Technical field
[0001]
　The present invention relates to a hot excellent hot stamping steel sheet and a manufacturing method thereof in scale adhesion during stamping, and hot stamping molded article is a molded article thereof.
Background technique
[0002]
　Viewpoint's member such door guard bar and side members of automobiles, has been considered lighter to cope with the recent fuel efficiency trends, in terms of materials, even if thinned strength and collision safety is ensured high strength of the steel sheet has been promoted from. Hereinafter, it means both the tensile strength and yield strength and strength. However, the formability of the material is so deteriorated in association with the intensity is increased, to reduce the weight of the member, it is necessary to manufacture a steel sheet that satisfies both the formability and high strength. As a method for obtaining a high strength at the same time high formability has TRIP (TRansformation Induced Plasticity) steel utilizing the martensite transformation of retained austenite which is described in Patent Documents 1 and 2, is expanding in recent years applications . However, this steel, although the deep drawability and the elongation at the time of molding is improved, because the steel sheet has high strength, has a problem of poor shape fixability of the member after press forming.
[0003]
　Meanwhile, as a method for forming a high-strength steel sheet inferior in moldability shape fixability good technique called Patent Document 3 and Patent Document 4 warm press as described in the present. This approach, the strength of the steel sheet is a technique of performing molding at a temperature of about 500 ° C. from 200 ° C. to decrease. However, when considering the molding of the above high strength steel sheet 780 MPa, even raising the molding temperature, still or in some cases the strength of the steel sheet is difficult to mold high strength of the steel sheet after molding is lowered by heating It has a problem or there is a case where a predetermined strength can not be obtained.
[0004]
　As a method for solving these problems, after cutting a soft steel plate into a predetermined size, after heating the steel sheet to austenite single phase region above 800 ° C., pressed at austenite single-phase region, as disclosed in Patent Document 5 performs a molding, there is then a technique called hot stamp to perform quenching. As a result, it has become possible to produce a superior member of the above high strength and shape fixability 980 MPa.
[0005]
　However, the hot stamp, insert the steel sheet in a heating furnace, or from heating to a high temperature exceeding 800 ° C. by electrical heating or far infrared heating in the atmosphere, a problem that the scale is generated on the surface of the steel sheet have. Since the generated scale mold is worn by desorption during hot stamp, it is required to scale adhesion at the time of hot stamping is good. As a technique for solving these problems, for example, a technique for suppressing occurrence of scale is known by the atmosphere in the heating furnace and the non-oxidizing atmosphere in Patent Document 6. However, the equipment cost must be strictly enforced controlled atmosphere in the heating furnace is increased, inferior in productivity. Also, removed steel sheet so are exposed to the atmosphere, it had a problem that it can not avoid the formation of scale. In addition, in recent years, for the purpose of improving productivity of the hot stamping, a technique for electrically heating the steel sheet in the atmosphere it is being developed. During the air heating, it is difficult to avoid oxidation of the steel sheet is likely problems mold wear of scale detachment during hot stamp actualized. As a result, it is essential repair of regular mold.
[0006]
　As the steel plate to solve these problems, a technique for suppressing wear of the mold is known by the scale of the separation by using a steel plate galvanized or Al plated surface of the steel sheet to hot stamping. However, since the plating of zinc plating or Al at the time of heating becomes to melt the liquid phase, zinc or Al had the problem of adhering to the heating furnace and the mold during transport or during pressing of a steel sheet. Deposit of the deposited zinc or Al is cause indentation flaws of the hot stamping material, has a problem that exacerbates the appearance attached to the molded body. Therefore, it was necessary to repair the regular die.
[0007]
　Therefore, without the scale peeled off when hot stamping, and adhesion of molten metal to the mold is the development of hot stamping steel plate which does not cause it has been desired.
CITATION
Patent Literature
[0008]
Patent Document 1: JP-A-1-230715 JP
Patent Document 2: JP-A 2-217425 Patent Publication
Patent Document 3: JP 2002-143935 Patent Publication
Patent Document 4: JP 2003-154413 Patent Publication
Patent Document 5: JP 2002-18531 JP
Patent Document 6: JP 2004-106034 Patent Publication
Patent Document 7: JP 2002-18531 JP
Patent Document 8: JP 2008-240046 JP
Patent Document 9: JP 2010-174302 JP
Patent Document 10: JP 2008-214650 JP
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　The present invention has been made in view of the problems described above, excellent in scale adhesion during hot stamping, and hot stamping steel plate adhesion does not occur in the molten metal into the mold, to provide a method of manufacturing the same, and the hot stamping member With the goal.
Means for Solving the Problems
[0010]
　The present inventors have intensively studied a technique for solving the above problems. As a result, with the intention of improving the scale adhesion of the steel sheet, the Si causes contained 0.50 wt% to 3.00 wt% in the steel sheet, the amount of anti-rust oil, which is applied to the steel plate 50 mg / m 2 ~ 1500 mg / m 2 in the range of the surface roughness of the steel sheet and Rz> 2.5 [mu] m. Also, preferably the S content in the rust preventive oil and 5 wt% or less. Thus, it was found that the scale adhesion during heating and during hot stamping improves. Generally degrade the scale adhesion by inclusion in the coating oil is concentrated to the interface between the base steel and scale. However, a limiting this content amount, by using both the anchoring effect utilizing the uneven surface of the steel sheet, and found that it is possible to secure the scale adhesion.
[0011]
　The present invention has been made based on the above findings, its gist the following.
(1) in
　mass%,
　C: 0.100% ~ 0.600%,
　Si: 0.50% ~ 3.00%, Mn:
　1.20% ~ 4.00%, Ti: 0.005% ~
　% 0.100, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~ 1.000%,
　N : 0.0100% or
　less, Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00 Pasento,
　Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～ 2.00
　Pasento, Nb: 0
　~ 0.100%%, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% to 0.0300%
　contain a composition the balance being Fe and impurities, the Rz> 2.5 [mu] m surface roughness of the steel sheet, the surface Unction amount 50 mg / m 2 ~ 1500 mg / m 2 for a steel sheet a hot stamp coating oil is characterized in that it is coated.
[0012]
(2) hot stamping steel sheet according to (1), wherein the S content in the coating oil to be oiled in the steel sheet is not more than 5% in mass%.
[0013]
(3) the composition of the steel sheet contains, by
　mass%, Ni:
　0.01% ~
　2.00%, Cu: 0.01% ~ 2.00%, Cr: 0.01% ~
　2.00%, Mo :
　0.01 Pasento ～ 2.00 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100%,
consisting of hot stamping steel sheet according to (1) or (2), characterized in that it contains one or more kinds selected from the group.
[0014]
(4) the composition of the steel sheet contains, by
　mass%, and wherein REM, Ca, in that it contains 0.0003% - 0.0300% in total of one or two or more selected from the group consisting of Ce and Mg hot stamping steel sheet according to any one of the above (1) to (3) to be.
[0015]
(5) by
　mass%,
　C: 0.100% ~ 0.600%,
　Si: 0.50% ~ 3.00%, Mn:
　1.20% ~ 4.00%, Ti: 0.005% ~
　% 0.100, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~
　1.000%, N : 0.0100% or less,
　Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00 Pasento,
　Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～ 2.00
　Pasento, Nb: 0
　~ 0.100%%, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% to 0.0300%
　containing, by casting a slab balance being Fe and impurities, directly or once hot pressure heated after cooling Performs extension, obtaining a hot-rolled steel sheet,
　the hot-rolled steel sheet, the temperature is 80 ° C. or more but less than 100 ° C., the concentration of acid in the inhibitor-containing 3 mass% to 20 mass% of 30 seconds or more acids in an aqueous solution a step of carrying out the washing,
　a step of applying the rust preventive oil to the steel sheet after carrying out the pickling
　has,
　a rust-preventive oil residual amount of the steel sheet surface 50 mg / m 2 ~ 1500 mg / m 2Method for producing a hot stamping steel plate, characterized in that to limit the.
[0016]
(6) The pickling method of manufacturing a hot stamping steel sheet according to (5), characterized in that applying the rust preventive oil to the hot-rolled steel sheet.
[0017]
(7) The pickling was carried out cold rolling the hot-rolled steel sheet further comprising the step of obtaining a cold rolled steel sheet,
　above, characterized in that for applying the rust preventive oil to the cold-rolled steel sheet (5) manufacturing method of hot stamping for steel sheet according to.
[0018]
(8) The cold-rolling was performed in pickled hot-rolled steel sheet, further comprising the step of obtaining a cold-rolled steel sheet further subjected to heat treatment in a continuous annealing facility or a box-type annealing furnace,
　the said cold-rolled steel sheet method for producing a hot stamping steel sheet according to the above (5), characterized in applying the rust preventive oil.
[0019]
(9) anti-rust oil applied to the steel sheet, the production of hot stamping steel sheet according to any one of the above (5) to (8), characterized in that the S content is not more than 5% in mass% Method.
[0020]
(10) the composition of the slab, in
　mass%, Ni:
　0.01% ~
　2.00%, Cu: 0.01% ~ 2.00%, Cr: 0.01% ~
　2.00%, Mo :
　0.01 Pasento ～ 2.00 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100%,
consisting of one or manufacturing method of hot stamping steel sheet according to any one of the above which is characterized by containing two or more (5) to (9) is selected from the group.
[0021]
(11) the composition of the slab, in
　mass%, and wherein REM, Ca, in that it contains 0.0003% - 0.0300% in total of one or two or more selected from the group consisting of Ce and Mg manufacturing method of the above (5) hot stamping steel sheet according to any one of the - (10) to be.
[0022]
(12) in
　mass%,
　C: 0.100% ~ 0.600%,
　Si: 0.50% ~ 3.00%, Mn:
　1.20% ~ 4.00%, Ti: 0.005% ~
　% 0.100, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~
　1.000%, N : 0.0100% or less,
　Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00 Pasento,
　Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～ 2.00
　Pasento, Nb: 0
　~ 0.100%%, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% to 0.0300%
　contain, it comprises the balance consisting of Fe and impurities, the interface between the scale and the base steel, depth 0.2 [mu] m ~ Range and becomes uneven 100μm Atari of .0Myuemu, there three or more, hot stamping molded tensile strength, characterized in that at least 1180 MPa.
[0023]
(13) on the surface of the hot stamping material, Si oxide, FeO, Fe 3 O 4 , and Fe 2 O 3 has, above (12), wherein the thickness of the scale is 10μm or less hot stamping body according to.
[0024]
(14) the composition of the hot stamping material, in
　mass%, Ni:
　0.01% ~ 2.00%,
　Cu: 0.01% ~ 2.00%, Cr: 0.01% ~ 2.00
　Pasento,
　Mo: 0.01 Pasento ～ 2.00 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100% ,
hot stamping molded product according to above, characterized in that it contains one or more selected from the group consisting of (12) or (13).
[0025]
(15) the composition of the hot stamping molded article, in
　mass%, REM, Ca, which contains 0.0003% - 0.0300% in total of one or two or more selected from the group consisting of Ce and Mg hot stamping molded article according to any one of the above (12) to (14), characterized in.
Effect of the invention
[0026]
　According to the present invention, excellent scale adhesion during hot stamping, and hot stamping steel plate adhesion does not occur in the molten metal to the mold, it is possible to provide a method of manufacturing the same, and the hot stamping molded article.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027]
[1] Figure 1 is a diagram showing the relationship between the surface roughness Rz of the coating oil amount and the steel plate of the steel plate.
FIG. 2 is a diagram for explaining that the S concentration of the coating oil increases the scale is liable to peel.
FIG. 3 is a diagram showing the relationship between the surface roughness Rz of the pickling time and the steel sheet.
[Figure 4A] Figure 4A is a photograph showing the surface microstructure of the hot rolled steel sheet before pickling.
[Figure 4B] Figure 4B is a photograph showing the surface microstructure of pickled.
FIG. 5 is a diagram showing the relationship between the coating amount of oil and scale thickness.
[Figure 6A] Figure 6A is a photograph showing a cross-section of the hot stamping surface of the present invention embodiment.
[Figure 6B] Figure 6B is a photograph showing a cross-section of the hot stamping surface of the comparative example.
FIG. 7 is a surface roughness Rz before the hot stamping heat treatment is less than 2.5, the number density of the bumps after the hot stamping heat treatment is a diagram for explaining that a less than 3 .
DESCRIPTION OF THE INVENTION
[0028]
　Hot stamping steel sheet of the present invention, the Si in the steel sheet causes contained 0.5% by weight to 3.0% by mass%, the amount of anti-rust oil, which is applied to the steel plate 50 mg / m 2 - 1500 mg / m 2 and in the range, the surface roughness of the steel sheet, characterized in that the Rz> 2.5 [mu] m. And, preferably the S content in the rust preventive oil and 5 wt% or less.
　First, an explanation as to why the present inventors have focused on oiled.
[0029]
　The present inventors have found that a steel sheet not subjected to plating (cold-rolled steel sheet or hot-rolled steel sheet) in order to improve the scale adhesion, have investigated the influence of the surface properties and various processes of the steel sheet. As a result, while indicating excellent scale adhesion if the steel sheet after degreasing was found that the scale adhesion when applied to rust-preventive oil is greatly deteriorated. More specifically, was investigated the relationship between the scale adhesion and rust-preventive oil, scale was found that there is a tendency to peel the S amount contained as an impurity in the rust preventive oil is increased. Detailed reason S of anti-rust oil of unknown things can be considered to have affected the scale adhesion.
[0030]
　On the one hand, pickled hot-rolled steel sheet for hot stamping was a cold-rolled steel sheet for hot stamping after cold rolling or annealing, in order to prevent the rust occurs until use from manufacture, such as mineral oil it is necessary to apply the anti-rust oil. In particular, the steel sheet after pickling is assumed that the time to use the delivery to the customer is a long time, 1500 mg / m 2 it has been common to the oiling exceeding. The present inventors have investigated the influence of oiled amount for the purpose of compatibility between the scale adhesion and rust resistance, as shown in FIG. 1, the range of the surface roughness of the coated oil amount and the steel sheet strict scale adherence was found that improved by controlling the. Unction amount 50 mg / m 2 ~ 1500 mg / m 2 effect is exerted by the. The lower limit of 50 mg / m 2 to that A, 50 mg / m since this unction amount less than it is difficult to secure a good corrosion resistance 2 was used as a coating quantity of oil lower. Preferably, 100 mg / m 2 or more, more preferably, 200 mg / m 2 is at least. The upper limit of the coating amount of oil 1500 mg / m 2 to that as is to obtain the effect of excellent scale adhesion. Oiling weight 1500 mg / m 2 1500 mg / m and the upper limit from the scale adhesion is deteriorated more than 2 is. Preferably, the upper limit is 1000 mg / m 2 is more preferably an upper limit of 900 mg / m 2, And still more preferably the upper limit is 800 mg / m 2 is. Also, oiling of the steel sheet surface since the burning at the time of heating, to cause the generation of soot. This also unction amount is preferably small.
[0031]
　Scale adhesion shown in FIG. 1 was evaluated by hot shallow drawing test in a cylindrical mold of φ70mm depth 20 mm. The steel plate at resistance heating apparatus, at 50 ° C. / s, heated to a temperature range of 800 ° C.-1100 ° C., after holding for 0 seconds to 120 seconds, the energization is stopped, 650 ° C. at cool until then cooled, subjected to hot shallow drawing at the die. The test specimens after molding were visually observed, scale good scale adhesion what is 5% or less exfoliated area (○), poor what area the scale is peeled off of 5 ~ 15% (△), the scale There peeled area was bad ones than 15% (×). Scale was peeled area within the scope of the present invention the most 5%.
[0032]
　Heating method without particular limitation, the evaluation of the scale adhesion is possible. For example, a heating furnace, far infrared, near infrared, and may be in any condition of electric heating. In the case of heating the steel sheet in a heating furnace to control the atmosphere in the heating furnace to suppress the oxidation of the steel sheet by thinning the scale, it is possible to obtain an excellent scale adhesion further.
[0033]
　Incidentally, the shallow drawing test temperature, the steel sheet may be any temperature range as long processed but, in general, the steel sheet for hot stamping by the process and subsequent die quenching in the austenite region, and excellent high strength and a shape freezing property. Therefore, characterization was conducted by hot shallow drawing at 650 ° C. as the Ar3 greater.
[0034]
　Oiling method as electrostatic coating oil, spray, although a roll coater or the like is generally used, not oiling method is limited as long ensured unction amount.
[0035]
　Oil type is not specified, if for example a mineral oil-based, NOX-RUST530F but (Parker Kosan Co., Ltd.) and the like are generally used unction amount as long as satisfying the scope of the present invention, the oil species is not limited.
[0036]
　May be unction amount measured by any method as long measurements, the present inventors have measured by the following method. First, a steel sheet rust-preventive oil was applied was cut into 150mm square, then the area of ​​100 mm × 100 mm were stuck to the tape so as to expose. The advance measuring the weight of the steel sheet embodying the coating oil and the seal (including the weight of the tape). Then, degreased by wiping the rust preventive oil of the steel sheet surface with a cloth moistened with acetone, the weight of the defatted steel sheet were measured, oiling amount per unit area by comparing the weight before and after degreasing It was calculated. Performed each steel three were the average of the adhesion amount of the coating oil coating weight of each of the steel sheet.
[0037]
　It is preferred to limit the S content in the rust preventive oil to 5% by weight or less. The present inventors, as shown in FIG. 2, was investigated the relationship between the S content of the coating oil and scale peeling area ratio, the more the S content of the coating in the oil is reduced to improve the scale adhesion , especially S content in oiled not more than 5 wt%, it was found that the scale peeling area is substantially 0%. Although the detailed mechanism is not known, when heated, although oil contained in the rust preventive oil is not burned, degrade the scale adhesion by S contained as an impurity remaining on the surface of the steel sheet thickening in scale It is believed to be. Therefore, S content in the rust preventive oil is preferably reduced. Preferably, it is 4 mass% or less, still more preferably 3 mass% or less. Analysis of S rust oil is not permissible in any way as long analysis, the inventors have, a rust-preventive oil applied to the steel sheet 5mL taken, X-ray fluorescence (fluorescence C line sulfur analyzer SLFA -2800 / HORIBA) analysis was performed at. For the measurement, performed in n = 3, it is defined as S content with the average value.
[0038]
　Next, description with respect to the surface roughness of the steel sheet. To ensure the scale adhesion, the surface roughness of the steel sheet is required to be Rz> 2.5 [mu] m. Results obtained by investigating the relationship between the surface roughness Rz and scale adhesion of the steel sheet are as shown in FIG. 1 described above. By providing irregularities on the interface between the scale and the base steel produced during hot stamping heat treatment, irregularities are formed on the interface between the base steel and the scale, resulting in further improvement in adhesion. This effect is generally referred to as anchoring effect. In particular, the scale generated during heating in the steel sheet thin. As a result, thin book steel thickness of the scale is the scale having an uneven under the influence of base iron surface state is formed. This is required to be Rz> 2.5 [mu] m of the surface roughness of the hot stamp preceding steel sheet. In Rz ≦ 2.5 [mu] m, low surface roughness of the steel sheet, since the anchor effect is insufficient and can not ensure good scale adhesion during hot stamping. The upper limit can be obtained an excellent scale adhesion effect of the present invention without particularly providing, excessively too improve the scale adhesion, for example, difficult to remove the scales at step after the shot blasting to become. Therefore, it is preferable that the Rz <8.0 .mu.m. More preferably, it is Rz <7.0μm. However, even if the Rz ≧ 8.0 .mu.m can be ensured excellent scale adhesion is the effect of the present invention. In the steel sheet of the Si content is less than 0.50 wt%, even as a surface roughness of Rz> 2.5 [mu] m, since the thick Fe-based scale when heated is formed, even if there is unevenness on the surface of the steel sheet excessive oxidation, the interface between the base steel and the scale becomes flat. As a result, there is no unevenness of the interface between the scale and the base steel, the effect of an effect excellent scale adhesion of the present invention is not exhibited.
[0039]
　Measurement of the surface roughness Rz is may be in any way, the present inventors have found that the tip angle of the stylus is 60 °, the tip R is 2μm contact type surface roughness meter (SURFCOM2000DX / SD3 Tokyo Seimitsu Co., Ltd. ) at a region of length 10mm measured at n = 3, and the average value and the surface roughness Rz of the individual steel sheet.
[0040]
　It will be described next scale features of hot stamping molding. Hot stamping steel sheet of the present invention is to ensure the scale adhesion by unevenness control of the interface between the scale and the base steel. Therefore, scale, Si oxide, Fe 3 O 4 , Fe 2 O 3 , and FeO may be a scale mainly composed of. Si oxides, iron metal and iron scale (FeO, Fe 2 O 3 , Fe 2 O 3 by the presence at the interface between), controlling the thickness of the iron-based scale. The scale since it needs to include a Si oxide. Since the thickness control of an iron-based oxide is the main objective, Si oxide may be present with a very thin, for example, be a 1nm to exert its effect.
[0041]
　Composition analysis of the scale of the molded body, cut out a plate from the bottom of the cylindrical portion of the shallow drawing test pieces were performed by X-ray diffraction. From the peak intensity ratio of the oxides was measured volume ratios of the Fe-based oxides. Si oxide is present very thin, since it volume ratio was less than 1%, quantitative evaluation of X-ray diffraction has been difficult. However, at a linear analysis of EPMA (Electron Probe Micro Analyzer), it is possible to verify that the Si oxides at the interface between the scale and the base steel is present.
[0042]
　Scale thickness is preferably 10μm or less. If the scale of the thickness of the 10μm or less, scale adhesion is further improved. Thermal stress scale thickness acting upon cooling during hot stamping exceeds 10μm tends to scale easily peeled due. On the one hand, then, in the scale removal process such as shot blasting or wet blasting, cracks occur between Fe-based scale, scale existing outside is peeled off. As a result, there is a problem called inferior in descaling property. Therefore, it is preferable that the scale thickness is 10μm or less. More preferably 7μm or less, more preferably 5μm or less. Scale thickness, simultaneously with controlling the Si content of the steel sheet within a predetermined range, is achieved by controlling the coating amount of oil in a predetermined range. Figure 5 shows the relationship between the coating amount of oil and scale thickness.
[0043]
　The interface between the base steel and the scale in the hot stamping molding of the present invention, there irregularities of 0.2 [mu] m ~ 8.0 .mu.m 3 or more 100μm Atari. The Figure 6A shows the interfaces photograph of the base steel and the scale of the molded product excellent in scale adhesion, FIG 6B, shows the interface photograph of the base steel and the scale inferior to the scale adhesion. This unevenness, from contributing to the scale to improve adhesion during hot stamping can ensure excellent scale adhesion by controlling the above range. Anchor effect is not sufficient for irregularities of less than 0.2 [mu] m, less scale adhesion. In the above irregularities 8.0 .mu.m, scale adhesion is excessively strong, in the subsequent descaling step, for example, the interface of the unevenness from the hard descaling by shot blasting or wet blasting, the scale and the base steel 8 it is preferable that the .0μm below. More preferably, not more than 6.0 .mu.m, more preferably less 4.0 .mu.m. However, even irregularities exceeds 8.0 .mu.m, excellent scale adhesion is the effect of the present invention can ensure.
[0044]
　The number per 100μm of unevenness of 0.2 [mu] m ~ 8.0 .mu.m is less than 3, since the improvement of the scale adhesion is not sufficient, and three or more. On the other hand, excellent scale adhesion is the effect of the present invention without defining the upper limit of the number is particularly can be ensured. Incidentally, unevenness of the molded body is correlated with the surface roughness Rz of the steel sheet as shown in FIG. 7, it can be controlled by the surface roughness Rz> 2.5 [mu] m of the steel sheet.
[0045]
　Next, a description will be given chemical composition of the steel sheet and hot stamping molding of the present invention. Hereinafter,% means mass%.
　C: 0.100% ~ 0.600%
　C is an element contained in order to increase the strength of the steel sheet. When C content is less than 0.100%, it is impossible to ensure a tensile strength of at least 1180 MPa, it can not ensure a high strength molded article which is the object of the hot stamp. On the other hand, C content exceeds 0.600%, the weldability and workability becomes insufficient, C content is 0.100% - 0.600%. Preferably 0.100% 0.550%, more preferably 0.150% 0.500%. However, if you do not need the strength of the molded body, scale adhesion to the C content is better even than 0.150% can ensure.
[0046]
　Si: 0.50% ~
　3.00% Si is an essential element since it improves the scale adhesion by controlling the scale composition during hot stamping. When Si content is under less than 0.50% can not control the thickness of the Fe-based scale, it can not ensure good scale adhesion. Therefore, Si content should be 0.50% or more. Also, considering that the molded during hot stamping is applied to the tight member, it is preferred to increase the Si content. Thus, preferably at Si content 0.70% or more, more preferably 0.90% or more. Meanwhile, Si increases the Ae3 point, the martensite to increase the heating temperature required for the main phase, the productivity and economy contained excessively lowered. Therefore, Si content is a maximum of 3.00%. Preferably the upper limit of the Si content is 2.5%, more preferably from 2.0% limit. However, securing the scale adhesion excellent except for productivity and economic efficiency are possible.
[0047]
　Mn: 1.20% ~
　4.00% containing Mn delays the ferrite transformation in the cooling process during hot stamping, to a hot stamping molded article and martensite main phase structure, or 1.20% there is a need to be. The Mn content is less than 1.20%, it is impossible to martensite as a main phase, so ensuring high strength which is the object of the hot stamping body is difficult, 1.20% of the lower limit of the Mn content to. However, if you do not need the strength of the molded body, scale adhesion to the Mn content is excellent even less than 1.20% can ensure. On the other hand, the Mn content is effect is saturated if it exceeds 4.00% causes embrittlement, casting, cold rolling, or to cause cracking during hot rolling, the upper limit of the Mn content is 4 and .00%. Preferably in the range Mn content is 1.50% ~ 3.50%, more preferably from 2.00% to 3.00%.
[0048]
　Ti: 0.005% ~
　0.100% Ti combines with N, by forming the TiN, and suppress the B is a nitride, an element improving the hardenability. This effect, since the Ti content is significant at 0.005% or more, the Ti content is 0.005% or more. However, if the Ti content exceeds 0.100%, Ti carbides are formed, reducing contributes C amount to strengthen martensite, since the decrease in strength is caused, the upper limit of the Ti content is 0.100 % to. Preferably in the range C content is 0.005% 0.080%, more preferably in the range of 0.005% to 0.060%.
[0049]
　B: 0.0005% ~ 0.0100%
　B increases the hardenability during hot stamping, contribute to the main phase and martensite. This effect, since the B content is remarkable in 0.0005% or more, B content should be 0.0005% or more. On the other hand, when the B content exceeds 0.0100%, the effect thereof is saturated, borides iron is precipitated, to lose hardenability effect of B, the upper limit of B content is 0.0100 % to. Preferably in the range B content is 0.0005% - 0.0080%, more preferably from 0.0005% to 0.0050%.
[0050]
　P: 0.100% or less
　P is an element that segregates at mid-thickness portion of the steel sheet, is also an element embrittle the weld. Therefore, 0.100% of the upper limit of the P content. More preferable upper limit is 0.050%. P content is preferably low, the lower limit the effect of the present invention is exhibited without being specifically defined, reducing the P less than 0.001%, from the viewpoint of productivity and cost of de P, economy since it is disadvantageous, it is preferable that the lower limit of 0.001%.
[0051]
　S: 0.0001% ~ 0.0100%
　S largely affects the scale adhesion, it is necessary to limit the content in the steel sheet. Therefore, 0.0100% of the upper limit of the S content. On the other hand, from the viewpoint of productivity and cost of de P, since it is economically disadvantageous, and 0.0001% the lower limit of the S content. Preferably in the range S content is 0.0001% 0.0070%, more preferably from 0.0003% to 0.0050%.
[0052]
　Al: 0.005% ~
　1.000% Al, so acts as a deoxidizer, Al content is 0.005% or more. Al content can not be obtained a sufficient deoxidizing effect is less than 0.005%, and a large amount of inclusions in the steel sheet (oxide) is present. These inclusions become starting points of fracture at the time of hot stamping is not preferable since it causes fracture. This effect, since Al content is remarkable when the 0.005% or more, Al content must be 0.005% or more. On the other hand, when the Al content exceeds 1.000% increases the heating temperature during hot stamping increasing Ac3 point. That is, hot stamping, the steel sheet was heated to austenite single phase region, and the mold pressing at hot excellent steel sheet in formability, by implementing the quenching using a mold, a high having a complicated shape it is a technique to obtain a molded product of the strength. As a result, Al is improved significantly Ac3 point when contained in a large amount, causes an increase of the heating temperature required for austenite single phase region heating, productivity is reduced. Therefore, the upper limit of the Al content should be 1.000%. Preferably in the range Al content of 0.005% to 0.500%, more preferably from 0.005% to 0.300%.
[0053]
　N: 0.0100% or less
　N forms a coarse nitride is an element degrading the bendability and hole expandability. When N content exceeds 0.0100%, the resistance expandability bendability and hole deteriorates remarkably, the upper limit of the N content is 0.0100%. Incidentally, N is the, since the cause of blowholes during welding, the smaller is preferred. Thus, preferably at the N content is 0.0070 or less, more preferably 0.0050% or less. On the other hand, the lower limit of the N content need not specifically defined, the reducing N content to less than 0.0001%, the manufacturing cost is greatly increased, 0.0001% is substantially the lower. From the viewpoint of the production cost, N content is more preferably 0.0005% or more.
[0054]
　Incidentally, the other inevitable elements may contain trace amounts. For example O forms an oxide, present as inclusions.
　In the steel plate of the present invention, furthermore, if desired, contain the following elements.
[0055]

　Ni:　
　0.01 Pasento ～ 2.00 Pasento Cu: 0.01
　Pasento ～ 2.00 Pasento Cr: 0.01 Pasento ～ 2.00 Pasento Mo: 0.01
　Pasento ～ 2.00 Pasento Ni, Cu, Cr, and Mo increases the hardenability during hot stamping, an element which contributes to high strength by the main phase and martensite. This effect, Ni, Cu, Cr, and one or more selected from the group consisting of Mo, respectively, from becoming noticeable by containing 0.01% or more, the content of these elements each is preferably 0.01%. The content of each element exceeds a predetermined amount, weldability, or hot workability, etc. is deteriorated, or because they can lead to manufacturing problems will the strength of the hot stamping steel plate is too high, these the upper limit of the content of elements preferably set to 2.00%.
[0056]
　Nb:
　0.005 ～ 0.100
　Pasento V: 0.005 ～ 0.100 Pasento W: 0.005 ～ 0.100
　Pasento Nb, V, and W, fine by suppressing the growth of austenite at the time of hot stamp grain strengthening, an element which contributes to the increase in strength and toughness increase. Therefore, it may also contain one or more selected from the group consisting of these elements. This effect, since it becomes remarkable by each element contains more than 0.005%, it is preferable that these elements contains more than 0.005%. Incidentally, when these elements are contained 0.100% greater, respectively, Nb, V, and W carbides are formed, reducing contributes C amount to strengthen martensite, since the decrease in strength is caused unfavorable. Preferably, in the range of 0.005% to 0.090%, respectively.
[0057]
　REM, Ca, Ce, and one or more of the total selected from the group consisting of Mg: 0.0003% ~ 0.0300%
　In the present invention, furthermore, REM, Ca, Ce, and from the group consisting of Mg one or more selected may contain 0.0003% - 0.0300% in total.
　REM, Ca, Ce, and Mg, together with improving the strength, which is an element contributing to the improvement of the material. REM, Ca, Ce, and when one or more of the total selected from the group consisting of Mg is less than 0.0003%, no sufficient effect is obtained, and 0.0003% the lower limit of the total it is preferable to. On the other hand, REM, Ca, Ce, and one or the two or more in total is more than 0.0300% selected from the group consisting of Mg, there is a possibility to degrade the workability in castability and hot it is preferable to 0.0300% the upper limit of the total. It is to be noted that the REM, is an abbreviation of Rare Earth Metal, it refers to the elements belonging to the lanthanide series. In the present invention, REM is often added in misch metal, also, in addition to Ce, which may contain elements of the lanthanide series in the composite.
[0058]
　In the present invention, as an inevitable impurity, La, also contain elements lanthanoid series other than Ce, to the effect of the present invention is expressed, also contain elements such as other metals as impurities, the present invention effect is the expression of.
[0059]
　Will now be described, wherein the microstructure of the hot stamping steel sheet and hot stamping molding of the present invention.
　Chemical composition, surface roughness of the steel sheet, and, if the coating amount of oil satisfies the scope of the present invention, pickled hot-rolled steel sheet, a hot-rolled steel sheet cold-rolled cold-rolled steel sheet, or after cold rolling effects of the present invention either a cold-rolled steel sheets was carried out annealing can be exerted.
[0060]
　These steel sheets, since it is heated to the austenite region of 800 ° C. than at hot stamping, the performance as a steel sheet for hot stamping that has excellent scale adhesion is the effect of the present invention without limiting microstructure especially the It is exhibited. However, prior to hot stamping, when carrying out the punching between mechanical cutting and cold steel sheets, molds, blades of the cutting machine, or to reduce the wear of the punching dies, strength of the steel sheet is better as low as possible It is preferred. Therefore, the microstructure of the hot stamping steel sheet, ferrite and pearlite, or, it is preferable that the tissue tempered bainite structure and martensite. However, as long as no mechanical cutting and wear of the punch and die during cold stamping in question, residual austenite, even contained martensite in tempering, and one or more of bainite excellent scale adhesion is the effect of the present invention can be ensured. Further, in order to reduce the strength of the steel sheet, it may be carried out heat treatment in a box annealing furnace or a continuous annealing equipment. Alternatively, after these softening treatment, performed cold rolling, also excellent scale adhesion is the effect of the present invention is secured as was controlled to a predetermined thickness.
[0061]
　Increase the strength of the shaped body after the hot stamping, the case of obtaining a high member strength, microstructure of the molded article, it is preferable that the martensite as a main phase. In particular, in order to secure the tensile strength above 1180MPa, it is preferable that the volume fraction of martensite is the main phase and 60%. Martensite, conducted a tempering after the hot stamping, it may be used as the martensite tempering. As tissue other than martensite, bainite, ferrite, pearlite, it may comprise cementite, and residual austenite. Further, even in the martensite volume fraction is less than 60%, excellent scale adhesion of the present invention can be ensured.
[0062]
　Identification of the microstructure constituting the steel sheet structure (tempered martensite, martensite, bainite, ferrite, pearlite, retained austenite and the remaining structure), confirmation of the location and measurement of the area ratio, the following method is used. For example, a reagent disclosed in Japanese Patent nital reagent and JP 59-219473, corrode steel rolling direction cross-section or rolling direction perpendicular section 1000 to 100,000 times the scanning electron microscope (SEM: Scanning Electron Microscope) and transmission electron microscopy: it is possible to observe the tissue (TEM transmission electron microscope). The present inventors, a sample was taken as an observation plane parallel plate thickness cross section in the rolling direction of the steel sheet, grinding the observation surface, and nital etching, 1/8-centered 1/4 of plate thickness 3/8 thickness range field emission scanning electron microscope: observed with (FE-SEM field emission scanning electron microscope) the area fraction was measured, and the volume fraction have it. The volume fraction of retained austenite, and parallel to the plate surface of the base material steel plate subjected to X-ray diffraction as observed surface 1/4 thickness surface was measured volume fraction.
[0063]
　Next, a method for manufacturing the hot stamping steel sheet of the present invention.
　Other operating conditions, depending on the conventional method, the following conditions are preferred on productivity.
[0064]
　In order to manufacture the steel sheet of the present invention, first, casting a slab having the same component composition as the component composition of the above-described steel sheet. As a slab subjected to hot rolling, and continuously cast slab, it is possible to use those prepared in such a thin slab caster. In the manufacturing method of the steel sheet of the present invention, after casting, immediately continuous casting performing hot rolling - compatible with processes such as direct rolling (CC-DR).
Slab heating temperature: 1100 ° C. or more
, hot rolling completion temperature: Ar @ 3 transformation point or higher
, Winding Temperature: 700 ° C. or less
, cold-rolling reduction: 30-70%
[0065]
　Slab heating temperature is preferably above 1100 ° C.. Slab heating temperature in the temperature range below 1100 ° C., since it leads to a decrease in finish rolling temperature, the strength of the finish rolling is also high tends. As a result, rolling may become difficult, because of the possibility of or cause the shape of the steel sheet after rolling defects, the slab heating temperature is preferably 1100 ° C. or higher.
[0066]
　Finish rolling temperature is preferably not less than Ar3 transformation point. Finish rolling temperature becomes higher as the rolling load below the Ar3 transformation point, rolling or becomes difficult, because of the possibility of or cause the shape of the steel sheet after rolling defects, the lower limit of the finish rolling temperature, Ar3 transformation it is preferable to a point. The upper limit of the finish rolling temperature is not necessary to determine in particular, when excessively increasing the finish rolling temperature, in order to ensure that temperature, since they must be excessively high slab heating temperatures, the upper limit of the finish rolling temperature is 1100 ℃ is preferable.
[0067]
　Coiling temperature is preferably set to 700 ° C. or less. If the coiling temperature exceeds 700 ° C., the thickness of the oxide that forms on the surface of the steel sheet excessively increased, since the deterioration of the pickling objectionable. Thereafter, when performing cold rolling is preferably set to 400 ° C. The lower limit of the coiling temperature. When the coiling temperature is below 400 ° C., extremely strength hot rolled steel sheet is increased, because it is easy to induce strip breakage and defective shape at the time of cold rolling, the lower limit of the coiling temperature be 400 ° C. It is preferred. However, if the attempt to softening by heating the wound hot rolled steel sheet in a box type annealing furnace or a continuous annealing equipment, may be wound up at a low temperature of lower than 400 ° C.. Incidentally, the rough rolled plates are joined may be subjected to a continuous finish rolling during hot rolling. Further, it may be once wound rough rolling plate.
[0068]
　Then, the hot-rolled steel sheet manufactured in this way, the temperature is 80 ° C. or more but less than 100 ° C., a pickling for 30 seconds or more the concentration of the acid in the inhibitor containing the with an aqueous solution of 3 wt% to 20 wt% performed. In the present invention, pickling in the present conditions is extremely important in order to control the surface roughness Rz of the steel sheet to 2.5μm greater, it is necessary to pickling under the above conditions. The acid is hydrochloric acid, generally an aqueous solution, such as sulfuric acid, it may be like aqua regia.
[0069]
　The temperature of the aqueous solution is less than 80 ° C. or higher 100 ° C., the slow reaction rate is less than 80 ° C., in order to take a long time to the surface roughness of the hot-rolled steel sheet in a proper range. On the other hand, heating at 100 ° C. or higher temperatures, the reaction of pickling boils solutions of those no problem, a dangerous from splashing it is not preferable.
[0070]
　Also, to that a concentration of acid 3 wt% to 20 wt% is to control the surface roughness Rz of the hot-rolled steel sheet in a proper range. The concentration of the acid is less than 3 wt%, it takes a long time to unevenness control of the surface by pickling. On the other hand, when the concentration of the acid is more than 20 wt%, greatly damage the pickling bath, the facility management becomes difficult unfavorably. A preferred range of concentration of the acid is in the range of 5 mass% to 15 mass%.
[0071]
　Furthermore, the pickling time was 30s or more, in order to impart a predetermined concavo-convex to (Rz> 2.5 [mu] m or more irregularities) stably in the steel sheet surface by pickling. Incidentally, if the pickling tank is divided into a plurality, although different concentration or temperature of individual pickling tank, some, or pickling time sum if the above condition is satisfied, the hot rolled the surface roughness Rz of the steel sheet may be in the range of the present invention. In addition, it may be performed by dividing the pickling multiple times. In the present inventors' experiments, with hydrochloric acid inhibitor containing, as long as it can control the surface roughness Rz by pickling, or be other acids such as hydrochloric acid, sulfuric acid, nitric acid or the like not using an inhibitor , it is possible to obtain the effects of the present invention or a composite thereof.
[0072]
　Also, irregularities formed by pickling hot-rolled steel sheet, temper rolling, cold rolling, or, since the remains even after performing annealing to control the pickling conditions, a plate surface after pickling it is extremely important to give the irregularities. Therefore, it may be carried out temper rolling the hot-rolled steel sheet after pickling.
[0073]
　Furthermore, cold-rolled steel sheet was subjected only to cold rolling, or even cold-rolled steel sheet was heat-treated after the cold rolling at continuous annealing equipment or box-type annealing furnace, by performing the pickling before cold rolling, the surface irregularities and by forming it is possible to obtain a predetermined effect. Incidentally, the roll roughness Rz for cold rolling is preferably pressed cold in the range of 1.0 .mu.m ~ 20.0 .mu.m, including roll is temper rolling the cold rolling roll.
[0074]
　The pickled hot-rolled steel sheet in the above-described conditions, subjected to cold rolling at a reduction ratio of 30% to 80% may be Tsuban the continuous annealing equipment. When the rolling reduction is less than 30%, it becomes difficult to maintain the shape of the steel sheet flat, and since the ductility of the final product is deteriorated, the lower limit of the rolling reduction is preferably 30%. On the other hand, when the reduction ratio exceeds 80%, the rolling load becomes too large, since the cold rolling becomes difficult, the upper limit of the rolling reduction is preferably 80%. More preferably a reduction ratio of 40% to 70%. Incidentally, the number of rolling passes, and the rolling reduction of each pass, without particularly specified, the effect of the present invention is expressed, the number of rolling passes, and rolling reduction per pass need not be specified.
[0075]
　Then, the cold-rolled steel sheet, may be Tsuban to the continuous annealing line. The purpose of this process, since it is possible to soften the high strength steel sheet by cold rolling the purpose, the steel sheet may be any condition as long as the conditions for softening. For example, if the range annealing temperature of 550 ° C. ~ 750 ° C., dislocations introduced during cold rolling, recovery, recrystallization, or because it is released by the phase transformation, be carried out annealing in this temperature range preferable.
[0076]
　For the same purpose, be subjected to annealing by box furnace, it is possible to obtain a steel sheet for hot stamping that excellent scale adhesion invention.
[0077]
　Then, carrying out the coating oil. Oiling method as electrostatic coating oil, spray, although a roll coater or the like is generally used, 50 mg / m 2 ~ 1500 mg / m 2 method is not limited as long ensured unction weight in the range of. In the present invention, it was performed oiling predetermined amount at electrostatic oiling machines. Further, 50 mg / m 2 ~ 1500 mg / m 2 if the oil coating weight in the range of can be secured, it may be degreased by oiled the more the amount of rust inhibitor.
[0078]
　Hot stamping conditions, it is possible to achieve both the excellent scale adhesion and corrosion resistance, which is the effect of the present invention without particular limitation. For example, it is produced by a manufacturing method described below, thereby to achieve both excellent performance and productivity of more tensile strength 1180 MPa. When performing hot stamping, to a temperature range of 800 ° C. ~ 1100 ° C., it is preferred to heat at 2 ° C. / sec or more heating speeds. By heating at 2 ° C. / sec or faster, it is possible to suppress scale formation during heating is effective in improving the scale adhesion. More preferably, the heating rate was 5 ° C. / sec or more, further preferably 10 ° C. / sec or more. Also, an increase rate of heating is also effective to increase productivity.
[0079]
　Annealing temperature for carrying out a hot stamp, preferably in the range of 800 ℃ ~ 1100 ℃. The annealing by performing in a temperature range, it is possible to austenite single-phase structure, it is possible to martensite tissue by cooling to be performed subsequently as a main phase tissue. The annealing temperature in this is below 800 ° C., a tensile strength of together with the tissue at the time of annealing is ferrite and austenite structure, this ferrite is grown in the cooling process, the ferrite volume fraction of 10% ultra next, hot stamping member but it falls below the 1180MPa. Therefore, the lower limit of the annealing temperature is preferably set at 800 ° C.. On the other hand, if the annealing temperature exceeds 1100 ° C., not only the effect is saturated, will greatly increase the scale thickness, there is a concern that the scale adhesion is decreased. Therefore, it is preferable to perform the annealing at 1100 ° C. or less. More preferably, the annealing temperature is in the range of 830 ℃ ~ 1050 ℃.
[0080]
　It may be performed held in a temperature range of 800 ° C. ~ 1100 ° C. after heating. When carrying out the retention at high temperatures, it is capable of dissolving the carbide contained in the steel sheet and contributes to improvement of strength increase and hardenability of the steel sheet. Holding and the residence in this temperature range, removing heat, and comprises a removal cooling. Since the dissolution of carbides is an object, if only ensure the residence time in this temperature range, the object is achieved. Although the retention time limit is not particularly provided, the scale thickness when the holding time is more than 1000s becomes excessive, it is preferable that the 1000s from the scale adhesion is degraded to the upper limit.
[0081]
　Thereafter, it is preferable to cool the 800 ° C. ~ 700 ° C. at an average cooling rate of more than 5 ° C. / sec. Here, 700 ° C. is the type cooling start temperature, is to a 800 ° C. ~ 700 ° C. The 5 ° C. / sec or more, ferrite transformation, bainite transformation, and avoiding pearlitic transformation, to organize and martensite main phase This is because. In cooling rate is less than 5 ° C. / sec, would be those soft tissues formation, it is difficult to secure a tensile strength of at least 1180 MPa. On the other hand, the upper limit of the cooling rate without specifically defined, the effect of the present invention is exhibited. 5 ° C. / sec to a 800 ° C. ~ 700 ° C. The temperature range for cooling the above, in this temperature range there is a possibility that the tissue to cause a reduction in strength such as ferrite is formed. Cooling at this time, not limited to continuous cooling, even when the holding and heating at this temperature range, when the average cooling rate is 5 ° C. / sec or more, the effect of the present invention is exhibited. Cooling method can exhibit the effects of the present invention without also particularly limited. That is, the cooling using a mold, be any combination a mold cooling water cooling, it is possible to exhibit the effect of the present invention.
Example
[0082]
　Next, a description will be given of an embodiment of the present invention, conditions in examples are an example of conditions adopted for confirming the workability and effects of the present invention, the present invention is, in this single condition example the present invention is not limited. The present invention does not depart from the gist of the present invention, as long as they achieve the object of the present invention, it is capable of adopting various conditions.
[0083]
　First, A ~ S shown in Table 1, casting a slab component composition of a ~ n, after once cooling to room temperature, carried out furnace at 220 minutes heating furnace temperature = 1230 ° C., the finish rolling temperature = hot rolling conducted at 920 ℃ ~ 960 ℃, was carried out winding at a temperature condition shown in Table 2.
[0084]
[Table 1]

[0085]
[Table 2]

[0086]
　It should be noted that the finishing thickness of hot-rolled steel sheet to be subjected to hot stamp as hot-rolled steel sheet, it was 1.6mm. On the other hand, the thickness of the hot rolled steel sheet subjected to cold rolling was 3.2 mm. Thereafter, a pickling carried out at Table 2 conditions, when performing cold rolling and the plate thickness of 50% (3.2mm → 1.6mm). Then, for some of the steel sheet, performs annealing in a continuous annealing equipment, was a cold-rolled steel sheet. Then, using the NOX-RUST503F (Parker Kosan), Munuriyu 6090Mg ~ / m 2 was coated NOX503F the (Parker Kosan) at electrostatic oiling machine oiling the hot-rolled steel sheet and cold-rolled steel sheet in the range of.
[0087]
　Thereafter, after cutting the steel plate into a predetermined size, subjected to conduction heating up to 900 ° C. at 50 ° C. / sec, performed the retention of 10 seconds at 900 ° C., then, subjected to cooling of the 10s, 650 ° C. or higher It was quenched by the heat during shallow draw die at temperature. The obtained was visually observed hot stamping molded article was a steel sheet excellent peeling without steel scale to the scale adhesion.
[0088]
　With respect to corrosion resistance, at room temperature, carried out 30 days retaining the steel sheet rust did not occur on the surface of the steel sheet was defined as steel sheet excellent in corrosion resistance. In addition, using a plate test specimen, subjected to hot stamping under the above conditions was evaluated tensile properties. The evaluation results are shown in Table 3.
[0089]
[table 3]

[0090]
　Tensile properties were taken specimens conforming to JIS Z 2201, a tensile test is performed in conformity with JIS Z 2241, the maximum tensile strength was measured. Maximum tensile strength of not less than 1180 MPa, and the molded article of the present invention.
[0091]
　Composition analysis of the scale of the molded body, cut out a plate from the bottom of the cylindrical portion of the shallow drawing test pieces were performed by X-ray diffraction. From the peak intensity ratio of the oxides was measured volume ratios of the Fe-based oxides. Si oxide is present very thin, since it volume ratio was less than 1%, quantitative evaluation of X-ray diffraction has been difficult. However, at the EPMA line analysis, to be present at the interface between the scale and the base steel was confirmed.
　Unevenness evaluation of the interface between the scale and the base steel formed in the molded body, after performing the polishing embedded steel plates cut out from the above position, was observed by SEM at 3000 times the cross section perpendicular to the rolling direction. And each specimen 5 field observation was measured number density of irregularities in the range of 0.2 [mu] m ~ 1.0 .mu.m per 100μm length.
[0092]
　Satisfy those of the present invention could achieve both good scale adhesion and excellent corrosion resistance. Does not satisfy the conditions of the invention is inferior to the scale adhesion, or poor corrosion resistance.
Industrial Applicability
[0093]
　According to the present invention, it can provide a steel sheet excellent in scale adhesion during hot stamping, wear of the mold at the time of hot stamping, plating adhesion to the mold, and can be solved with the push flaw problems associated therewith from, it is possible to bring about the improvement of significant productivity, industrial there is great value in.

The scope of the claims
[Claim 1]
　By
　mass%,
　C:
　0.100% ~ 0.600%, Si: 0.50% ~
　3.00%, Mn: 1.20% ~ 4.00%, Ti: 0.005% ~ 0.100
　%, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~
　1.000%, N: 0. 0100% or less,
　Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00
　Pasento, Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～
　2.00 Pasento, Nb: 0 Pasento ～ 0
　% .100, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% ~ 0.0300%
　contain a composition the balance being Fe and impurities, the Rz> 2.5 [mu] m surface roughness of the steel sheet, oiled on the surface 50 mg / m 2 ~ 1500 mg / m 2 for a steel sheet a hot stamp coating oil is characterized in that it is coated.
[Claim 2]
　Hot stamping steel sheet according to claim 1, wherein the amount of S contained in the coating fluid to be oiled in the steel sheet is not more than 5% in mass%.
[Claim 3]
　The composition of the steel sheet contains, by
　mass%, Ni:
　0.01% ~
　2.00%, Cu: 0.01% ~ 2.00%, Cr: 0.01% ~
　2.00%, Mo: 0.
　Pasento ～ 2.00 01 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100%,
selected from the group consisting of hot stamping steel sheet according to claim 1 or 2, characterized in that it contains one or two or more.
[Claim 4]
　The composition of the steel sheet contains, by
　mass%, claim that REM, Ca, characterized in that it contains 0.0003% - 0.0300% in total of one or more selected from the group consisting of Ce and Mg hot stamping steel sheet according to any one of 1 to 3.
[Claim 5]
　By
　mass%,
　C:
　0.100% ~ 0.600%, Si: 0.50% ~
　3.00%, Mn: 1.20% ~ 4.00%, Ti: 0.005% ~ 0.100
　%, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~
　1.000%, N: 0. 0100% or less,
　Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00
　Pasento, Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～
　2.00 Pasento, Nb: 0 Pasento ～ 0
　% .100, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% ~ 0.0300%
　containing, by casting a slab balance being Fe and impurities, directly or temporarily line hot rolling heat to after cooling There, a step of obtaining a hot-rolled steel sheet,
　the hot-rolled steel sheet, the temperature is 80 ° C. or more but less than 100 ° C., the concentration of acid in the inhibitor-containing is 3 mass% to 20 mass% of the pickling over 30 seconds with an aqueous solution a step of performing,
　the steps of applying a rust preventive oil to the steel sheet after carrying out the pickling
　has,
　a rust-preventive oil residual amount of the steel sheet surface 50 mg / m 2 ~ 1500 mg / m 2Method for producing a hot stamping steel plate, characterized in that to limit the.
[Claim 6]
　Method for producing a hot stamping steel sheet according to claim 5, characterized in that applying the rust preventive oil to the pickled hot-rolled steel sheet.
[Claim 7]
　Further comprising the step of obtaining a cold rolled steel sheet performed cold rolling the pickled hot-rolled steel sheet,
　hot according to claim 5, characterized in that applying the rust preventive oil to the cold-rolled steel sheet method of manufacturing a stamp for steel plate.
[8.]
　The pickled cold-rolled conducted in hot-rolled steel plate further has a further continuous annealing equipment or box-type annealing furnace at heat treatment is carried out to obtain a cold-rolled steel sheet step,
　the rust-preventive oil on the cold-rolled steel sheet method for producing a hot stamping steel sheet according to claim 5, wherein applying.
[Claim 9]
　Antirust oil applied to the steel sheet, a manufacturing method of hot stamping steel sheet according to any one of claims 5-8, characterized in that the S content is not more than 5% in mass%.
[Claim 10]
　The composition of the slab, in
　mass%, Ni:
　0.01% ~
　2.00%, Cu: 0.01% ~ 2.00%, Cr: 0.01% ~
　2.00%, Mo: 0.
　Pasento ～ 2.00 01 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100%,
selected from the group consisting of one or manufacturing method of hot stamping steel sheet according to any one of claims 5-9, characterized by containing two or more substances.
[Claim 11]
　The composition of the slab, in
　mass%, claim that REM, Ca, characterized in that it contains 0.0003% - 0.0300% in total of one or more selected from the group consisting of Ce and Mg method for producing a hot stamping steel sheet according to any one of 5-10.
[Claim 12]
　By
　mass%,
　C:
　0.100% ~ 0.600%, Si: 0.50% ~
　3.00%, Mn: 1.20% ~ 4.00%, Ti: 0.005% ~ 0.100
　%, B: 0.0005% ~
　0.0100%, P: 0.100% or
　less,
　S: 0.0001% ~ 0.0100%, Al: 0.005% ~
　1.000%, N: 0. 0100% or less,
　Ni: 0
　Pasento
　～ 2.00 Pasento, Cu: 0 Pasento ～ 2.00
　Pasento, Cr: 0 Pasento ～ 2.00 Pasento, Mo: 0 Pasento ～
　2.00 Pasento, Nb: 0 Pasento ～ 0
　% .100, V:
　0% ~ 0.100%, W: 0% ~ 0.100%, and
　REM, Ca, 1 or 2 or more in total selected from the group consisting of Ce and Mg: 0% ~ 0.0300%
　contain has the balance consisting of Fe and impurities, the interface between the scale and the base steel, the depth 0.2μm ~ 8.0μ Range and becomes uneven 100μm Atari of, there three or more, hot stamping molded tensile strength, characterized in that at least 1180 MPa.
[Claim 13]
　On the surface of the hot stamping material, Si oxide, FeO, Fe 3 O 4 , and Fe 2 O 3 has a hot set forth in claim 12, wherein the thickness of the scale is 10μm or less stamping body.
[Claim 14]
　The composition of the hot stamping molded article, in
　mass%, Ni:
　0.01% ~
　2.00%, Cu: 0.01% ~ 2.00%, Cr: 0.01% ~
　2.00%, Mo :
　0.01 Pasento ～ 2.00 Pasento,
　Nb: 0.005 Pasento ～ 0.100 Pasento, V: 0.005 Pasento ～ 0.100 Pasento, and
　W: 0.005% ~ 0.100%,
consisting of hot stamping molded article according to claim 12 or 13, characterized in that it contains one or more kinds selected from the group.
[Claim 15]
　Wherein the composition of the hot stamping material, by
　mass%, and wherein REM, Ca, in that it contains 0.0003% - 0.0300% in total of one or two or more selected from the group consisting of Ce and Mg hot stamping molded article according to any one of claims 12 to 14.