% or more.
[0052]
(Si: 0% to 2.00%)
Si is a solid solution strengthening element and can be effectively utilized when it is contained up to 2.00%. However, if Si is contained in the base material steel plate 12 in an amount of more than 2.00%, there is a concern that a defect may occur in the plating property. Therefore, when the base steel sheet 12 contains Si, the Si amount is preferably 2.00% or less. The preferable upper limit is 1.40% or less, and more preferably 1.00% or less. The lower limit is not particularly limited, but the lower limit is preferably 0.01% in order to obtain the effect of the above action more reliably.
[0053]
(P: 0.03% or less)
P is an element contained as an impurity. If P is contained excessively, the toughness of the base steel plate 12 is likely to decrease. Therefore, the P content is preferably 0.03% or less. Preferably, the P amount is 0.01% or less. The lower limit of the amount of P does not have to be specified in particular, but the lower limit is preferably 0.0002% from the viewpoint of cost.
[0054]
(S: 0.010% or less)
S is an element contained as an impurity. S forms MnS and has an action of embrittlement the base steel plate 12. Therefore, the S content is preferably 0.010% or less. A more desirable S amount is 0.004% or less. The lower limit of the amount of S does not have to be specified, but the lower limit is preferably 0.0002% from the viewpoint of cost.
[0055]
(N: 0.010% or less)
N is an element contained as an impurity in the base steel plate 12. Further, N is an element that forms inclusions in the base steel plate 12 and deteriorates the toughness after hot press forming. Therefore, the N content is preferably 0.010% or less. The amount of N is preferably 0.008% or less, and more preferably 0.005% or less. The lower limit of the amount of N does not need to be specified, but the lower limit is preferably 0.0002% from the viewpoint of cost.
[0056]
(Remainder) The
balance is Fe and impurities. Here, examples of the impurities include components contained in raw materials such as ores and scraps, or components mixed into the steel plate during the manufacturing process. Impurity means a component that is not intentionally included in the steel sheet.
[0057]
The
aluminum plating layer 14 is formed on both surfaces of the base material steel plate 12. The method for forming the aluminum plating layer 14 is not particularly limited. For example, the aluminum plating layer 14 is formed on both surfaces of the base material steel plate 12 by a hot dipping method (a method of immersing the base material steel plate 12 in a molten metal bath mainly containing aluminum to form an aluminum plating layer). Good.
[0058]
Here, the aluminum plating layer 14 is a plating layer mainly containing aluminum, and may contain aluminum in an amount of 50% by mass or more. Depending on the purpose, the aluminum plating layer 14 may contain an element other than aluminum (for example, Si), or may contain impurities that are mixed in during the manufacturing process or the like. Specifically, the aluminum plating layer 14 may have a chemical composition of, for example, 5% to 12% by mass of Si (silicon) with the balance being aluminum and impurities. Further, the aluminum plating layer 14 contains 5% to 12% of Si (silicon) and 2% to 4% of Fe (iron) by mass%, and the balance has a chemical composition of aluminum and impurities. Good.
When Si is contained in the aluminum plating layer 14 within the above range, deterioration of workability and corrosion resistance can be suppressed. Further, the thickness of the intermetallic compound layer can be reduced.
[0059]
The thickness of the aluminum plating layer 14 in the first plating portion 26 is not particularly limited, but for example, the average thickness is preferably 8 μm (micrometer) or more, and preferably 15 μm or more. The thickness of the aluminum plating layer 14 in the first plating portion 26 is, for example, preferably 40 μm or less in average thickness, preferably 35 μm or less, and more preferably 30 μm or less.
In addition, the thickness of the aluminum plating layer 14 represents the average thickness in the 2nd plating part 24 of the steel plate 100 for butt welding.
[0060]
The aluminum plating layer 14 prevents corrosion of the base material steel plate 12. In addition, when the base material steel plate 12 is processed by hot press forming, the aluminum plating layer 14 has a scale (iron content) due to oxidation of the surface of the base material steel plate 12 even if the base material steel plate 12 is heated to a high temperature. Compound) is prevented. Further, the aluminum plating layer 14 has a higher boiling point and melting point than the plating coating of an organic material and the plating coating of another metal material (for example, a zinc material). Therefore, when the hot press molded product is molded by the hot press molding, the coating does not evaporate, and thus the effect of protecting the surface is high.
[0061]
The aluminum plating layer 14 can be alloyed with the iron (Fe) in the base steel plate 12 by heating during hot dipping and hot press forming. Therefore, the aluminum plating layer 14 is not necessarily formed as a single layer having a constant composition, and includes a partially alloyed layer (intermetallic compound layer).
[0062]
The
intermetallic compound layer 16 is a layer formed at the boundary between the base material steel plate 12 and the aluminum plating layer 14 when aluminum plating is provided on the base material steel plate 12. Specifically, the intermetallic compound layer 16 is formed by a reaction between the iron (Fe) of the base steel plate 12 and a metal containing aluminum (Al) in a molten metal bath mainly containing aluminum. The intermetallic compound layer 16 is mainly formed of a plurality of types of compounds represented by Fe x Al y (x and y represent 1 or more). If the aluminum plating layer containing Si (silicon) is an intermetallic compound layer 16 is Fe x Al y and Fe x Al y Si z more of (x, y, z is 1 or more) is represented by compounds Is formed by.
[0063]
The thickness of the intermetallic compound layer 16 in the first plated portion 26 is not particularly limited, but for example, the average thickness is preferably 3 μm or more, and preferably 4 μm or more. Further, the thickness of the intermetallic compound layer 16 in the first plated portion 26 may be, for example, 10 μm or less in average thickness, and preferably 8 μm or less. The thickness of the intermetallic compound layer 16 represents the average thickness of the second plated portion 24.
The thickness of the intermetallic compound layer 16 can be controlled by the temperature and immersion time of the molten metal bath mainly containing aluminum.
[0064]
Here, the confirmation of the base material steel plate 12, the intermetallic compound layer 16, and the aluminum plating layer 14, and the measurement of the thicknesses of the intermetallic compound layer 16 and the aluminum plating layer 14 are performed by the following method.
[0065]
Cutting is performed so that the cross section of the butt welding steel plate 100 is exposed, and the cross section of the butt welding steel plate 100 is polished. The direction of the cross section of the exposed butt-welding steel plate 100 is not particularly limited. However, the cross section of the butt welding steel plate 100 is preferably a cross section orthogonal to the direction in which the first exposed portion 22 extends.
The polished cross section of the steel plate 100 for butt welding is subjected to line analysis from the surface of the steel plate 100 for butt welding to the base metal plate 12 by an electron beam microanalyzer (Electron Probe MicroAnalyzer: FE-EPMA) to determine the aluminum concentration and the iron concentration. taking measurement. The aluminum concentration and the iron concentration are preferably average values measured three times.
The measurement conditions are an acceleration voltage of 15 kV, a beam diameter of about 100 nm, an irradiation time of 1000 ms per point, and a measurement pitch of 60 nm. The measurement distance may be such that the thickness of the plating layer can be measured. For example, the measurement distance is about 30 μm to 80 μm in the thickness direction. The thickness of the base material steel plate 12 is preferably measured by an optical microscope.
[0066]
<
Definition of Ranges of Base Steel Plate, Intermetallic Compound Layer, and Aluminum Plating Layer> As a measured value of the aluminum concentration in the cross section of the steel plate 100 for butt welding (plated steel plate), the aluminum (Al) concentration is less than 2 mass %. It is determined that the region is the base material steel plate 12 and the region where the aluminum concentration is 2% by mass or more is the intermetallic compound layer 16 or the aluminum plating layer 14. Further, in the intermetallic compound layer 16 and the aluminum plating layer 14, the region where the iron (Fe) concentration exceeds 4 mass% is the intermetallic compound layer 16, and the region where the iron concentration is 4 mass% or less is the aluminum plating layer 14. To judge.
The distance from the boundary between the base steel plate 12 and the intermetallic compound layer 16 to the boundary between the intermetallic compound layer 16 and the aluminum plating layer 14 is the thickness of the intermetallic compound layer 16. The distance from the boundary between the intermetallic compound layer 16 and the aluminum plating layer 14 to the surface of the aluminum plating layer 14 is the thickness of the aluminum plating layer 14.
[0067]
The thickness of the aluminum plating layer 14 and the thickness of the intermetallic compound layer 16 are linearly analyzed from the surface of the butt-welding steel plate 100 to the surface of the base material steel plate 12 (boundary between the base material steel plate 12 and the intermetallic compound layer 16). , As follows.
For example, when measuring the thickness of the second plated portion 24, in the longitudinal direction of the first exposed portion 22 (for example, the X direction in FIG. 1, hereinafter referred to as the second direction), the total length of the second plated portion 24 (hereinafter referred to as the total length). The thickness of the aluminum plating layer 14 at 5 positions obtained by equally dividing the above is determined, and the value obtained by averaging the obtained values is defined as the thickness of the aluminum plating layer 14. The thickness is measured at a position that is ½ of the width of the second plated portion in the cross-sectional view of the five places (hereinafter, the thickness is similarly measured). At this time, the thickness of the aluminum plating layer 14 is determined according to the above-described determination criteria. When the first exposed portion is extended on a curved line, the thickness may be obtained at a position where the entire length along the curved line is divided into five.
Similarly, when measuring the thickness of the intermetallic compound layer 16, the total length of the intermetallic compound layer 16 (the same applies to the following definition of the total length) is equally divided into five parts in the second direction. The thickness of the compound layer 16 is obtained, and the value obtained by averaging the obtained values is used as the thickness of the intermetallic compound layer 16. At this time, the thickness of the intermetallic compound layer 16 is determined according to the above-described determination criteria.
[0068]
As
shown in FIG. 35, the first exposed portion 22 is formed on both surfaces of the end portion of the butt-welding steel plate 100 where welding is planned. The first exposed portion 22 is formed along the edge 100B of the first plated portion 26. That is, in the case where the second plated portion 24 is formed, the first exposed portion 22 is located at the end portion where welding is planned, from the edge of the boundary between the second plated portion 24 and the first exposed portion 22 to the first exposed portion 22. It is formed in the range up to the edge 100B of the 1 plated portion 26. Further, when the second plated portion 24 is not formed, the first exposed portion 22 is from the edge 100A of the steel plate 100 for butt welding to the edge 100B of the first plated portion 26 at the end where welding is planned. Is formed in the range of.
Here, referring to FIG. 3, when the second plated portion 24 is formed, the first exposed portion 22 is formed from the edge 100C of the boundary between the second plated portion 24 and the first exposed portion 22 to the first plated portion. It is formed in a range up to the edge 100B of 26. When the second plated portion 24 is not formed, the first exposed portion 22 is formed in the range from the edge 100A of the butt-welding steel plate 100 to the edge 100B of the first plated portion 26.
[0069]
The 1st exposed part 22 formed in both surfaces of the edge part of the butt-welding steel plate 100 should just be formed as follows. That is, the end of the butt-welding steel plate 100, which is scheduled to be welded, is butt-welded. After that, at the boundary between the weld metal portion (first weld metal portion) formed in the tailored blank (joint) and the butt welding steel plate 100, the aluminum plating layer 14 and the intermetallic compound layer 16 do not remain, The first exposed portion 22 is formed. In this state, the first exposed portion 22 is provided on both surfaces of the end portion of the butt-welding steel plate 100 along the edge of the first plated portion 26.
[0070]
The width of the first exposed portion 22 in the first direction F1 (the distance from the second plated portion 24 to the first plated portion 26 in the first direction F1; hereinafter, also simply referred to as the width of the first exposed portion 22) is on average. It is preferably 0.2 mm or more. The width of the first exposed portion 22 may be 5.0 mm or less on average. When the butt welding is laser welding, the width of the first exposed portion 22 is preferably 0.5 mm or more, and the width of the first exposed portion 22 is preferably 1.5 mm or less. When the butt welding is plasma welding, the width of the first exposed portion 22 is preferably 1.0 mm or more, and the width of the first exposed portion 22 is preferably 4.0 mm or less. By setting the width of the first exposed portion 22 to 0.2 mm or more and the width of the first exposed portion 22 to 4.6 mm or less (average), the fatigue strength of the tailored blank when a hot press-formed product is obtained. Is easily suppressed. For example, as for the width of the exposed portion, the width of the exposed portion is measured with a microscope from five sections k which are obtained by dividing the entire length of the exposed portion into five equal parts (hereinafter, the same method for measuring the width).
[0071]
Considering the mechanical strength of the tailored blank, the thickness of the base material steel plate 12 in the first exposed portion 22 is preferably in the range of 90% to 100% as the plate thickness ratio represented by the equation (11). When the plate thickness ratio is 90% or more, reduction in tensile strength when a tailored blank after butt welding is used to form a hot press-formed product is easily suppressed. Further, similarly, it is easy to suppress the decrease in fatigue strength. The more preferable lower limit of the plate thickness ratio is 92%, and further preferably 95%.
The thickness of the base material steel plate 12 at the first exposed portion 22 and the thickness of the base material steel plate 12 at the first plated portion 26 at the end portion of the butt welding steel plate 100 are average thicknesses. The plate thickness ratio is an average value.
Plate thickness ratio=(thickness of base material steel plate 12 at first exposed portion 22)/(thickness of base material steel plate 12 at first plated portion 26) (11)
[0072]
Here, as a method for measuring the plate thickness ratio from the tailored blank and the hot press-formed product, the following methods can be mentioned. The plate thickness ratio is measured, for example, in a tailored blank and a hot press-formed product, the first exposed portion 22 and the second plated portion 24 of the base material steel sheet 12 that is between the weld metal portion and the steel sheet 100 for butt welding. It can be measured by observing the base material steel plate 12 in.
[0073]
The thickness of the base material steel plate 12 at the first exposed portion 22 at the end of the butt welding steel plate 100 and the thickness of the base material steel plate 12 at the first plated portion 26 are obtained by cutting the butt welding steel plate 100 in the thickness direction, It can be determined by observing the cross section with an optical microscope.
Specifically, the thickness of the base material steel plate 12 at the first exposed portion 22 and the thickness of the base material steel plate 12 at the first plated portion 26 are respectively the second plating along the direction in which the first exposed portion 22 extends. The value obtained at five positions obtained by dividing the entire length of the portion 24 into five equal parts is taken as the average value.
[0074]

The second plating portion 24 is an end portion where the butt-welding steel plate 100 is scheduled to be welded, like the first exposed portion 22, and is the end where the first exposed portion 22 is provided. Formed on the part. And the 2nd plating part 24 is an edge side of the butt-welding steel plate 100 rather than the 1st exposed part 22 in at least one surface of the edge part located in the periphery of the butt-welding steel plate 100, and a butt-welding steel plate. It is preferably provided in a region including the edge 100A of 100. That is, it is preferable that the second plated portion 24 is provided along the edge 100A of the butt-welding steel plate 100 at the end portion where welding is planned.
[0075]
The second plated portion 24 formed on at least one surface of the end portion located around the butt welding steel plate 100 may be formed as follows. That is, the butt-welding steel plates 100 are welded in a state where the end faces of the butt-welding steel plates 100 having the first exposed portion 22 and the second plated portion 24 are butted. After that, the second plated portion 24 is formed so that the second plated portion 24 does not exist at the boundary between the weld metal portion formed on the tailored blank and the steel plate 100 for butt welding.
That is, the second plated portion 24 is formed in a region including the edge of the butt-welding steel plate 100 so as to be included in the weld metal portion after the butt welding. In this state, the second plated portion 24 is provided on at least one surface of the end portion of the butt-welding steel plate 100 along the edge of the butt-welding steel plate 100.
[0076]
In the first direction F1, it is preferable that (all of) the second plated portion 24 exist in a range from the edge 100A of the butt welding steel plate 100 to 0.5 mm. When the second plated portion 24 exists in this range, the second plated portion 24 is likely to be included in the weld metal portion after the butt welding. The second plated portion 24 is preferably present in the range from the edge 100A of the butt welding steel plate 100 to 0.4 mm, and is present in the range from the edge 100A of the butt welding steel plate 100 to 0.3 mm. Is more preferable.
When the butt welding is laser welding, the width of the second plated portion 24 in the first direction F1 (the distance from the edge 100A of the butt welding steel plate 100 to the first exposed portion 22 in the first direction F1. The width of the second plated portion 24) is preferably 0.1 mm to 0.25 mm. When used for plasma welding, the width of the second plated portion 24 is preferably 0.1 mm to 0.4 mm.
[0077]
Here, the width of the 1st exposed part 22 is the average value which measured the width of the 1st exposed part 22 at 5 places, and the width of the 2nd plating part 24 measured the width of the 2nd plating part 24 at 5 places. It is an average value. The measurement locations of the first exposed portion 22 and the second plated portion 24 are five positions that divide the entire length of the first exposed portion 22 into five equal parts in the direction in which the first exposed portion 22 extends.
The method of measuring the width of the first exposed portion 22 and the width of the second plated portion 24 is as follows.
A cross section in which the entire width of the first exposed portion 22 and the second plated portion 24 formed at the end of the butt welding steel plate 100 can be observed (for example, a cross section along the first direction F1 in a plan view of the butt welding steel plate 100). Five samples for measurement containing are collected. The measurement sample is taken from five positions where the length of the first exposed portion 22 formed in the direction along the edge 100A of the butt-welding steel plate 100 is divided into five equal parts. Next, cutting is performed so that the cross section of the butt-welding steel plate 100 is exposed. After that, the cut measurement sample is embedded in a resin, polished, and the cross section is enlarged with a microscope. Then, for one sample, the width of the first exposed portion 22, which is the distance from the second plated portion 24 to the first plated portion 26, is measured. Further, the distance between both edges of the second plated portion 24 is measured for each sample.
[0078]

The first plating portion 26 may have the same structure as the region other than the end portion of the butt-welding steel plate 100. For example, the thickness of the base material steel plate 12, the thickness of the intermetallic compound layer 16, and the thickness of the aluminum plating layer 14 in the first plating portion 26 may be the same as the respective thicknesses of the butt welding steel plate 100 other than the end portions. Good. However, at least a part of the thickness of the aluminum plating layer 14 in the first plating portion 26 may be larger than the thickness of the aluminum plating layer 14 at the end of the butt welding steel plate 100.
[0079]
Conventionally, a tailored blank is manufactured by butt-welding a plated steel sheet plated with a metal mainly containing aluminum by a welding method such as laser welding or plasma welding. A large amount of aluminum due to aluminum plating may be mixed into the weld metal portion of the butt welded portion of the tailored blank. When the tailored blank thus obtained was hot press-molded, the weld metal part was sometimes softened. For example, in the tailored blank after the hot press forming, as a result of a tensile strength test of a portion including a weld metal portion, an example in which breakage occurs in the weld metal portion is also reported.
[0080]
In order to avoid breakage of the weld metal portion, for example, in Patent Document 1, the aluminum plating layer of the welding planned portion to be welded is removed, and the butt-welding steel plate is continuously stretched from the edge to the region where the aluminum plating is formed. A steel plate for butt welding in which an intermetallic compound layer remains is disclosed. Further, Patent Document 1 discloses a tailored blank in which a planned welding portion of a butt-welding steel plate is butt-welded.
[0081]
Then, the aluminum plating layer is removed to obtain a butt-welding steel sheet in which the intermetallic compound layer is left, and the tail blank is manufactured by butt-welding in a state where the end faces of the region in which the intermetallic compound layer is left are abutted. In this case, the fatigue strength of the tailored blank decreases.
In the case of a butt-welding steel sheet in which an intermetallic compound layer is continuously left over from the area where the aluminum plating layer is formed to the planned welding part, between the hard and brittle metal between the weld metal part and the area where the aluminum plating layer is formed. The compound layer remains. In this case, it is affected by the intermetallic compound layer remaining at the boundary (stress concentration part) between the weld metal part and the weld heat affected part. As a result, when a tailored blank is formed from the steel plate for butt welding disclosed in Patent Document 1, and a hot press-formed product using the tailored blank is subjected to repeated loads, the fatigue strength of the joint decreases. Furthermore, in this tailored blank, since aluminum eluted from the intermetallic compound layer is contained in the portion of the weld metal portion near the edge of the region where the aluminum plating layer is formed, the weld metal portion of this portion softens. And the fatigue strength of the weld metal part decreases.
Therefore, the steel sheet for butt welding, which only removes the aluminum plating layer at the planned welding portion, has not been sufficiently applied to a portion where fatigue characteristics are important.
[0082]
Further, in Patent Document 2 to Patent Document 5, a tailored blank is obtained by butt-welding a steel plate for butt welding in which an aluminum plating layer and an intermetallic compound layer of a welded part to be welded are removed, and the welded part of the steel plate for butt welding is butt-welded. Is disclosed.
[0083]
However, with a tailored blank that was butt-welded with the intermetallic compound layer and the aluminum plating layer removed, and the end faces of the regions from which these layers were removed were butt-welded together, when applied to a hot press-formed product. , The corrosion resistance of the welded metal part after painting is reduced. When both layers of the intermetallic compound layer and the aluminum plating layer are removed from the welded portion, the amount of aluminum mixed in the welded metal portion is very small. Therefore, for example, in the butt-welding steel plates disclosed in Patent Documents 2 to 5, scale (a compound of iron) is likely to occur in the tailored blank. As a result, when a hot press-formed product formed by hot press-forming a tailored blank is applied, the adhesion of the paint on the surface of the weld metal part is reduced, and the post-coating corrosion resistance of the weld metal part is reduced.
[0084]
On the other hand, the butt-welding steel plate 100 of the present disclosure removes not only the aluminum plating layer 14 adjacent to the first plating portion 26 but also the intermetallic compound layer 16, and the base metal steel plate 12 is exposed first exposure. It has a section 22. Furthermore, the steel plate 100 for butt welding of this indication has the 2nd plating part 24 in which the intermetallic compound layer 16 and the aluminum plating layer 14 were provided.
That is, the steel plate 100 for butt welding of the present disclosure does not have the hard and brittle intermetallic compound layer 16 in the first exposed portion 22 where the base steel plate 12 is exposed. Further, in the butt-welding steel plate 100 of the present disclosure, the second plated portion 24 where the intermetallic compound layer 16 and the aluminum plating layer 14 remain is present in a region including the edge 100A of the butt-welding steel plate 100. ..
[0085]
Therefore, the tailored blank obtained by butt-welding the end faces of the butt-welding steel plate 100 having the first exposed portion 22 and the second plated portion 24 by using the butt-welding steel plate 100 of the present disclosure. Does not have the hard and brittle intermetallic compound layer 16 at the boundary between the weld metal portion and the weld heat affected zone. Aluminum of the intermetallic compound layer 16 and the aluminum plating layer 14 is not included in the portion of the weld metal portion near the edge of the first plating portion 26. Further, the second plated portion 24 is taken into the weld metal portion after butt welding (that is, the aluminum of the second plated portion 24 is mixed into the weld metal portion in an appropriate amount).
Therefore, even if this tailored blank is used as a hot press-formed product, it is considered that the decrease in the fatigue strength of the weld metal part is suppressed. Further, since the generation of scale is suppressed on the surface of the welded metal portion, the chemical conversion treatment property is improved and the adhesion of the paint is improved. Therefore, it is considered that the weld metal portion is excellent in corrosion resistance after coating even after being coated on the hot press-formed product.
Further, it is difficult for aluminum of the intermetallic compound layer 16 and 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. Therefore, it is possible to prevent the weld metal portion of this portion from softening and the fatigue strength of the weld metal portion from decreasing.
[0086]
The ratio of the width of the second plated portion 24 formed at the end portion where welding is planned is a value with respect to the total width of the second plated portion 24 and the width of the first exposed portion 22, The percentage of the width of the second plating portion 24/(the width of the second plating portion 24+the width of the first exposed portion 22) is preferably set in the range of 3% to 50%. When the width ratio of the second plated portion 24 is in this range, the fatigue strength is suppressed from being lowered, and excellent post-coating corrosion resistance is effectively obtained. On the other hand, the preferable upper limit of the width ratio of the second plated portion 24 is 40%, and the more preferable upper limit thereof is 30%.
[0087]
The width of the second plated portion 24 is preferably smaller than the width of the first exposed portion 22. According to this structure, the second plated portion 24 remains in a range less than half the distance between the edge of the butt-welding steel plate 100 and the first plated portion 26. Thereby, when the butt-welding steel plate 100 is laser-welded, it is possible to stably prevent the first weld metal part from coming into contact with the first plated part 26. Then, both the fatigue strength of the first weld metal portion and the corrosion resistance after painting can be enhanced. In an actual machine, the width of the first weld metal portion always varies, so it is preferable to configure in this way.
The second plated portion 24 is preferably formed over the entire length of the butt-welding steel plate 100. The second plated portion 24 is formed over at least the entire length of the area where welding is planned.
The first weld metal portion formed between the two butt-welding steel plates 100 is preferably separated from the edge 100B of the first plated portion 26. According to this structure, when the tailored blank is manufactured, it is possible to suppress the decrease in the fatigue strength of the first weld metal portion.
[0088]
In the butt-welding steel plate 100 of the present disclosure, the second plated portion 24 is formed in a region including the first exposed portion 22 of the base material steel plate 12 and the edge 100A of the butt-welding steel plate 100 at the end of the planned welding portion. To be done. The second plating part 24 also includes the following aspects as long as the reduction in the fatigue strength of the weld metal part is suppressed and the corrosion resistance after coating is maintained.
[0089]
For example, when punching a plated steel sheet to obtain a punched member, in an end portion located around the plated steel sheet, a region including the edge of the plated steel sheet may cause sagging due to a cutting device such as a shear. If the intermetallic compound layer and the aluminum plating layer are removed by cutting, grinding or the like on the edge of the plated steel sheet where the sagging has occurred, the intermetallic compound layer and the aluminum plating layer are removed in the portion where the sagging occurs. Layers may remain. The portion where the intermetallic compound layer and the aluminum plating layer remain is the second plating portion. At this time, it is preferable that the second plated portion includes an aluminum plated layer.
In addition, a butt-welding steel plate is manufactured by forming the second plating portion and the like on the plated steel plate.
[0090]
FIG. 4 is a cross-sectional photograph showing an example of an end portion having the first exposed portion 22 and the second plated portion 24 of the base steel sheet 12 in the butt-welding steel sheet 100 of the present disclosure.
Referring to FIG. 4, sagging occurs in a region between the edge 100A of the butt-welding steel plate 100 and the edge 100C at the boundary between the first exposed portion 22 and the second plated portion 24. A second plated portion 24, on which the aluminum plating layer 14 and the intermetallic compound layer 16 remain, is formed on the base material steel plate 12 at the portion where the sagging has occurred. On the other hand, in the region from the edge 100B of the first plated portion 26 to the edge 100C at the boundary between the first exposed portion 22 and the second plated portion 24, the first exposed portion where the base steel plate 12 is exposed. 22 is formed.
[0091]
By mixing aluminum contained in the second plated portion 24 into the weld metal portion in an appropriate amount, the corrosion resistance of the weld metal portion after coating becomes excellent. For this reason, in the butt-welding steel plate 100 of the present disclosure, when sagging occurs, the aluminum plating layer 14 and the intermetallic compound layer 16 remaining in the sagging portion are not removed, and are used as the second plating portion. use. At this time, it is preferable that the second plating portion include the aluminum plating layer 14.
[0092]
As an example of a preferable method of forming the first exposed portion 22 and the second plated portion 24 on at least a part of both surfaces of the end portion located around the plated steel sheet (steel for butt welding), for example, the following method is used. Can be mentioned.
At least a part of the end portion located around the plated steel sheet, the intermetallic compound layer 16 and the aluminum plating layer 14 formed on both surfaces of the base steel sheet 12 are removed by cutting or grinding. Thereby, the intermetallic compound layer 16 is formed on the first exposed portion 22 where the base steel plate 12 is exposed and on at least one surface of the end portion located around the plated steel sheet, on the edge side of the plated steel sheet with respect to the first exposed portion 22. And a step of forming the second plated portion 24 on which the aluminum plating layer 14 remains (formation method A).
[0093]
The forming method A is, for example, a method of forming the first exposed portion 22 and the second plated portion 24 on the end portion of the plated steel sheet as follows. First, a plated steel sheet cut into a desired size is prepared as a steel sheet before forming a tailored blank. Next, the aluminum plating layer 14 and the intermetallic compound layer 16 formed on both sides of the base material steel sheet 12 are removed by cutting or grinding at least a part of both sides of the end of the plated steel sheet after cutting. .. At this time, the 1st exposed part 22 which the base material steel plate 12 exposes is formed in the edge part of a plated steel plate. At this time, the second plated portion 24 is further formed along the edge of the plated steel sheet on the edge of the plated steel sheet with respect to the first exposed portion 22 on at least one surface of the end portion located around the plated steel sheet.
[0094]
The method of removing the first exposed portion 22 by cutting is not particularly limited. For example, the cutting may be performed by machining with a cutting tool, an end mill, a metal saw, or the like. Grinding may be performed by machining with a grindstone, a grinder, a sander, or the like. Further, these methods may be combined to remove the intermetallic compound layer 16 and the aluminum plating layer 14 to form the first exposed portion 22.
[0095]
Another method is to remove the intermetallic compound layer 16 and the aluminum plating layer 14 by laser processing such as laser gouging. Further, these methods may be combined to remove the intermetallic compound layer 16 and the aluminum plating layer 14 to form the first exposed portion 22.
When the first exposed portion 22 is formed by laser processing such as laser gouging, heat is applied to the base material steel plate 12 in the portion where the first exposed portion 22 is formed, which is caused by water vapor in the atmosphere. Then, hydrogen may be mixed in. Further, after laser processing, the base material steel plate 12 in the portion where the first exposed portion 22 is formed is rapidly cooled, so that martensite occurs in the metal structure of the base material steel sheet 12 in this portion. This may cause delayed fracture at the end surface of the butt-welding steel plate 100 before welding.
[0096]
On the other hand, when the first exposed portion 22 is formed by machining, the temperature rise of the base material steel plate 12 in the portion where the first exposed portion 22 is formed is suppressed and martensite does not occur. Moreover, since hydrogen does not enter, the occurrence of delayed fracture is suppressed. In this respect, as a method for forming the first exposed portion 22, it is preferable to employ cutting by machining (cutting). Furthermore, when the first exposed portion 22 is formed by machining, there is no need to take measures for shielding the laser light when performing laser processing such as laser gouging, which is advantageous in terms of cost and the like.
[0097]
Further, when the first exposed portion 22 and the second plated portion 24 are formed by machining, for example, an end mill (a tip blade of the end mill, a side blade of the end mill), a metal saw, or the like may be used. Among the machining processes, the first exposed portion 22 and the second plated portion 24 are preferably formed by cutting with an end mill. That is, it is preferable to have a step of forming the first exposed portion 22 and the second plated portion 24 by cutting with an end mill. Cutting by an end mill is cutting by rotary motion. Therefore, in the first exposed portion 22 formed by the end mill, the cutting surface (the exposed surface of the base material steel plate 12 in the first exposed portion 22, the cross section at the boundary between the first exposed portion 22 and the first plated portion) is fine. There are cutting marks with irregular shapes.
[0098]
A first exposed portion 22 on at least a part of both surfaces of an end portion located around the butt welding steel plate 100 (plated steel plate), and a second plated portion on at least one surface of an end portion located around the butt welding steel plate 100. If 24 is formed, the order of forming the first exposed portion 22 and the second plated portion 24 at the end is not limited to the above-mentioned forming method A.
As an example of another preferable method of forming the first exposed portion 22 on both surfaces of the end portion located around the plated steel sheet and the second plated portion 24 on at least one surface of the end portion located around the plated steel sheet, for example, The following methods are available.
[0099]
The aluminum plating layer 14 and the intermetallic compound layer 16 formed on both surfaces of the base material steel plate 12 are removed by cutting or grinding in the regions of both surfaces other than the end portions of the plated steel sheet to expose the base material steel plate 12. The two first exposed portions 22 and the second intermetallic compound layer 16 and the aluminum plating layer 14 remaining so as to be sandwiched between the two first exposed portions 22 on at least one surface other than the end portion of the plated steel sheet. And a step of forming the plated portion 24, and cutting the plated steel sheet so that the second plated portion 24 has the region including the edge of the plated steel sheet, and at least one of both surfaces of the end portion of the plated steel sheet (steel for butt welding) Part, the base material steel plate 12 is exposed, and the intermetallic compound layer 16 and the aluminum plating layer are provided on at least one surface of the end of the plated steel plate, on the edge side of the plated steel plate with respect to the first exposed part 22. And a step of forming the second plated portion 24 on which 14 remains (formation method B).
[0100]
The forming method B is, for example, specifically the following method. First, punching is performed to prepare a plated steel sheet cut into a desired size. Next, with respect to the cut plated steel sheet, the aluminum plating layer 14 and the intermetallic compound layer 16 formed on the base material steel sheet 12 were removed by cutting or grinding to expose the base material steel sheet 12 The exposed portion 22 is formed. Two first exposed portions 22 are formed in a region other than the first plated portion 26 so as to extend in one direction, for example. In the region sandwiched by the two first exposed portions 22, the second plated portion 24 where the intermetallic compound layer 16 and the aluminum plated layer 14 remain is formed. Then, in the plated steel sheet after cutting, the second plated portion 24 sandwiched between the two first exposed portions 22 is cut so that the second plated portion 24 is along the edge of the plated steel sheet. The steel plate for butt welding obtained by cutting is a steel plate before forming a tailored blank.

claims
[Claim 1]
A first plated portion in which an intermetallic compound layer and an aluminum plating layer are sequentially provided on the
surface of a base material steel plate, a first exposed portion where the base material steel plate is exposed, and the
base material steel plate On the surface of the base metal plate, from the side of the steel plate, the intermetallic compound layer, the second plating portion provided with the aluminum plating layer , and is perpendicular to the thickness direction of
the
steel plate, from the first plating portion The first plating portion, the first exposed portion, the second plating portion, the edge of the steel sheet on at least one surface of the base steel sheet in the first direction toward the one edge of the steel sheet. Are arranged in this order,
and at least the first plated portion, the first exposed portion, and the edge of the steel sheet are arranged in this order on the other surface of the base material steel sheet in the first direction. Steel plate.
[Claim 2]
The said 1st plating part, the said 1st exposed part, the said 2nd plating part, and the said edge of the said steel plate are arrange|positioned in this order on the other surface of the said base material steel plate in the said 1st direction. The steel sheet according to Item 1.
[Claim 3]
The steel plate according to claim 1 or 2, wherein in the first direction, the second plated portion is present within a range of 0.5 mm from the edge of the steel plate.
[Claim 4]
The base steel sheet is mass%,
C: 0.02% to 0.58%,
Mn: 0.20% to 3.00%,
Al: 0.005% to 0.20%,
Ti: 0% ~0.20%,
Nb:0%~0.20%,
V:0%~1.0%,
W:0%~1.0%,
Cr:0%~1.0%,
Mo:0% ~1.0%,
Cu:0%~1.0%,
Ni:0%~1.0%,
B:0%~0.0100%,
Mg:0%~0.05%,
Ca:0% ~0.05%,
REM: 0% ~ 0.05%,
Bi: 0% ~ 0.05%,
Si: 0% ~ 2.00%,
P: 0.03% or less,
S: 0.010%
hereinafter, N: 0.010% or less, and
the balance: steel sheet according to any one of claims 1 to 3 having a chemical composition consisting of Fe and impurities.
[Claim 5]
The average thickness of the aluminum plated layer in the first plated portion is 8 μm to 40 μm, and the average thickness of the intermetallic compound layer in the first plated portion is 3 μm to 10 μm. The steel sheet according to any one of items.
[Claim 6]
The second plated portion is provided only on one surface of the steel plate
, and the width cμm of the second plated portion in the first direction and the thickness fμm of the aluminum plated layer in the second plated portion are expressed by the formula (1). The steel sheet according to any one of claims 2 to 4, which satisfies the above condition.
385.48f −0.914 ≦c≦500 ••• (1)
[Claim 7]
The second plated portions are respectively provided on both sides of the steel plate
, and the width cμm of the second plated portion in the first direction and the thickness fμm of the aluminum plated layer in the second plated portion are expressed by the formula (2). The steel sheet according to any one of claims 2 to 4, which satisfies the above condition.
359.65f- 1.129 ≤c≤9368f- 0.904　...(2)
[Claim 8]
The steel plate according to any one of claims 1 to 7, wherein a width of the second plated portion is smaller than a width of the first exposed portion in the first direction.
[Claim 9]
The second plating is applied to a lower region of the surface of the base material steel plate, which is located on the inner side of the base material steel plate in the thickness direction than an imaginary surface extending the surface of the first exposed portion in the first direction. The steel plate according to any one of claims 1 to 8, wherein a part is provided.
[Claim 10]
The steel plate according to any one of claims 1 to 9, wherein the edge of the steel plate and the second plated portion are adjacent to each other in the first direction.
[Claim 11]
The 2nd exposed part which the said base material steel plate exposes is provided between the said edge of the said steel plate, and the said 2nd plating part in the said 1st direction. Steel plate.
[Claim 12]
The steel plate according to claim 11, wherein a width of the second exposed portion is smaller than a width of the first exposed portion in the first direction.
[Claim 13]
The steel plate according to claim 11 or 12, wherein a width of the second exposed portion is 0.01 mm or more and a width of the first exposed portion is 0.05 mm or more in the first direction.
[Claim 14]
In a tailored blank comprising a first weld metal part and at least two steel plate parts connected via the first weld metal
part, each of the at least two steel plate parts is
on a surface of a base material steel plate, An intermetallic compound layer, a first plating part provided with an aluminum plating layer in order from the base material steel plate side, and a
first exposed part where the base material steel plate is exposed. In each of the steel plate parts, each of the steel plates
is provided.
In a second direction which is perpendicular to the thickness direction of the portion and which extends from the first plated portion toward the first weld metal portion, on both surfaces of the base material steel sheet, the first plated portion, the first exposed portion, A tailored blank in which the first weld metal parts are arranged on the same surface in this order.
[Claim 15]
The tailored blank according to claim 14, wherein an aluminum concentration contained in the first weld metal portion is 0.05% by mass to 1% by mass.
[Claim 16]
A first intermetallic compound part in which a first intermetallic compound layer is provided on the surface of the first base material steel plate, a third exposed part in which the first base material steel plate is exposed, and an aluminum concentration contained in the first intermetallic compound part is 0. A second weld metal part having an amount of 05 mass% to 1 mass%, a fourth exposed part where the second base material steel plate is exposed, and a second intermetallic compound layer provided on the surface of the second base material steel plate. A hot press-formed product in which the second intermetallic compound portion is arranged in this order along the surface of the first base material steel plate and the surface of the second base material steel plate.
[Claim 17]
A third weld metal part, and a third steel plate formed into an open tubular shape in which two ends in the circumferential direction face each other, and the two end parts are connected to each other via the third weld metal part. In the steel pipe,
each of the two end portions of the third steel plate is a
first plated portion in which an intermetallic compound layer and an aluminum plating layer are provided on both surfaces of a base steel plate in order from the base steel plate side. ,
a first exposed portion to which the base steel sheet is exposed
with a
steel pipe in the circumferential direction, the first plating unit, the first exposed portion, the third weld metal portion, which are arranged in this order.
[Claim 18]
The steel pipe according to claim 17, wherein an aluminum concentration contained in the third weld metal portion is 0.05% by mass to 1% by mass.
[Claim 19]
A third intermetallic compound part in which a third intermetallic compound layer is provided on the surface of the third base material steel plate, a fifth exposed part in which the third base material steel plate is exposed, and an aluminum concentration contained in the third intermetallic compound part is 0. A third weld metal part having an amount of 05% by mass to 1% by mass, a sixth exposed part where the fourth base material steel plate is exposed, and a fourth intermetallic compound layer provided on the surface of the fourth base material steel plate. A hollow quenched product in which the fourth intermetallic compound portion is arranged in this order along each of both surfaces of the third base material steel plate and each of both surfaces of the fourth base material steel plate.
[Claim 20]
One of a plated steel sheet manufacturing step of manufacturing a plated steel sheet in which an intermetallic compound layer and an aluminum plated layer are sequentially provided on the surface of the base steel sheet from the side of the base steel sheet, and the
aluminum plated layer and the intermetallic compound layer. By removing the portion, the first exposed portion that exposes the base material steel plate and the intermetallic compound layer and the aluminum plating layer remain on the surface of the base material steel plate in order from the base material steel plate side. A removing step of forming a first plating part and a second plating part on which the intermetallic compound layer and the aluminum plating layer remain on the surface of the base material steel
plate; In the manufacturing method, in the
removing step, the base metal is perpendicular to a thickness direction of the plated steel sheet in a first direction from a central portion of the plated steel sheet to one edge of the plated steel sheet in a plan view. The first plated portion, the first exposed portion, the second plated portion, the edge of the plated steel sheet are arranged in this order on at least one surface of the steel sheet, and in
the first direction, the mother A method for manufacturing a steel sheet, wherein at least the first plated portion, the first exposed portion, and the edge of the plated steel sheet are arranged in this order on the other surface of the material steel sheet.
[Claim 21]
In the removing step, in the first direction, on the other surface of the base material steel sheet, the first plated portion, the first exposed portion, the second plated portion, the edge of the plated steel sheet, The method for manufacturing a steel sheet according to claim 20, wherein the steel sheets are arranged in order.
[Claim 22]
The method for manufacturing a steel sheet according to claim 20 or 21, wherein in the removing step, a step of mechanically removing the aluminum plating layer and the intermetallic compound layer is performed.
[Claim 23]
The method for manufacturing a steel sheet according to claim 22, wherein in the mechanically removing step, a removing step of removing the aluminum plating layer and the intermetallic compound layer by cutting or grinding is performed.
[Claim 24]
The method for producing a steel sheet according to claim 23, wherein in the removing step, the aluminum plating layer and the intermetallic compound layer are removed by cutting with an end mill.
[Claim 25]
In the step of mechanically removing, prior to the removing step, the plated steel sheet is cut or pressed to partially deform the plated steel sheet, and a low portion is formed on the surface of the base steel sheet of the plated steel sheet. The lower part forming step of forming a region is performed, and the
direction that is perpendicular to the thickness direction of the plated steel sheet and that goes from the central part of the plated steel sheet to one edge of the plated steel sheet in plan view is the first direction. At this time, the
lower portion region is located on the inner side of the base material steel plate in the thickness direction of the plated steel plate than the virtual surface extending the surface of the undeformed portion of the base material steel plate in the first direction. In the
removing step, the aluminum plating layer and the intermetallic compound layer existing outside the plated steel sheet in the thickness direction relative to at least the virtual surface are cut, and the region is formed on the lower region. The method for manufacturing a steel sheet according to claim 23 or 24, wherein the second plating layer is formed.
[Claim 26]
The thickness per one surface of the aluminum plating layer is a μm, the thickness per one surface of the
intermetallic compound layer is b μm, the thickness of the
plated steel sheet is t μm, and
the deepest bottom depth of the bottom region is x μm. , The
lower portion depth indicates the distance from the virtual surface to the surface of the base steel sheet in the lower portion region
, and the depth in the thickness direction of the plated steel sheet of the region cut in the deleting step is yμm. The method for manufacturing a steel sheet according to claim 25,
wherein when the distance between the first plated portion and the second plated portion is N μm,
equations (5) to (9) are satisfied.
10≦a+b<50 •••(5)
2%≦(x/t)≦15% ••(6)
a+b