Specification
Title of invention: Fe-Al based hot stamping member and method for manufacturing Fe-Al based hot stamping member
Technical field
[0001]
　TECHNICAL FIELD The present invention relates to an Fe—Al-based hot stamping member and a method for manufacturing an Fe—Al-based hot stamping member.
Background technology
[0002]
　In recent years, in applications of automobile steel sheets (for example, automobile pillars, door impact beams, bumper beams, etc.), steel sheets having both high strength and high formability have been desired. One of the steel sheets that meets such a demand is TRIP (Transformation Induced Plasticity) steel that utilizes the martensitic transformation of retained austenite. With this TRIP steel, it is possible to manufacture a high-strength steel sheet having excellent formability and strength of about 1000 MPa class. However, it is difficult to secure formability with ultra-high-strength steel having a higher strength (for example, 1500 MPa or more), and there is a problem that the shape fixability after forming is poor and the dimensional accuracy of the formed product is poor.
[0003]
　As described above, in contrast to the method of forming at around room temperature (so-called cold press method), a method that has recently attracted attention is also called hot stamping (hot press, hot press, die quench, press quench, etc.). ). This hot stamping secures the ductility of the material by hot press forming immediately after heating the steel plate to the austenite range of 800°C or higher, and quenches the material by quenching with a mold while holding the bottom dead center. And a desired high-strength material is obtained after pressing. According to this construction method, it is possible to obtain an automobile member having excellent shape fixability after molding.
[0004]
　The hot stamp as described above is promising as a method for molding an ultrahigh-strength member, but has a problem of scale generated during heating. Hot stamping usually has a step of heating a steel sheet in the atmosphere, and at this time, an oxide (scale) is formed on the surface of the steel sheet. The generated scale causes a decrease in the adhesion of the electrodeposition coating film and a decrease in the corrosion resistance after coating, so that a step of removing the scale is required, and the productivity of the member is reduced.
[0005]
　As a technique for improving the above scale problem and enhancing the corrosion resistance of hot stamped products, for example, in Patent Document 1 below, by using a Zn-based plated steel plate as a steel plate for hot stamping, Techniques for suppressing scale generation have been proposed.
[0006]
　However, since Zn used in the technique proposed in Patent Document 1 is a metal having a low melting point, when a Zn-based plated steel sheet is used as a hot stamp, liquid metal embrittlement during hot press forming ( Liquid metal embrittlement (LME) may be caused, and there is a problem that the collision resistance of the automobile member is deteriorated.
[0007]
　Therefore, for example, in Patent Documents 2 to 4 below, an Al-based plated steel sheet using Al, which is a metal having a relatively high melting point and excellent in oxidation resistance, is used to improve the problem of scale, and Techniques for solving problems have been proposed.
Prior art documents
Patent literature
[0008]
Patent Document 1: Japanese Patent Laid-Open No. 9-202953
Patent Document 2: Japanese Patent Laid-Open No. 2003-181549
Patent Document 3: Japanese Patent Laid-Open No. 2007-314874
Patent Document 4: Japanese Patent Laid-Open No. 2009-263692
Summary of the invention
Problems to be Solved by the Invention
[0009]
　However, when an Al-based plated steel sheet as proposed in Patent Documents 2 to 4 is used as a hot stamp, the steel sheet is exposed to a high temperature of 800° C. or higher, so that Fe in the steel sheet reaches the surface of the plating. As a result of diffusion, the Al plating layer is changed to a Fe—Al based intermetallic compound Fe—Al based plating layer which is hard and brittle. As a result, during hot press forming, cracks or powdery peeling may occur in the plated layer, and the corrosion resistance of the formed part may decrease. The Fe-Al-based plating layer here means a plating layer in which Fe diffuses by 40 mass% or more during plating and the Al content is 60 mass% or less.
[0010]
　Here, the deterioration of the corrosion resistance of the above-mentioned molded part is more specifically "after hot stamping so as to be a hat type, before being used as an automobile part, a phosphoric acid conversion treatment which is a general treatment, It is considered that this is caused by the phenomenon that "corrosion after the electrodeposition coating treatment causes red rust to be generated more quickly from the bent R portion of the molded portion."
[0011]
　Further, since Al oxide is formed on the Fe-Al-based plating layer, the reactivity with the processing solution of the phosphoric acid conversion treatment is hindered, and the adhesion of the electrodeposition coating film after the electrodeposition coating treatment is lowered. Then, the corrosion resistance after coating may be reduced. Here, more specifically, the deterioration of the corrosion resistance after painting is described as "after hot stamping, phosphoric acid conversion treatment and electrodeposition coating treatment are performed, and a flaw is imparted to the coating film by a cutter (simulating the flaw due to chipping etc.) It is considered that this is caused by the phenomenon that "corrosion afterwards makes it easier for corrosion swelling (Blister) of the coating film to spread from the flaw".
[0012]
　As described above, even when the techniques proposed in Patent Documents 2 to 4 are used, there is still room for improvement in the corrosion resistance of the molded portion after hot stamping and the corrosion resistance after coating.
[0013]
　Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a Fe-Al-based plated hot stamp member and an Fe-Al-based hot stamp member exhibiting superior corrosion resistance of a molded part and corrosion resistance after coating. An object is to provide a method for manufacturing an Al-based plated hot stamp member.
Means for solving the problem
[0014]
　As a result of intensive studies to solve the above problems, the present inventors have found that even if the plating has cracks or powdery peeling during molding, Al of the Fe--Al-based plating layer, It has been found that by appropriately controlling the Fe composition, the reactivity of phosphorylation is promoted and the adhesion of the electrodeposition coating film is secured to improve the corrosion resistance of the formed part. Further, the corrosion of the flaws of the electrodeposition coating film is caused by containing Mn and Si in the three layers A, B and C which are located on the surface side of the Fe—Al based plating layer, and With respect to the composition, it has been found that the deviation of the A layer, the B layer, and the C layer can suppress the spread of the coating swelling due to the corrosion from the flaw.
　The gist of the present invention completed based on the above findings is as follows.
[0015]
[1] It has a Fe—Al-based plating layer located on one side or both sides of the base material, and the base material is C: 0.1% or more and 0.5% or less, Si:0 in mass %. 0.01% or more and 2.00% or less, Mn: 0.3% or more and 5.0% or less, P: 0.001% or more and 0.100% or less, S: 0.0001% or more and 0.100% or less, Al : 0.01% to 0.50%, Cr: 0.01% to 2.00%, B: 0.0002% to 0.0100%, N: 0.001% to 0.010% And the balance consists of Fe and impurities, and the Fe—Al based plating layer has a thickness of 10 μm or more and 60 μm or less, and is A layer, B layer, C in order from the surface toward the base material. Fe-Al intermetallic compound containing the following components in a total of 100% by mass or less, and the balance being impurities. made, the D layer is further cross-sectional area 3 [mu] m 2 or more 30 [mu] m 2 of Kirkendall voids is less than (Kirkendall void), 10 pieces / 6000 .mu.m 2 or 40/6000 .mu.m 2 containing less, Fe-Al-based plated Hot stamping material.
　A layer and C layer
　　Al: 40 mass% or more and 60 mass% or less
　　Fe: 40 mass% or more and less than 60 mass%
　　Si: 5 mass% or less (not including 0 mass%)
　　Mn: less than 0.5 mass% (0 Does not include mass %.)
　　Cr: less than 0.4% by mass (not including 0% by mass)
　B layer
　　Al: 20% by mass or more and less than 40% by mass
　　Fe: 50% by mass or more and less than 80% by mass
　　Si: more than 5% by mass and 15% by mass or less
　　Mn : 0.5 mass% or more and 10 mass% or less
　　Cr: 0.4 mass% or more and 4 mass% or less
　D layer
　　Al: Less than 20 mass% (0 mass% is not included)
　　Fe: 60 mass% or more and less than 100 mass%
　　Si: 5 mass% or less (0 mass% is not included)
　　Mn: 0.5 mass% or more and 2.0 mass% or less
　　Cr: 0.4 mass% or more and 4 mass% or less
[2] On the surface of the A layer The Fe-Al-based hot stamping member according to [1], further including an oxide layer having a thickness of 0.1 μm or more and 3 μm or less made of an oxide of Mg, Mg, and/or Ca.
[3] The base material is, in place of a part of the balance Fe, replaced by mass% W: 0.01 to 3.00%, Mo: 0.01 to 3.00%, V: 0.01 to 2.00%, Ti: 0.005 to 0.500%, Nb: 0.01 to 1.00%, Ni: 0.01 to 5.00%, Cu: 0.01 to 3.00%, Co : 0.01 to 3.00%, Sn: 0.005 to 0.300%, Sb: 0.005 to 0.100%, Ca: 0.0001 to 0.01%, Mg: 0.0001 to 0 0.01%, Zr: 0.0001 to 0.01%, REM: 0.0001 to 0.01%, and the Fe-Al plating hot according to [1] or [2]. Stamp member.
[4] C: 0.1% or more and 0.5% or less, Si: 0.01% or more and 2.00% or less, Mn: 0.3% or more and 5.0% or less, P: 0. 001% to 0.100%, S: 0.0001% to 0.100%, Al: 0.01% to 0.50%, Cr: 0.01% to 2.00%, B: A steel slab containing 0.0002% or more and 0.0100% or less, N: 0.001% or more and 0.010% or less, and the balance having a base material component composed of Fe and impurities was hot-rolled and acid-treated. After blanking a steel sheet that has been washed, cold-rolled, and then continuously annealed and hot-dip aluminized, the heating time from when the steel sheet after blanking is put into the heating equipment to when it is taken out is 150 seconds or more. The steel sheet after blanking is heated at 850° C. or more and 1050° C. or less for 650 seconds or less, immediately after that, formed into a desired shape, and rapidly cooled at a cooling rate of 30° C./second or more. The composition of the molten aluminum plating bath used for plating is Al: 80 mass% or more and 96 mass% or less, Si: 3 mass% or more and 15 mass% or less, Fe: 1 mass% or more and 5 mass% or less, and the total is 100 mass% or less. And the balance consists of impurities. Regarding the steel plate temperature Y (° C.) and the heating time X (seconds) in the heating, Y is 600° C. or more and 800° C. or less, the heating time X is 100 seconds or more and 300 seconds or more. If the first derivative (dY/dX) of Y with respect to the steel plate temperature Y is 0 or less with respect to the steel plate temperature Y, control is performed so that Y exists within the range of 600° C. or more and 800° C. or less, Fe -A method for producing an Al-plated hot stamp member.
[5] The composition of the molten aluminum plating bath further contains at least either Mg or Ca in a total amount of 0.02% by mass or more and 3% by mass or less, and the Fe—Al-based plating hot according to [4]. Stamp member manufacturing method.
[6] In the slab, W: 0.01 to 3.00%, Mo: 0.01 to 3.00%, V: 0.01 to 2.00%, Ti: 0.005 to 0.500%, Nb: 0.01 to 1.00%, Ni: 0.01 to 5.00%, Cu: 0.01 to 3. 00%, Co: 0.01 to 3.00%, Sn: 0.005 to 0.300%, Sb: 0.005 to 0.100%, Ca: 0.0001 to 0.01%, Mg: 0 Fe-according to [4] or [5], further containing at least one of 0.0001 to 0.01%, Zr: 0.0001 to 0.01%, and REM: 0.0001 to 0.01%. A method for manufacturing an Al-based plated hot stamp member.
Effect of the invention
[0016]
　As described above, according to the present invention, it is possible to obtain the Fe—Al-based hot stamp member and the Fe—Al-based hot stamp member that exhibit more excellent corrosion resistance of the molded part and corrosion resistance after coating.
Brief description of the drawings
[0017]
FIG. 1 is a cross-sectional observation photograph of the Fe—Al-based plating of the Fe—Al-based plated high-strength hot stamped steel sheet of the invention example of the present application, showing layers A to D in the Fe—Al-based plating layer, Kirkendall voids and the drawing. It is a figure showing EDS analysis points of 2, 3, and 4.
FIG. 2 is a diagram showing Al and Fe compositions of Fe—Al based plating obtained from EDS analysis of plating of Fe—Al based plated hot stamped steel sheet of the invention example of the present application. Areas shaded in gray are within the scope of the present invention.
FIG. 3 is a diagram showing the Al and Si compositions of the Fe—Al based plating obtained from the EDS analysis of the plating of the Fe—Al based plated hot stamped steel sheet of the invention example of the present application. Areas shaded in gray are within the scope of the present invention.
FIG. 4 is a diagram showing Al and Mn compositions of Fe—Al based plating obtained from EDS analysis of the plating of the Fe—Al based plated hot stamped steel sheet of the invention example of the present application. Areas shaded in gray are within the scope of the present invention.
FIG. 5 is a plating cross section of an example of the invention of the present application, showing a method for measuring the number density of Kirkendall voids and the measurement results thereof.
MODE FOR CARRYING OUT THE INVENTION
[0018]
　Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0019]

　The Fe—Al system high strength hot stamping member according to the embodiment of the present invention (hereinafter, also simply referred to as “hot stamping member”) is a steel plate that is a base material. Has an Fe-Al based plating layer on one or both sides. The Vickers hardness (JIS Z 2244, load 9.8 N) of the hot stamp member according to the present embodiment is 300 HV or more. Hereinafter, the base material and the Fe—Al based plating layer included in the hot stamp member according to the present embodiment will be described in detail.
[0020]
(About Base Material)
　First, the base material components in the hot stamp member according to the present embodiment will be described in detail. In addition, in the following description,% about a component means the mass %.
[0021]
　As described above, the hot stamping is performed by hot pressing and quenching with a mold at the same time. Therefore, the hot stamping member according to the present embodiment has high hardenability. Must be a component system.
[0022]
　Therefore, the base material component of the hot stamp member according to the present embodiment is, in mass %, C: 0.1% or more and 0.5% or less, Si: 0.01% or more and 2.00% or less, Mn: 0. 3% to 5.0%, P: 0.001% to 0.100%, S: 0.001% to 0.100%, Al: 0.01% to 0.50%, Cr: 0.01% or more and 2.00% or less, B: 0.0002% or more and 0.0100% or less, N: 0.001% or more and 0.010% or less, and the balance consists of Fe and impurities.
[0023]
[C: 0.1% or more and 0.5% or less] The
　present invention provides a molded part (hot stamping member) having a high strength of Vickers hardness of 300 HV or more after hot stamping. It is required to quench and transform into a structure mainly composed of martensite. Therefore, from the viewpoint of improving hardenability, the content of C (carbon) needs to be at least 0.1% or more. The C content is preferably 0.15% or more. On the other hand, when the content of C is too large, the toughness and ductility of the steel sheet are significantly deteriorated, so that cracking occurs during hot stamping. Such a decrease in toughness and ductility becomes remarkable when the C content exceeds 0.5%, so the C content is set to 0.5% or less. The C content is preferably 0.40% or less.
[0024]
[Si: 0.01% or more and 2.00% or less]
　Si (silicon) has an effect of improving the corrosion resistance of the Fe—Al-based plating layer by diffusing during plating by heating during hot stamping. Since such improvement in corrosion resistance is exhibited when the Si content is 0.01% or more, the Si content is set to 0.01% or more. The Si content is preferably 0.05% or more, more preferably 0.1% or more. On the other hand, Si is an element that is more easily oxidized than Fe (oxidizable element). Therefore, in the continuous annealing plating line, a stable Si-based oxide film is formed on the surface of the steel sheet during the annealing treatment. However, if Si is excessively contained, the adhesion of the plating during the molten Al plating treatment is hindered and the non-plating is performed. Occurs. Therefore, from the viewpoint of suppressing non-plating, the Si content is 2.0% or less. The Si content is preferably 1.80% or less, more preferably 1.50% or less.
[0025]
[Mn: 0.3% or more and 5.0% or less]
　Mn (manganese) diffuses during plating by heating during hot stamping, and has the effect of improving the corrosion resistance of the Fe-Al-based plating layer. Since the effect of improving the corrosion resistance is exhibited when the Mn content is 0.3% or more, the Mn content is set to 0.3% or more. Further, by setting the content of Mn to 0.3% or more, the hardenability of the base material can be enhanced and the strength after hot stamping can also be improved. The Mn content is preferably 0.5% or more, more preferably 0.7% or more. On the other hand, the excessive Mn content deteriorates the impact properties of the member after quenching. Such a decrease in impact properties occurs when the Mn content exceeds 5.0%, so the Mn content is set to 5.0% or less. The Mn content is preferably 3.0% or less, more preferably 2.5% or less.
[0026]
[P: 0.001% or more and 0.100% or less]
　P (phosphorus) is an element that is inevitably contained, but is also a solution strengthening element, and it is to increase the strength of the steel sheet at a relatively low cost. You can If the P content exceeds 0.100%, adverse effects such as a decrease in toughness occur, so the P content is set to 0.100% or less. The P content is preferably 0.050% or less. On the other hand, the lower limit of the P content is not particularly limited, but if the P content is made to be less than 0.001%, it is not economical from the viewpoint of refining limit. Therefore, the P content is set to 0.001% or more. The content of P is preferably 0.005% or more.
[0027]
[S: 0.0001% or more and 0.100% or less]
　S (sulfur) is an element that is unavoidably contained, reacts with Mn in steel, and becomes MnS inclusions in the steel. When the content of S exceeds 0.100%, the generated MnS serves as a starting point of fracture, impairs ductility and toughness, and deteriorates workability. Therefore, the S content is 0.100% or less. The content of S is preferably 0.010% or less. On the other hand, the lower limit of the S content is not particularly limited, but if the S content is made less than 0.0001%, it is not economical from the viewpoint of refining limit. Therefore, the S content is set to 0.001% or more. The content of S is preferably 0.0005% or more, more preferably 0.001% or more.
[0028]
[Al: 0.01% or more and 0.50% or less]
　Al (aluminum) is contained in steel as a deoxidizing agent. Al is an element that is more easily oxidized than Fe (oxidizable element). When the content of Al exceeds 0.50%, a stable Al-based oxide film is formed on the surface of the steel sheet during the annealing treatment, which hinders the adhesion of the molten Al plating and causes non-plating. Therefore, the Al content is 0.50% or less from the viewpoint of suppressing non-plating. The Al content is preferably 0.30% or less. On the other hand, the lower limit of the Al content is not particularly limited, but if the Al content is attempted to be less than 0.01%, it is not economical from the viewpoint of refining limit. Therefore, the content of Al is set to 0.01% or more. The Al content is preferably 0.02% or more.
[0029]
[Cr: 0.01% or more and 2.00% or less]
　Cr (chromium) has an effect of improving the hardenability of the steel sheet, like Mn. Since the effect of improving the hardenability is exhibited when the Cr content is 0.01% or more, the Cr content is 0.01% or more. Furthermore, by setting the Cr content to be 0.01% or more, Cr diffuses during plating by heating during hot stamping, and an effect of improving the corrosion resistance of the Fe—Al based plated layer is exhibited. The content of Cr is preferably 0.05% or more, more preferably 0.1% or more. On the other hand, Cr is an element that is more easily oxidized than Fe (oxidizable element). When the content of Cr exceeds 2.0%, a stable Cr-based oxide film is formed on the surface of the steel sheet during the annealing treatment, which inhibits the adhesion of the plating during the hot-dip Al plating treatment, resulting in non-plating. Therefore, from the viewpoint of suppressing non-plating, the content of Cr is set to 2.0% or less. The content of Cr is preferably 1.00% or less.
[0030]
[B: 0.0002% or More and 0.0100% or Less]
　B (boron) is a useful element from the viewpoint of hardenability, and by setting the content of B to 0.0002% or more, the hardenability The improvement effect is exhibited. Therefore, the content of B is set to 0.0002% or more. The content of B is preferably 0.0005% or more. On the other hand, even if B is contained in an amount of more than 0.0100%, the effect of improving the hardenability is saturated, and the castability and cracking during hot rolling are caused, thus lowering the productivity. Therefore, the content of B is set to 0.0100% or less. The content of B is preferably 0.0050% or less.
[0031]
[N: 0.001% or more and 0.010% or less]
　N (nitrogen) is an element that is unavoidably contained, and it is desirable to fix it in steel from the viewpoint of stabilizing the characteristics. N can be fixed by Al, Ti, Nb, etc. which are selectively contained. However, if the content of N increases, the amount of elements contained for fixing becomes large and the cost increases. Therefore, the content of N is set to 0.010% or less. The N content is preferably 0.008% or less. On the other hand, the lower limit of the N content is not particularly limited, but if the N content is set to be less than 0.001%, it is not economical from the viewpoint of refining limit. Therefore, the content of N is set to 0.001% or more. The content of N is preferably 0.002% or more.
[0032]
　Further, in the following, an element that can be selectively contained in the base material in place of the balance Fe will be described.
　In the base material according to the present embodiment, W: 0.01 to 3.00%, Mo: 0.01 to 3.00%, V: 0.01 by mass% in place of a part of the remaining Fe. Up to 2.00%, Ti: 0.005 to 0.500%, Nb: 0.01 to 1.00%, Ni: 0.01 to 5.00%, Cu: 0.01 to 3.00%, Co: 0.01 to 3.00%, Sn: 0.005 to 0.300%, Sb: 0.005 to 0.100%, Ca: 0.0001 to 0.01%, Mg: 0.0001 to At least one of 0.01%, Zr: 0.0001 to 0.01% and REM: 0.0001 to 0.01% may be further contained.
[0033]
[W, Mo: 0.01% or more and 3.00% or less]
　W (tungsten) and Mo (molybdenum) are elements useful from the viewpoint of hardenability, and are included from the viewpoint of improving hardenability. May be. The effect of improving the hardenability is exhibited when the content of each element is 0.01% or more. Therefore, the W and Mo contents are preferably 0.01% or more. However, even if each element is contained in an amount of more than 3.00%, the effect of improving the hardenability is saturated and the cost also increases. Therefore, the W and Mo contents are 3.00% or less, respectively. Preferably.
[0034]
[V: 0.01% or more and 2.00% or less]
　V (vanadium) is a useful element from the viewpoint of hardenability, and may be contained from the viewpoint of improving hardenability. The effect of improving the hardenability is exhibited when the content of each element is 0.01% or more. However, even if V is contained in an amount of more than 2.00%, the effect of improving the hardenability is saturated and the cost is increased. Therefore, the content of V is preferably 2.00% or less. ..
[0035]
[Ti: 0.005% to 0.500%]
　Ti (titanium) may be contained from the viewpoint of fixing N. When N is fixed using Ti, it is required to contain about 3.4 times the content of N in mass %, but the content of N is about 10 ppm even if it is reduced. Therefore, the lower limit of the Ti content may be 0.005%, for example. On the other hand, if Ti is excessively contained, the hardenability is lowered and the strength is also lowered. Such a decrease in hardenability and strength becomes significant when the Ti content exceeds 0.500%, so the Ti content is preferably 0.500% or less.
[0036]
[Nb: 0.01% or more and 1.00% or less]
　Nb (niobium) may be contained from the viewpoint of fixing N. When N is fixed using Nb, it is required to contain about 6.6 times the content of N in mass %, but the content of N is about 10 ppm even if it is reduced. Therefore, the lower limit of the Nb content may be, for example, 0.01%. On the other hand, when Nb is excessively contained, the hardenability is lowered and the strength is also lowered. Such a decrease in hardenability and strength becomes remarkable when the Nb content exceeds 1.00%, so the Nb content is preferably 1.00% or less.
[0037]
　Further, even if Ni, Cu, Sn, Sb or the like is contained as the base material component in addition to the above-mentioned selective elements, the effect of the present invention is not impaired.
[0038]
[Ni: 0.01 to 5.00%]
　Ni (nickel) is a useful element from the viewpoint of low-temperature toughness that leads to improvement of impact resistance in addition to hardenability, and may be contained. The effect of improving the hardenability and the low temperature toughness is exhibited when the Ni content is 0.01% or more. Therefore, the Ni content is preferably 0.01% or more. However, even if Ni is contained in excess of 5.00%, such an effect is saturated and the cost also increases. Therefore, the Ni content is preferably 5.00% or less.
[0039]
[Cu: 0.01 to 3.00%, Co: 0.01 to 3.00%]
　Like Ni, Cu (copper) and Co (cobalt) are useful in terms of toughness in addition to hardenability. It is an element and may be contained. The effect of improving the hardenability and toughness is exhibited when the contents of Cu and Co are each 0.01% or more. Therefore, the content of Cu and Co is preferably 0.01% or more. However, even if Cu or Co is contained in an amount of more than 3.00%, such an effect is saturated, and not only the cost is increased, but also the slab property is deteriorated and cracks and flaws are generated during hot rolling. Therefore, the Cu and Co contents are preferably 3.00% or less.
[0040]
[Sn: 0.005% to 0.300%, Sb: 0.005% to 0.100%] Both
　Sn (tin) and Sb (antimony) improve the wettability and adhesion of the plating. It is an effective element and may be contained. The effect of improving the wettability and adhesiveness of the plating appears when the content of each element is 0.005% or more. Therefore, the Sn and Sb contents are preferably 0.005% or more. However, when Sn is contained in an amount of more than 0.300% or when Sb is contained in an amount of more than 0.100%, a flaw during manufacturing is likely to occur or toughness is deteriorated. Or Therefore, the Sn content is preferably 0.300% or less, and the Sb content is preferably 0.100% or less.
[0041]
[Ca: 0.0001 to 0.01%, Mg: 0.0001 to 0.01%, Zr: 0.0001 to 0.01%, REM: 0.0001 to 0.01%]
　Ca (calcium), Mg (magnesium), Zr (zirconium), and REM (rare earth metal) have a content of 0.0001% or more, respectively, and are effective in reducing the size of inclusions. Therefore, the content of Ca, Mg, Zr, and REM is preferably 0.0001% or more. On the other hand, when the content of each element exceeds 0.01%, the above effect is saturated. Therefore, the content of each of Ca, Mg, Zr, and REM is preferably 0.01% or less.
[0042]
　In this embodiment, other components of the base material are not particularly specified. For example, elements such as As (arsenic) may be mixed from scrap, but within the normal range, the characteristics of the base material are not affected.
[0043]
(Fe—Al System Plating Layer)
　Next, the Fe—Al system plating layer, which is the most important in the present invention, will be described in detail.
[0044]
　The thickness of the Fe—Al based plating layer according to this embodiment is 10 μm or more and 60 μm or less. When the thickness of the Fe—Al based plating layer is less than 10 μm, the corrosion resistance of the molded part and the corrosion resistance after coating are deteriorated. On the other hand, when the thickness of the Fe-Al-based plating layer exceeds 60 μm, the plating layer is thick and the shearing force that the plating receives from the mold during hot stamping and the stress during compression deformation are large, and the plating layer peels off. As a result, the corrosion resistance of the molded part and the corrosion resistance after coating are reduced. The thickness of the Fe—Al based plating layer is preferably 15 μm or more, more preferably 20 μm or more. The thickness of the Fe—Al based plating layer is preferably 55 μm or less, more preferably 50 μm or less.
[0045]
　The “Fe—Al-based plating layer” here means a plating layer composed of an Fe—Al-based intermetallic compound and impurities that are inevitably contained. Specific examples of Fe—Al-based intermetallic compounds include, for example, Fe 2 Al 5 , FeAl 2 , FeAl (also called ordered BCC), α-Fe (also called irregular BCC), and Al solid solution α-. Fe, a solid solution of Si in these compositions, and a detailed stoichiometric composition may not be specified, but an Al-Fe-Si ternary alloy composition, etc. (12 types of τ1 to τ12 are specified. In particular, τ5 is also called an α phase, and τ6 is also called a β phase.). Examples of the unavoidable impurities contained in the Fe—Al-based plating layer include components such as stainless steel, ceramics, and thermal spray coatings of these materials that are commonly used as hot dip plating equipment during hot dipping. However, when Zn is contained in the Al plating bath, Zn contained in the Fe—Al-based plating layer is preferably 10% by mass or less, and preferably 3% by mass, for the reason of suppressing LME at the time of hot stamping described above. The following is more preferable.
[0046]
　In the hot stamp member according to the present embodiment, the Fe—Al-based plating layer as described above is composed of four layers of A layer, B layer, C layer, and D layer in this order from the surface toward the base material. The lower layer of the D layer is a base material. These four layers are observed with a scanning electron microscope (SEM) from the cross section without polishing the cross section of the plating and performing etching, and are 1000-fold composition images (also referred to as backscattered electron beam images). Since the contrast after shooting is divided into four types, it is possible to specify and distinguish. The results of observing the cross section of the Fe—Al based plated layer according to the present invention are shown in FIG. 1 as an example.
[0047]
　In FIG. 1, first, a martensite structure is formed in the base material. Since it is not etched in this figure, it is not clear that it has a martensite structure, but when the Vickers hardness (load 9.8N) was measured, it was a high hardness of HV 400 or higher that suggests a martensite structure. The light gray contrast layer adjacent to the matrix is ​​then the D layer. The layer formed on the surface side of the D layer and adjacent to the D layer and having a dark gray contrast is the C layer. Further, the light gray contrast layer on the surface side adjacent to the C layer is the B layer, and the dark gray layer on the most surface side adjacent to the B layer is the A layer. As another observation example, the B layer may be intermittent and the A layer and the C layer may not be distinguished, but such a case is also within the scope of the present invention, and the corrosion resistance of the molded part and the corrosion resistance after coating are There is no effect on the above. Note that the contrast density is an example, and if distinguished as four layers, it has a four-layer structure within the scope of the present application.
[0048]
　As a method for specifying the composition of each of the A layer, the B layer, the C layer, and the D layer forming the Fe—Al plated layer, the following method can be exemplified. That is, the plating is cross-section polished and etching is not performed, and the cross-section is observed as a composition image with an electron beam microanalyzer (EPMA) at a magnification of 1000 to perform elemental analysis. After the A layer, the B layer, the C layer, and the D layer are specified and distinguished by the above-described method, the composition analysis of the A layer, the B layer, the C layer, and the D layer is performed, and the total of Al, Fe, Si, Mn, and Cr is calculated. It can be obtained from the quantitative analysis result with the content of 100%. In each layer, composition analysis is performed at two or more points, and the average value of the obtained analysis values ​​is taken as the composition of the layer.
[0049]
　The composition of each of the A layer, the B layer, the C layer, and the D layer is as follows. In addition,% of the following composition is mass %, and each layer contains the following components so that the total is 100 mass% or less, and the balance is impurities.
[0050]
　A layer and C layer
　　Al: 40 mass% or more and 60 mass% or less
　　Fe: 40 mass% or more and less than 60 mass%
　　Si: 5 mass% or less (not including 0 mass%)
　　Mn: less than 0.5 mass% (0 Mass% is not included.)
　　Cr: less than 0.4 mass% (excluding 0 mass%)
　B layer
　　Al: 20 mass% or more and less than 40 mass%
　　Fe: 50 mass% or more and less than 80 mass%
　　Si: 5 mass % Over 15% by mass
　　Mn: 0.5% by mass or more and 10% by mass or less
　　Cr: 0.4% by mass or more and 4% by mass or less
　D layer
　　Al: less than 20% by mass (excluding 0% by mass)
　　Fe: 60 % by mass % Or more and less than 100 mass%
　　Si: 5 mass% or less (0 mass% is not included)
　　Mn: 0.5 mass% or more and 2 mass% or less
　　Cr: 0.4 mass% or more and 4 mass% or less
[0051]
　The first role of the Fe—Al based plating layer is to improve the possibility of corrosion resistance of the formed part. As described above, when an Al-based plated steel sheet is used as a hot stamp, since it is exposed to a high temperature of 800° C. or higher, Fe diffuses to the surface of the plating, and the plating layer is hard and brittle. The Fe-Al-based plating layer made of a compound changes. As a result, during hot press forming, cracks and powdery peeling occur in the plating, and the corrosion resistance of the formed part decreases. More specifically, the possibility of corrosion resistance of the molded part means that, when the hat mold is hot stamped, and then subjected to phosphoric acid conversion treatment and electrodeposition coating treatment and then corroded, red rust is generated from the bent R portion of the molded part. Is likely to be faster.
[0052]
　As a result of diligent studies on the above possibility, the inventors of the present application have found that the red rust from the bent R portion of the formed part is caused by the rust originating from the crack generated in the forming of the Fe—Al-based plating layer. It was In addition, the inventors of the present invention, in order to suppress the occurrence of such rust, Al: 60 mass% or less for all the compositions of the A layer, the B layer, the C layer, and the D layer of the Fe—Al-based plating layer, and It was found that it is important to set Fe: 40% by mass or more and further contain Si, Mn and Cr.
[0053]
　The reason why it is possible to suppress the generation of rust originating from cracks with such a composition is not clear yet, but it is estimated as follows. That is, the composition of the Fe—Al-based plating layer as described above dramatically improves the reactivity of the phosphoric acid conversion treatment, and as a result, a dense film of phosphoric acid conversion crystals is formed and the formed dense layer is formed. It is presumed that such a film acts as a barrier layer against corrosion and suppresses the generation of rust on the Fe—Al based plating layer.
[0054]
　In general, since an inactive aluminum oxide film generated by heating is formed on the surface of the hot stamped Fe—Al-based plating layer, it is difficult to form phosphoric acid conversion crystals. However, cracks occur in the plating at the bent R portion during molding, and since such cracks are formed after heating by the hot stamp, the amount of aluminum oxide film is small and phosphoric acid conversion crystals are relatively easy to form. As a result, by controlling the composition of the Fe—Al based plating layer according to the present embodiment, the reactivity of the phosphoric acid conversion treatment is dramatically improved, which causes corrosion of cracks in the Fe—Al based plating layer. It is considered that this is suppressed and the corrosion resistance of the molded part is improved.
[0055]
　Therefore, in the crack of the Fe—Al based plating composition as described above, the phosphoric acid conversion crystals are favorably formed in the A layer, the B layer, the C layer and the D layer. The phosphoric acid conversion crystal is a crystal formed by a general phosphoric acid conversion treatment for automobile parts, and is a crystal that improves the adhesion of electrodeposition coating after chemical conversion treatment and, as a result, also improves the corrosion resistance after coating. Is. Although rust progresses from the surface, as described above, from the viewpoint of corrosion resistance of the formed part, since it is a rust originating from a crack generated in the Al—Fe-based plating layer, the B layer other than the A layer on the outermost surface, the C layer It is particularly important to control the composition of the layers and D layers to the above-mentioned composition.
[0056]
　As described above, the composition of the Fe-Al-based plating layer is Al: 60% by mass or less and Fe: 40% by mass or more, and further contains Si, Mn, and Cr, so that the reactivity of phosphoric oxidation is improved. Be promoted. The cause of this is not yet clear, but by suppressing Al to 60 mass% or less and increasing Fe to 40 mass% or more, (1) destabilizing the Al oxide formed during hot stamping. The surface is likely to be etched during the phosphoric acid conversion treatment, which is generally acidic. (2) Further, Si, Mn, and Cr in the plating act as crystal nuclei of the phosphoric acid conversion crystal, resulting in dense phosphorylation. It is speculated that the formation of a crystalline film has an effect on each.
[0057]
　The second role of the Fe-Al based plating layer is to improve the possibility of corrosion resistance after coating. As described above, since the Al oxide is formed on the Fe-Al-based plating layer, the reactivity with the treatment solution of the phosphoric acid conversion treatment is hindered and the adhesion of the electrodeposition coating film after the electrodeposition coating treatment is improved. And the corrosion resistance after coating may decrease. More specifically, the possibility of post-painting corrosion resistance means that after hot stamping, a phosphoric acid conversion treatment and an electrodeposition coating treatment are performed, and a cutter imparts a flaw to the coating film (a flaw due to chipping or the like is simulated. It is possible that the corrosion swelling (Blister) of the coating film from the flaw portion is likely to spread if it is corroded after this.
[0058]
　As a result of diligent studies on the above possibility, the inventors of the present application have found that the spread of corrosion swelling of the coating film from the flaw is caused by the decrease in the reactivity of the phosphorylation conversion treatment and the corrosion of the Fe—Al-based plating layer. I found that. Further, the inventors of the present application, in order to suppress such a cause, similarly to the possibility of corrosion resistance of the molded portion, the composition of the Fe—Al based plating layer is set to Al: 60 mass% or less, Fe: 40 mass% or more, In addition to improving the reactivity of the phosphoric acid conversion treatment by containing Si, Mn, and Cr, controlling the composition of the A layer, B layer, C layer, and D layer to the above composition. It was found that it is important to suppress the corrosion of the Fe-Al based plating layer.
[0059]
　The compositions of the A layer, the B layer, the C layer, and the D layer here are specifically as described above. The composition of the A layer and the C layer is, in mass %, Al: 40% or more and 60% or less, Fe: 40% or more and less than 60%, Si: 5% or less (not including 0%), Mn: 0.5. % (Not including 0%) and Cr: less than 0.4% by mass (not including 0% by mass). The composition of the B layer is, in mass %, Al: 20% or more and less than 40%, Fe: 50% or more and less than 80%, Si: more than 5% and 15% or less, Mn: 0.5% or more and 10% or less, Cr: It is 0.4 mass% or more and 4 mass% or less. The composition of the D layer is% by mass, Al: less than 20% (not including 0%), Fe: 60% or more and less than 100%, Si: 5% or less (not including 0%), Mn:0. 0.5% to 2%, Cr: 0.4% to 4% by mass.
[0060]
　The reason why the composition of the A layer, B layer, C layer, and D layer as described above suppresses the corrosion of the Fe—Al-based plating layer is not yet clear, but is estimated as follows. There is. That is, the A layer and the C layer on the surface side of the D layer relatively corrode first, and further, the corrosion products of the A layer and the C layer act as a barrier layer against the subsequent progress of corrosion. However, it is presumed that it suppresses corrosion swelling of the coating film on the flaw. In particular, it is considered that a sufficient content of Al and suppression of excessive content of Fe, Si, and Mn act as a barrier layer that suppresses the progress of corrosion most. As such a specific composition, considering that the reactivity of the phosphorylation as described above is also satisfied at the same time, the composition of the A layer and the C layer is, in mass %, Al: 40% or more and 60% or less, Fe: 40% or more and less than 60%, Si: 5% or less (not including 0%), Mn: less than 0.5% (not including 0%), Cr: less than 0.4 mass% (0 mass) % Is not included).
[0061]
　On the other hand, with respect to the above-described corrosion of the A layer and the C layer, the B layer and the D layer having a small Al content become electrochemically noble and are less likely to corrode than the A layer and the C layer. Further, although the B layer and the D layer are not located on the outermost surface, the B layer and the D layer may be exposed as a result of cracking in plating at the molding crack portion. Therefore, it was found that the phosphoric acid conversion treatment property is important from the viewpoint of corrosion resistance, and it is important to sufficiently contain Fe, Si and Mn from the viewpoint of easy formation of such phosphoric acid conversion crystals.
[0062]
　In consideration of simultaneously satisfying the reactivity of phosphorylation as described above as such a specific composition, the composition of the D layer is, by mass %, Al: less than 20% (0% is not included). ), Fe: 60% or more and less than 100%, Si: 5% or less (not including 0%), Mn: 0.5% or more and 2% or less, Cr: 0.4% by mass or more and 4% by mass or less. .. Further, since the B layer is sandwiched between the A layer and the C layer, it has a composition of Al and Fe close to those of the A layer and the C layer, and further contains Si and Mn to protect the Si and Mn from the oxide. This suppresses corrosion of the B layer. As a specific composition thereof, considering that the reactivity of the above-mentioned phosphorylation is also satisfied at the same time, the composition of the B layer is, by mass %, Al: 20% or more and less than 40%, Fe: 50% or more and 80%. %, Si: more than 5% and 15% or less, Mn: 0.5% or more and 10% or less, Cr: 0.4% by mass or more and 4% by mass or less.
[0063]
　As described above, (1) in order to improve the corrosion resistance of the formed part, to improve the chemical conversion treatment of cracks in the Fe—Al based plating layer, and (2) in order to improve the corrosion resistance after coating, the Fe—Al based By providing the B layer and the D layer, which are relatively hard to corrode, and the A layer and the C layer, which are likely to corrode but are expected to improve the corrosion resistance by the generated corrosion product, in the plating layer, the technique according to the present embodiment Was completed.
[0064]
[Regarding Number Density of Kirkendall Voids ] Further
　, in the D layer, Kirkendall voids having an area (cross-sectional area) of 3 μm 2 or more and 30 μm 2 or less are provided as a number density of 10 pieces/6000 μm 2 or more 40 Pcs/6000 μm 2 or less. Thereby, the corrosion resistance of the molded part is more surely improved. The presence of Kirkendall voids in the D layer relieves stress concentration on plating during hot stamping and suppresses peeling of the plating, resulting in improved corrosion resistance of the formed part. Such an effect cannot be obtained when the number density of Kirkendall voids is less than 10 pieces/6000 μm 2 . On the other hand, if the number density of Kirkendall voids exceeds 40/6000 μm 2 , it will rather be the starting point of plating separation during hot stamping.
[0065]
　The number density of Kirkendall voids is controlled as follows. That is, since the formation of Kirkendall voids is caused by the diffusion of Al and Fe, the number density of Kirkendall voids increases due to the increase in the maximum attainable plate temperature and the heating time of the steel plate during hot stamping. Further, during heating at the time of hot stamping in which an alloying reaction occurs due to diffusion of Fe into the plating, dY/dX, which will be described later, which is a gradient in the change with time of the heating rate, becomes 0, and thus Kirkendal The number density of voids can be controlled to a desired value.
[0066]
　As a method of specifying the area (cross-sectional area) of the Kirkendall voids mentioned here, four layers of A layer, B layer, C layer, and D layer are obtained by the method using the scanning electron microscope (SEM) described above. To identify and distinguish each. After that, the same field of view was photographed with a composition image with a magnification of 1000 times (referred to as a backscattered electron beam image), and in the obtained composition image, a black contrast portion existing inside the D layer was identified as Kirkendall void. can do. Kirkendall voids are dented due to holes in the plating, and the reflected electron beam is difficult to detect from the dents due to steric hindrance, so that black is observed as a contrast in the composition image. At this time, the longest diameter and the shortest diameter when the black-observed grain is surrounded by an ellipse are measured, and half of the average value of the obtained long diameter and the shortest diameter is treated as a radius r, which is given by πr 2. The value is the size of the Kirkendall void area (cross-sectional area). Most of the Kirkendall voids have a circular or elliptical shape, but in some cases, a plurality of Kirkendall voids may come into contact with each other during the growth process and become amorphous. In that case, the major axis and the minor axis are defined as the longest diameter of the smallest circumscribed circle that circumscribes an indeterminate Kirkendall void, and the largest inscribed circle that inscribes an indeterminate Kirkendall void. Use a short diameter.
[0067]
　Further, in an observation field of view of 1000 times, the Fe—Al based plating layer was surrounded by a rectangle having a thickness of 60 μm and a length of 100 μm, and the result of counting the number of Kirkendall voids in the D layer included in the region was calculated. The number density of Kendal voids (number/6000 μm 2 ) is used. FIG. 5 shows an example of determining the number density of Kirkendall voids contained in the D layer in the examples described below.
[0068]
[Regarding Oxide Layer]
　Further, it is preferable that the surface of the A layer further has an oxide layer selectively made of an oxide of Mg and/or Ca with a thickness of 0.1 μm or more and 3 μm. And more preferable from the viewpoint of improving the corrosion resistance after painting. By forming an oxide layer composed of an oxide of Mg and/or Ca on the surface of the A layer, lubricity at the time of hot stamping is improved, damage of plating is suppressed, and a chemical conversion film is formed. Since the formation of the is promoted, the corrosion resistance of the molded part and the corrosion resistance after coating are improved. When the thickness of the oxide layer is less than 0.1 μm, the above effects cannot be obtained, and when the thickness of the oxide layer exceeds 3 μm, the adhesion of the oxide layer decreases. It causes peeling of the electrodeposition coating film formed later.
[0069]
　The oxide layer composed of an oxide of Mg and/or Ca mentioned here is a layer that is distinguished from the A layer, and is a layer that contains Mg and Ca in a total amount of 10% by mass or more. In addition, in the A layer, the total content of Mg and Ca is less than 10% by mass. As a method for specifying the thickness and composition of the oxide layer made of an oxide of Mg and/or Ca, the obtained cross section is observed by EPMA without performing etching after polishing the cross section of the plating, as described above. Then, the elemental analysis is continuously performed on a line perpendicular to the surface, and the thickness is determined from the total Mg and/or Ca content of 10% by mass or more.
[0070]
[Other coating layers that the hot stamp member can have]
　Regarding the Fe—Al based hot stamp member according to the present embodiment, the base material and the Fe—Al based plating layer are as described above. When the member is used as an automobile part, it is later subjected to various treatments such as welding, chemical conversion treatment, and electrodeposition coating to be a final product.
[0071]
　The chemical conversion treatment is usually a phosphoric acid conversion treatment (chemical conversion treatment containing phosphorus and zinc as a main component) or a zirconium-based chemical conversion treatment (chemical conversion treatment containing zirconium as a main component). Further, a chemical conversion treatment film accompanying these chemical conversion treatments is formed on the surface of the member. In addition, as electrodeposition coating, usually, cationic electrodeposition coating (C is the main component) is often applied to a film thickness of about 1 to 50 μm. After electrodeposition coating, intermediate coating, top coating, etc. May be painted. The coating layer formed by these treatments and the A layer, B layer, C layer, and D layer of the Fe—Al-based plating layer can be easily identified and distinguished from each other by the difference in the main component. A layer containing 40% by mass or more is defined as a Fe—Al based plating layer.
[0072]
　The Fe—Al based plated hot stamp member according to this embodiment has been described above in detail.
[0073]

　Next, a manufacturing method of the Fe—Al based hot stamping member according to the present embodiment will be described.
[0074]
　In the method for manufacturing the Fe—Al-based plated hot stamp member according to the present embodiment, the chemical composition is adjusted in the steel making process so as to satisfy the above-described chemical composition, and the slab (base metal ) Is produced, and then the obtained slab (base material) is hot-rolled, pickled and cold-rolled to obtain a cold-rolled steel sheet. Recrystallization annealing, hot dip aluminum plating treatment to make Al-based plated steel sheet continuously, after blanking the obtained Al-plated steel sheet, by continuously heating, forming and quenching in hot stamping equipment, The Fe—Al based plated hot stamp member according to the embodiment is manufactured. Hereinafter, a method for manufacturing the Fe—Al-based plated hot stamp member according to this embodiment will be described in detail.
[0075]
(Manufacture of Al-plated steel sheet) In the
　present embodiment, the hot rolling is not particularly limited with respect to the steps until the Al-plated steel sheet is obtained. For example, hot rolling is started at a heating temperature of 1300° C. or lower (for example, within the range of 1000 to 1300° C.), and hot rolling is completed at around 900° C. (for example, within the range of 850 to 950° C.), and rolling is performed. The rate may be in the range of 60 to 90%.
[0076]
　The coiling temperature of the steel sheet after hot rolling as described above is not particularly limited, and may be, for example, in the range of 700° C. or higher and 850° C. or lower.
[0077]
　The conditions for pickling the steel sheet after hot rolling are not particularly limited, and may be hydrochloric acid pickling or sulfuric acid pickling, for example.
[0078]
　Furthermore, the conditions of the cold rolling performed after the above pickling are not particularly limited, and for example, the rolling ratio can be appropriately selected within the range of 30 to 90%.
[0079]
　After the cold-rolled steel sheet is obtained by the steps as described above, the obtained cold-rolled steel sheet is continuously subjected to recrystallization annealing and hot dip aluminum plating in a hot dip coating line to obtain an Al-plated steel sheet. In the present embodiment, the hot dip aluminum plating is performed by immersing the hot dip aluminum plating bath and controlling the amount of the hard aluminum plating applied by a wiping process. The composition of the hot-dip aluminization bath contains, by mass%, Al: 80% or more and 96% or less, Si: 3% or more and 15% or less, Fe: 1% or more and 5% or less so that the total is 100% or less. However, the balance is impurities.
[0080]
　Al is an element necessary for improving the oxidation resistance and the corrosion resistance during heating of the hot stamp, and when the Al content is less than 80% by mass, the corrosion resistance of the plating is poor and the Al content is If it exceeds 96% by mass, the plating tends to peel off during the molding of the hot stamp, resulting in poor corrosion resistance. The content of Al in the molten aluminum plating bath is preferably 82% by mass or more. The content of Al in the molten aluminum plating bath is preferably 94% by mass or less.
[0081]
　Si is an element necessary for improving the corrosion resistance of the Fe-Al-based plating after hot stamping. If the Si content is less than 3% by mass, the corrosion resistance of the plating is poor and the Si content is low. When it exceeds 15% by mass, non-plating occurs after the hot dipping treatment. The content of Si in the molten aluminum plating bath is preferably 5% by mass or more. The content of Si in the molten aluminum plating bath is preferably 12% by mass or less.
[0082]
　Fe in the hot dip aluminum plating bath is inevitably contained due to the elution of Fe when the steel sheet is immersed, but it is an element necessary for promoting the Fe content of the Fe—Al-based plating. When the Fe content is less than 1% by mass, the corrosion resistance of the plating is poor, and when the Fe content exceeds 5% by mass, a large amount of dross is formed in the molten aluminum plating bath. As a result, it becomes a flaw during press molding and impairs the appearance quality. The content of Fe in the molten aluminum plating bath is preferably 2% by mass or more. The content of Fe in the molten aluminum plating bath is preferably 4% by mass or less.
[0083]
　Further, it is preferable that the total amount of Mg and/or Ca contained in the molten aluminum plating bath is 0.02% by mass or more and 3% by mass or less from the viewpoint of improving the corrosion resistance of the Fe—Al based plating. When the total content of Mg and Ca is less than 0.02% by mass, the effect of improving corrosion resistance cannot be obtained. On the other hand, when the total content of Mg and Ca exceeds 3% by mass, the excessive oxide generated causes a problem of non-plating during the hot dipping treatment. The total content of Mg and Ca in the molten aluminum plating bath is preferably 0.05% by mass or more and 2% by mass or less. The total content of Mg and Ca in the molten aluminum plating bath is more preferably 0.1% by mass or more. Further, the total content of Mg and Ca in the molten aluminum plating bath is more preferably 1% by mass or less.
[0084]
　By adding Mg and/or Ca in a total amount of 0.02% by mass or more and 3% by mass or less to the molten aluminum plating bath, Mg and/or Ca in the plating layer before hot stamping in a total of 0. It becomes possible to make it contain 02 mass% or more and 3 mass% or less. Since Mg and Ca are very easily oxidizable elements, after hot stamping, Mg and/or Ca forms an oxide film on the surface of the A layer of the Fe—Al based plating layer, and during the Fe—Al based plating. Hardly survives. Further, the oxide film thus formed becomes the oxide layer made of the oxide of Mg and/or Ca described above.
[0085]
　The thickness of the oxide film formed after hot stamping can be controlled as follows. That is, the Mg and/or Ca oxide film is formed by the Mg and/or Ca contained in the hot dip bath being diffused and oxidized by the heating during hot stamping. Therefore, the film thickness of the oxide film after hot stamping can be increased by increasing the contents of Mg and Ca in the plating bath. Further, the longer the heating time during hot stamping and the higher the maximum reached plate temperature, the more the thickness of the oxide film after hot stamping can be increased. However, depending on the contents of Mg and Ca in the hot dipping bath. Therefore, the increase rate tends to be saturated.
[0086]
　The conditions of the above wiping treatment are not particularly limited, but an aluminum-based plating layer is formed by controlling the adhesion amount of aluminum plating to 30 g/m 2 or more and 120 g/m 2 or less per side. Is preferred. When the adhesion amount of the aluminum plating is less than 30 g/m 2 per side , the corrosion resistance after hot stamping may be insufficient. On the other hand, when the adhesion amount of the aluminum plating exceeds 120 g/m 2 on one side, there may be a problem that the plating is peeled off during hot stamping. The amount of aluminum plating deposited on one surface is more preferably 40 g/m 2 or more. Further, the amount of aluminum plating adhered to one surface is more preferably 100 g/m 2 or less.
[0087]
　Examples of the method for specifying the amount of aluminum plating adhered include the sodium hydroxide-hexamethylenetetramine/hydrochloric acid stripping weight method. Specifically, as described in JIS G 3314:2011, a test piece having a predetermined area S(m 2 ) (for example, 50 mm×50 mm) is prepared and the weight w 1 (g) is measured. After that, it is sequentially dipped in an aqueous solution of sodium hydroxide and an aqueous solution of hydrochloric acid to which hexamethylenetetramyin has been added until foaming stops, then immediately washed with water, and the weight w 2 (g) is measured again . At this time, the adhesion amount (g/m 2 ) of the aluminum plating on both surfaces of the test piece can be calculated from (w 1 -w 2 )/S.
[0088]
(Production of Hot Stamping Member) The
　steel sheet having aluminum plating adhered thereto (Al-plated steel sheet) obtained as described above is blanked, and then continuously heated, molded and rapidly cooled in a hot stamping facility. As a result, during heating, Fe diffuses to the surface of the aluminum plating, and a Fe—Al based plated high strength hot stamp member is manufactured. Here, the heating method is not particularly limited, and it is possible to use furnace heating using radiant heat, near-infrared method, far-infrared method, induction heating or electric heating. is there.
[0089]
　Here, when manufacturing the hot stamp member according to the present embodiment, the time from the charging of the Al-plated steel sheet after blanking to the heating equipment such as the heating furnace to the removal thereof is referred to as heating time. I will. It should be noted that the heating time does not include the transportation time after the Al-plated steel sheet is taken out from the heating equipment or the hot forming time as described below. In the present embodiment, the heating time is controlled to be 150 seconds or more and 650 seconds or less. When the heating time from putting the Al-plated steel sheet after blanking into the heating equipment to taking it out is less than 150 seconds, the diffusion of Fe into the Al plating is insufficient and soft Al remains. However, it is not preferable because the corrosion resistance of the molded product and the corrosion resistance after coating are poor. On the other hand, when the heating time exceeds 650 seconds, Fe is excessively diffused during Al plating, the four-layer structure cannot be maintained, and corrosion due to Fe becomes remarkable, which is not preferable. .. The heating time from when the blanked Al-plated steel sheet is put into the heating equipment to when it is taken out is preferably 200 seconds or more, more preferably 250 seconds or more. The heating time from the time the blanked Al-plated steel sheet is put into the heating equipment to the time it is taken out is preferably 600 seconds or less, more preferably 550 seconds or less.
[0090]
　In addition, in the above heating step, the maximum reached plate temperature of the Al-plated steel plate is set to 850°C or higher and 1050°C or lower. The reason why the maximum reached plate temperature is set to 850° C. or higher is to heat the steel plate to the Ac1 point or higher to cause martensite transformation at the time of quenching in the die thereafter to increase the strength of the base material and to sufficiently increase the plating surface. This is because Fe is diffused into the alloy to promote alloying of the Al plating layer. The maximum ultimate plate temperature of the Al-plated steel plate is more preferably 910°C or higher. On the other hand, when the maximum reached plate temperature exceeds 1050° C., Fe is excessively diffused into the Fe—Al-based plating, resulting in poor corrosion resistance after coating and corrosion resistance of the formed part. The highest ultimate plate temperature of the Al-plated steel plate is more preferably 980°C or lower.
[0091]
　Then, the heated Al-plated steel sheet is hot stamped into a predetermined shape between a pair of upper and lower molding dies. By holding still for several seconds at the bottom dead center of the press after forming, quenching and quenching the steel plate by contact cooling with the forming die, the hot stamp formed high-strength member according to the present embodiment. Obtainable. By setting the average cooling rate during quenching to 30° C./second or more, the martensitic transformation is sufficiently advanced and the strength of the base material is increased. In the present embodiment, as described above, the Vickers hardness (load 9.8N) of the base material becomes 300 HV or more by the quenching by such quenching. The upper limit of the average cooling rate during quenching is not particularly limited, and the higher the better, the better, but the upper limit is substantially about 1000° C./second. Here, the average cooling rate (° C./s) is, for example, using a thermocouple or a radiation thermometer, a time t 0 (second) required until the steel plate temperature is rapidly cooled from 800° C. to 200° C. or less is measured. Then, it can be obtained as (800-200)/t 0 from the obtained time t 0 (seconds) .
[0092]
　Here, the steel plate temperature Y (° C.) and the heating time X (second) in heating are controlled so that the heating time X when the steel plate temperature Y is 600° C. or more and 800° C. or less is 100 seconds or more and 300 seconds or less. .. By setting the heating time X and the steel plate temperature Y of the steel plate within the above ranges, the diffusion of Fe during plating is controlled, and the Al-plated steel plate is a hot stamp member excellent in the corrosion resistance of the above-mentioned formed part and the corrosion resistance after coating. Changes to. When the steel sheet temperature Y is lower than 600° C. or higher than 800° C., the corrosion resistance of the formed part and the corrosion resistance after coating are lowered. Also, when the heating time X is less than 100 seconds or more than 300 seconds, the corrosion resistance of the molded part and the corrosion resistance after coating decrease. Regarding heating during hot stamping, the heating time X when the steel plate temperature Y is 600° C. or higher and 800° C. or lower is preferably 120 seconds or more, more preferably 150 seconds or more. The heating time X when the steel plate temperature Y is 600° C. or higher and 800° C. or lower is preferably 280 seconds or less, more preferably 250 seconds or less.
[0093]
　Regarding the steel plate temperature Y in heating, when the first derivative (dY/dX) of the steel plate temperature Y with respect to the heating time X is 0, the steel plate temperature Y exists within the range of 600°C to 800°C. Control. When the first derivative (dY/dX) becomes zero, an extreme value exists when the steel sheet temperature Y changes over time, and exists in the temperature range of 600°C or higher and 800°C or lower, which is important for diffusion of Fe during plating. As a result, the diffusion time of Fe can be controlled more reliably as the heating time becomes longer. Here, regarding the meaning of "more reliable control", the time period between 600°C and 800°C is not important. Changes in the phase structure of plating due to diffusion of elements such as Fe, Al, Si, Mn, and Cr, and eventually the chemical compositions of the A layer, B layer, C layer, and D layer, change from moment to moment. Therefore, in order to control the phase structure and composition, it is most important to realize a state in which the first derivative (dY/dX) becomes zero. As a result, the concentration of Mn and the concentration of Cr in the B layer and the D layer as described above can be realized more reliably. In the case where the first derivative (dY/dX) becomes zero, the above effect is obtained because the steel plate temperature Y exists in the range of 600° C. or higher and 800° C. or lower.
[0094]
　Here, regarding the mechanism by which the composition of the A layer, the B layer, the C layer, and the D layer described above is realized by performing the heat treatment in accordance with the heat treatment conditions described above, there are also unclear points. However, it is presumed that the phenomenon described below has occurred. That is, by performing the heat treatment according to the heat treatment conditions as described above, in addition to Fe, Mn and Cr derived from the steel sheet diffuse into the plating layer. Mn and Cr derived from the steel sheet once diffuse to the surface of the plating layer during the heat treatment, and then the layers A to D are formed. Here, in the process of forming the A layer and the C layer, Mn and Cr, which are elements that are difficult to be contained in the A layer and the C layer, are discharged from the forming A layer and the C layer to the outside of the layer. Then, the layers B and D, which are being formed, are concentrated. Therefore, the contents of Mn and Cr contained in the B layer and the D layer may be higher than the contents of Mn and Cr contained in the steel sheet. Since the above diffusion phenomenon occurs between 600 and 800° C., in order to control the diffusion of elements, it is necessary to control the first derivative (dY/dX) in addition to the heating time of the material at 600 to 800° C. is there. Ultimately, it is presumed that the composition of the layers A to D as described above will be realized at the stage of the Fe—Al based plated hot stamp member which has been heated.
[0095]
　The number of times that the first derivative (dY/dX) becomes 0 in the range where the steel plate temperature Y is 600° C. or higher and 800° C. or lower is not particularly limited. For example, if the temperature is kept constant at 700° C., the number of times the first derivative (dY/dX) becomes 0 is once. As another example, after heating in a 900° C. furnace, the temperature reached 700° C. during the temperature rise, immediately moved to a 600° C. heating furnace, and held until the plate temperature reached 600° C. If the method of heating in a furnace at 0° C. is adopted, the number of times that the first derivative (dY/dX) becomes 0 is 2 times. The number of times the first derivative (dY/dX) becomes 0 is not particularly limited as long as it is 1 or more, but it should be 3 or less because the manufacturing facility becomes complicated and the cost becomes high. Is preferred.
[0096]
　The steel plate temperature Y in heating is determined by spot welding a K-type thermocouple to a 300 mm×300 mm steel plate and measuring the steel plate temperature during heating. The steel plate temperature at this time is sampled at a time interval of 0.1 seconds and digitized. As for the first derivative (dY/dX) of the steel plate temperature Y, when the steel plate temperature is measured at intervals of 0.1 second and the steel plate temperature at a certain point is Y1 and the steel plate temperature 0.1 seconds later is Y2, It can be calculated from (Y2-Y1)/0.1.
[0097]
(Regarding Post-
　Processing after Hot Stamping) The hot stamping member becomes a final part after post-processing such as welding, chemical conversion treatment, and electrodeposition coating. As the chemical conversion treatment, a zinc phosphate-based coating or a zirconium-based coating is usually applied. Further, as the electrodeposition coating, usually, cationic electrodeposition coating is often used, and the film thickness thereof is about 5 to 50 μm. After the electrodeposition coating, a coating such as an intermediate coating or a top coating may be further applied to improve the appearance quality and the corrosion resistance.
[0098]
　Heretofore, the method for manufacturing the Fe—Al based plated hot stamp member according to the present embodiment has been described in detail.
Example
[0099]
　Hereinafter, the Fe—Al-based plated hot stamp member and the method for manufacturing the same according to the present invention will be described more specifically with reference to examples. The examples shown below are merely examples of the Fe—Al based plated hot stamp member and the manufacturing method thereof according to the present invention, and the Fe—Al based hot stamp member according to the present invention and the manufacturing method thereof are the following examples. It is not limited to.
[0100]

　A cold rolled steel sheet (sheet thickness: 1.4 mm) having a steel composition as shown in Table 1 below was used as a test material, and was continuously subjected to recrystallization annealing through a hot rolling step and a cold rolling step. , Hot dip aluminum plating treatment was performed. In Table 1, the mass ratios of Al, Fe, and Si, which have relatively large contents, are rounded off to whole numbers. The coiling temperature during hot rolling is 700° C. or higher and 800° C. or lower. For hot dip Al plating, a non-oxidizing furnace-reducing furnace type line is used. It was adjusted to m 2 or more and 120 g/m 2 or less, and then cooled. The composition of the aluminum plating bath at this time was Al-2% Fe, and Si was 3% or more and 15%. The obtained Al-plated steel sheet was blanked to 240 mm×300 mm, and formed into a hat shape with a bending R=5 mm under the conditions shown in Table 2-1 and Table 2-2 below. A high-strength hot stamp member was obtained by rapidly cooling at a cooling rate of not less than °C/sec and setting the holding time at the bottom dead center to 10 seconds.
[0101]
　Here, heat treatment conditions A to F in Tables 2-1 and 2-2 below are the following conditions, respectively.
[0102]
　　A: dY/dX=0, heating time: 500 seconds, maximum plate temperature: 950° C., heating time between 600° C. and 800° C. X: 200 seconds
　　B: dY/dX≠0 (monotonic increase) Temperature), heating time: 500 seconds, maximum reaching plate temperature: 950° C., heating time at 600° C. or higher and 800° C. or lower X: 60 seconds
　　C: dY/dX≠0 (monotonous temperature rise), heating time: 300 seconds, Maximum reaching plate temperature: 850° C., 600° C. or more and 800° C. or less Heating time X: 150 seconds
　　D: dY/dX≠0 (monotonic temperature increase), heating time: 100 seconds, maximum reaching plate temperature: 700° C., 600 Heating time in the range from ℃ to 800°C X: 30 seconds
　　E: dY/dX=0, heating time: 700 seconds, maximum reaching plate temperature: 1100°C, heating time X in the range from 600°C to 800°C : 400 seconds
　　F: dY/dX=0, heating time: 300 seconds, maximum temperature reached: 650° C., heating time between 600° C. and 800° C. X: 100 seconds
[0103]
　In addition, a K-type thermocouple was spot-welded to the Al-plated steel sheet blanked in advance to 240 mm×300 mm, and the steel sheet temperature during heating was measured. As a result of actually measuring the steel plate temperature Y during hot stamp heating, the heating time X when the steel plate temperature Y is 600° C. or higher and 800° C. or lower is as shown in Tables 2-1 and 2-2 below.
[0104]
　Regarding the hot stamp member manufactured by using the base material shown in Table 1 below under various conditions, the thickness of the Fe—Al based plating layer and the composition of the A layer, the B layer, the C layer, and the D layer were determined. It was specified by analyzing with EPMA according to the method described above. In addition, the number of Kirkendall voids having a cross-sectional area of ​​3 μm 2 or more and 30 μm 2 or less was measured in the D layer according to the method described above. As a specific example of the hot stamp member corresponding to the invention example, FIGS. 2, 3 and 4 show the results obtained by analyzing the points marked with “+” from the sectional image shown in FIG. The respective compositions of the A layer, B layer, C layer and D layer are shown in Table 2-1 below. In addition, No. shown in Table 2-2. The samples of Nos. 20 to 22 did not have the four-layer structure of the A layer, the B layer, the C layer, and the D layer as noted in the present invention, and therefore the detailed composition of each layer was not specified.
[0105]
　Further, each hot stamp member was evaluated for corrosion resistance in the molded part and corrosion resistance after coating according to the following criteria.
[0106]
　The molded part corrosion resistance was evaluated by the following procedure.
　Each of the hot stamped members having a bending R=5 mm, which is a hot stamp member manufactured by the above procedure, was subjected to a chemical conversion treatment using a chemical conversion treatment liquid PB-SX35T manufactured by Nippon Parkerizing Co., Ltd. ) Cationic electrodeposition paint Powernics 110 of about 10 μm thickness was applied. After that, a composite corrosion test (JASO M610-92) defined by the Society of Automotive Engineers of Japan was carried out for 60 cycles (20 days), and it was confirmed whether red rust occurred in the R part of the molded product. If there is red rust in the molded product, the rating is “VB (Very Bad)”. Similarly, if there is red rust at the stage of 120 cycles (40 days), the rating is “B (Bad)”, and there is red rust. When there was not, it was set as the rating "G (Good)". "G" was taken as a pass level, and "B" and "VB" were taken as fail levels.
[0107]
　The corrosion resistance after painting was evaluated by the following procedure.
　Similarly, each of the manufactured hat molded products was subjected to a chemical conversion treatment with a chemical conversion treatment liquid PB-SX35T manufactured by Nippon Parkerizing Co., Ltd., and then a cationic electrodeposition paint Powernics 110 manufactured by Nippon Paint Co., Ltd. was about 10 μm. Painted with thickness. After that, a vertical cross section of the molded product is cross-cut with a cutter, and a composite corrosion test (JASO M610-92) defined by the Society of Automotive Engineers of Japan is performed for 180 cycles (60 days), and the cross-cut coating film The swollen width was measured. At this time, as a comparative material, an alloyed hot-dip galvanized steel sheet (GA: adhesion amount 45 g/m 2 on one side ) was used, and the same chemical conversion treatment, electrodeposition coating, and cross cut as above were tested. When the swelling width of the coating film is greater than GA, the rating is "B (Bad)", and when the swelling width of the coating film is less than GA, the rating is "G (Good)". The case where it was less than 1/2 of GA was rated as "VG (Very Good)". “G” and “VG” were taken as pass levels, and “B” was taken as a fail level.
[0108]
　The evaluation results relating to the corrosion resistance of the molded part and the corrosion resistance after coating according to the above criteria are summarized in Tables 2-1 and 2-2 below. In addition, No. shown in Table 2-2. 20-No. For the sample No. 22, the number of Fe-Al based plating layers was out of the range of the present invention, so the detailed composition of the Fe-Al based plating layer was not measured and the obtained sample was evaluated. I didn't.
[0109]
[table 1]

[0110]
[Table 2-1]

[0111]
[Table 2-2]

[0112]
　As is apparent from Table 2-1 above, No. 1 corresponding to the invention example of the present application. 1 to No. The sample of No. 16 corresponds to the comparative example. 17-No. As compared with the sample of No. 19, it can be seen that both the corrosion resistance of the molded part and the corrosion resistance after coating are excellent.
[0113]
When
　obtaining a hot stamp member by the same manufacturing method as in Example 1, 0.02 mass% or more and 2 mass% or less of Mg or Ca is further added as a plating bath composition to obtain a hot stamp member. The results are shown in Table 3 below. Here, as the heat treatment condition, the condition “A” in Example 1 was adopted. In addition, the results of examining the thickness of the oxide layer made of an oxide of Mg or Ca by a cross-sectional SEM are also shown in Table 3 below. The evaluation criteria for the corrosion resistance of the molded part and the corrosion resistance after coating are the same as in Example 1.
[0114]
[Table 3]

[0115]
　As is clear from Table 3 above, No. 1 corresponding to the invention example of Table 3 has a preferable thickness of the oxide layer formed of an oxide of Mg or Ca of 0.1 μm or more and 3 μm or less. 31-No. The sample of No. 33 is No. 33 in Table 2-1. It can be seen that both the corrosion resistance of the molded part and the corrosion resistance after coating are superior to the sample of No. 10.
[0116]
As in
　Example 1, cold-rolled steel sheets (sheet thickness: 1.4 mm) having the steel components shown in Table 1 were used as test materials, and were continuously subjected to a hot rolling step and a cold rolling step. Recrystallization annealing and hot dip aluminum plating were performed. The coiling temperature during hot rolling is 700° C. or higher and 800° C. or lower. For hot dip Al plating, a non-oxidizing furnace-reducing furnace type line is used. It was adjusted to m 2 or more and 120 g/m 2 or less, and then cooled. The plating bath composition at this time is shown in Table 4 below.
[0117]
　The obtained Al-plated steel sheet was blanked to 240 mm×300 mm, heated, and then heated under the conditions shown as the heat treatment condition A of Example 1 for hot stamping, formed into a hat mold, and heated at 50° C./ A high-strength hot stamp member was obtained by quenching at a cooling rate of at least 2 seconds and setting the holding time at bottom dead center to 10 seconds.
[0118]
　In addition, a K-type thermocouple was spot-welded to the Al-plated steel sheet blanked in advance to 240 mm×300 mm, and the steel sheet temperature during heating was measured. The heating time X was measured when the steel plate temperature Y during hot stamping heating was 600° C. or higher and 800° C. or lower. Detailed manufacturing conditions are shown in Table 6 below.
[0119]
　With respect to the hot stamp member thus manufactured, the corrosion resistance after molding and the corrosion resistance after coating were evaluated according to the same criteria as in Example 1, and the obtained results are also shown in Table 4 below.
[0120]
[Table 4]

[0121]
　As is apparent from Table 4 above, No. 1 corresponding to the invention example of the present application. 41-No. The sample of No. 42 corresponds to the comparative example. 43-No. It can be seen that compared with the sample of No. 44, the corrosion resistance of the molded part and the corrosion resistance after coating are excellent.
[0122]
　The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.
Industrial availability
[0123]
　According to the present invention, it is possible to provide an Fe—Al-based plated high-strength hot stamp member having excellent corrosion resistance after coating and a method for manufacturing the same, and to improve automobile collision safety and fuel consumption by reducing automobile weight and CO 2 It leads to reduction of exhaust gas.
The scope of the claims
[Claim 1]
　The base material has an Fe-Al based plating layer located on one side or both sides of the base material, and the
　base material is, in mass %,
　　C: 0.1% or more and 0.5% or less
　　Si: 0.01% or more. 2.00% or less
　　Mn: 0.3% or more and 5.0% or less
　　P: 0.001% or more and 0.100% or less
　　S: 0.0001% or more and 0.100% or less
　　Al: 0.01% or more 0. 50% or less
　　Cr: 0.01% or more and 2.00% or less
　　B: 0.0002% or more and 0.0100% or less
　　N: 0.001% or more and 0.010% or less
, and the balance from Fe and impurities The
　Fe—Al-based plating layer has a thickness of 10 μm or more and 60 μm or less, and is composed of four layers of A layer, B layer, C layer, and D layer in order from the surface toward the base material. And
　each of the four layers contains the following components in a total amount of 100% by mass or less, and the balance is an Fe-Al intermetallic compound that is an impurity. area of 3 [mu] m 2 or more 30 [mu] m 2 of Kirkendall voids is less than (Kirkendall void), 10 pieces / 6000 .mu.m 2 or 40/6000 .mu.m Fe-Al based hot stamping member containing 2 or less.
　A layer and C layer
　　Al: 40 mass% or more and 60 mass% or less
　　Fe: 40 mass% or more and less than 60 mass%
　　Si: 5 mass% or less (not including 0 mass%)
　　Mn: less than 0.5 mass% (0 not including
　　mass%). Cr: less than 0.4 wt% (not including 0 mass%).
　B layer
　　Al: less than 20 wt% to 40 wt%
　　Fe: less than 50% by weight to 80% by weight
　　Si: 5 weight % Over 15 mass% or less
　　Mn: 0.5 mass% or more and 10 mass% or less
　　Cr: 0.4 mass% or more and 4 mass% or less
　D layer
　　Al: less than 20 mass% (excluding 0 mass%)
　　Fe: 60 Mass% or more and less than 100 mass%
　　Si: 5 mass% or less (0 mass% is not included)
　　Mn: 0.5 mass% or more and 2.0 mass% or less
　　Cr: 0.4 mass% or more and 4 mass% or less
[Claim 2]
　The Fe-Al-based hot stamping member according to claim 1, further comprising an oxide layer having a thickness of 0.1 μm or more and 3 μm or less, which is made of an oxide of Mg and/or Ca, on the surface of the A layer.
[Claim 3]
　The base material is, in place of a part of the balance of Fe, in mass %,
　　W: 0.01 to 3.00%
　　Mo: 0.01 to 3.00%
　　V: 0.01 to 2.00%
　　Ti : 0.005 to 0.500%
　　Nb: 0.01 to 1.00%
　　Ni: 0.01 to 5.00%
　　Cu: 0.01 to 3.00%
　　Co: 0.01 to 3.00%
　　Sn : 0.005-0.300%
　　Sb: 0.005-0.100%
　　Ca: 0.0001-0.01%
　　Mg: 0.0001-0.01%
　　Zr: 0.0001-0.01%
　　REM
The Fe—Al based plated hot stamp member according to claim 1 or 2, further containing at least any one of 0.0001 to 0.01% .
[Claim 4]
　In mass %,
　　C: 0.1% or more and 0.5% or less
　　Si: 0.01% or more and 2.00% or less
　　Mn: 0.3% or more and 5.0% or less
　　P: 0.001% or more and 0.100 %
　　Or less S: 0.0001% or more and 0.100% or less
　　Al: 0.01% or more and 0.50% or less
　　Cr: 0.01% or more and 2.00% or less
　　B: 0.0002% or more and 0.0100% or less
　　N:
A slab of steel containing 0.001% or more and 0.010% or less and the remainder having a base material component composed of Fe and impurities is hot-rolled, pickled, cold-rolled, and then annealed. After blanking a steel sheet that has been continuously subjected to hot dip aluminum plating, the heating time from the time when the steel sheet after blanking is put into the heating equipment to the time it is taken out is 150 seconds or more and 650 seconds or less, and the steel sheet after the blanking is performed.
　Is heated at 850° C. or higher and 1050° C. or lower, immediately after that, formed into a desired shape and rapidly cooled at a cooling rate of 30° C./second or higher. The composition of the molten aluminum plating bath used for the molten aluminum plating is
　　Al: 80% by mass or more and 96% by mass or less
　　Si: 3% by mass or more and 15% by mass or less
　　Fe: 1% by mass or more and 5%
by mass or less are contained so that the total is 100% by mass or less, and the balance is composed of impurities,
　Regarding the steel plate temperature Y (° C.) and the heating time X (seconds) in the heating, the heating time X when Y is 600° C. or more and 800° C. or less is 100 seconds or more and 300 seconds or less, and Y is A method for producing an Fe-Al-based hot stamping member, wherein Y is present in the range of 600° C. or higher and 800° C. or lower when the first derivative (dY/dX) of X is 0.
[Claim 5]
　The Fe-Al-based hot stamping member according to claim 4, wherein the composition of the molten aluminum plating bath further contains at least either Mg or Ca in a total amount of 0.02% by mass or more and 3% by mass or less. Production method.
[Claim 6]
　The slab, as a base material component, is replaced by a part of the balance of Fe, and in mass %,
　　W: 0.01 to 3.00%
　　Mo: 0.01 to 3.00%
　　V: 0.01 to 2 0.00%
　　Ti: 0.005 to 0.500%
　　Nb: 0.01 to 1.00%
　　Ni: 0.01 to 5.00%
　　Cu: 0.01 to 3.00%
　　Co: 0.01 to 3 0.00%
　　Sn: 0.005 to 0.300%
　　Sb: 0.005 to 0.100%
　　Ca: 0.0001 to 0.01%
　　Mg: 0.0001 to 0.01%
　　Zr: 0.0001 to 0
　　0.01 % REM:
The manufacturing method of the Fe—Al based hot stamping member according to claim 4 or 5, further containing at least one of 0.0001 to 0.01% .