The present invention relates to an aluminum-plated steel sheet, a hot stamping member, and a method for manufacturing a hot stamping member.
　The present application claims priority based on Japanese Patent Application No. 2018-225421 filed in Japan on November 30, 2018, the contents of which are incorporated herein by reference.
Background technology
[0002]
　In recent years, there has been an increasing demand for curbing the consumption of chemical fuels in order to protect the environment and prevent global warming, and this demand is affecting various manufacturing industries. For example, automobiles, which are indispensable for daily life and activities as a means of transportation, are no exception, and improvement of fuel efficiency by reducing the weight of the vehicle body is required. However, in automobiles, simply reducing the weight of the vehicle body may lead to a decrease in safety, and thus is not allowed in terms of product quality. Therefore, when reducing the weight of the vehicle body, it is necessary to ensure appropriate safety.
[0003]
　Most automobile structures are made of iron, especially steel plates, and reducing the weight of the steel plates is important for reducing the weight of the vehicle body. Further, such a request for a steel sheet is made not only in the automobile manufacturing industry but also in various manufacturing industries. In response to such a request, if the weight of the steel sheet is simply reduced, it is conceivable to reduce the thickness of the steel sheet. However, reducing the thickness of the steel plate leads to a decrease in the strength of the structure. Therefore, in recent years, research has been conducted on steel sheets that can maintain or increase the mechanical strength of structures composed of steel sheets even if they are thinner than the steel sheets used before, by increasing the mechanical strength of the steel sheets. Development is in progress.
[0004]
　In general, a material having high mechanical strength tends to have a reduced shape freezing property in a molding process such as a bending process. Therefore, when processing into a complicated shape, the processing itself becomes difficult. As one of the means for solving this problem of moldability, there is a so-called "hot stamping method (sometimes also referred to as a hot stamping method, a hot pressing method, a high temperature pressing method, or a die quenching method)". In this hot stamping method, a material to be molded is heated to a high temperature, and a steel sheet softened by heating is pressed to be molded, and then cooled after molding (or almost at the same time as molding). According to this hot stamping method, the material is once heated to a high temperature to be softened, so that the material can be easily pressed. Furthermore, the mechanical strength of the material can be increased by the quenching effect of cooling after molding. Therefore, by this hot stamping method, a molded product having good shape freezing property and high mechanical strength can be obtained.
[0005]
　However, when this hot stamping method is applied to a steel sheet, it is necessary to apply a rust preventive treatment or a metal coating to the surface of the member after processing for a member or the like that requires corrosion resistance. Therefore, a surface cleaning step, a surface treatment step, and the like for the member are required, and the productivity is lowered.
[0006]
　To solve such a problem, Patent Document 1 describes an aluminum-based galvanized steel sheet for hot pressing having an Al-based metal coating containing Al as a main component and Mg and Si on the surface of steel.
　Patent Document 2 defines the composition of the surface of the steel sheet for hot stamping, and describes that the amount of AlN on the surface of the Al—Fe alloy layer on the surface of the steel is 0.01 to 1 g / m 2 . ..
　Patent Document 3 describes a bcc layer having an Al-Fe intermetallic compound layer on the surface of a steel plate, an oxide film on the surface thereof, and Al between the steel plate and the Al-Fe intermetallic compound layer. The automobile member is described, and the oxide film thickness on the surface of the Al—Fe alloy layer after hot stamping is described. In Patent Document 3, by heating an aluminum-plated steel sheet so that the oxide film has a predetermined thickness, an Al—Fe alloy layer is formed up to the surface layer, and coating film defects and adhesion deterioration after electrodeposition coating are prevented. It is described that it suppresses and secures corrosion resistance after painting.
[0007]
　However, the aluminum-based plated steel sheet for hot stamping described in Patent Document 1 does not have sufficient corrosion resistance after painting after hot stamping. Further, Patent Document 1 does not specify the composition and structure of the outermost surface, and the relationship between the composition and structure of the outermost surface and the corrosion resistance after painting has not been clarified.
　In Patent Document 2, by setting the amount of AlN on the surface of the Al—Fe alloy layer within a predetermined range, the corrosion resistance after coating can be improved to some extent, but there is room for further improvement.
　Further, as described in Patent Document 3, even if the structure and thickness of the Al—Fe alloy layer are controlled, the corrosion resistance after painting is not sufficient. This may be due to a decrease in the amount of the chemical conversion agent attached due to a decrease in the reactivity between the oxide film and the chemical conversion agent.
Prior art literature
Patent documents
[0008]
Patent Document 1: Japanese Patent Application Laid-Open No. 2003-034845
Patent Document 2: Japanese Patent Application Laid-Open No. 2011-137210
Patent Document 3: Japanese Patent Application Laid-Open No. 2009-293078
Outline of the invention
Problems to be solved by the invention
[0009]
　As described above, the conventional technique has a problem that sufficient corrosion resistance after painting of the hot stamp member cannot be ensured.
　The present invention has been made in view of such a problem, and can be applied to a hot stamping member which is excellent in paint adhesion, which has a large influence on post-painting corrosion resistance, and is also excellent in post-painting corrosion resistance, particularly after hot stamping. It is an object of the present invention to provide a suitable aluminum-plated steel sheet.
Means to solve problems
[0010]
　When a hot stamp member is used, for example, in an automobile part, a chemical conversion treatment film containing zinc phosphate, which is a base of an electrodeposition coating film, is formed in the manufacturing process of the automobile, and a resin coating is applied on the chemical conversion treatment film. A film (electrodeposition coating film) is formed. In order to improve the adhesion of the resin-based coating film (electrodeposition coating film), which is a paint, the amount of zinc phosphate crystals precipitated in the chemical conversion-treated film containing zinc phosphate, which is the base film of the resin-based coating film, is increased. It is useful to let them. In the chemical conversion treatment step, zinc phosphate crystals are precipitated when the zinc phosphate concentration in the zinc phosphate aqueous solution exceeds the solubility of zinc phosphate. The solubility of zinc phosphate decreases as the pH of the zinc phosphate aqueous solution increases.
　The present inventors have found that the plating layer of the plated steel sheet before hot stamping, which has been subjected to the micronization treatment of the metal structure of the plating layer by spraying particles immediately after plating, is the Group 2 element and the 4th period d-block element in the periodic table. It has been found that the paint adhesion is improved in the hot stamping member after hot stamping by containing a predetermined amount of one or more selected from the group consisting of two or more and controlling the average crystal grain size of the plating surface layer portion. That is, when the plated steel plate is hot stamped, the oxide film layer formed on the surface of the hot stamping member can contain a predetermined amount of the Group 2 element or the 4th period d-block element of the periodic table, and as a result, the hot stamping can be performed. It has been found that the paint adhesion is improved and the corrosion resistance after painting is improved in the members. The reason why the paint adhesion is improved in the hot stamping member is that the oxide of the Group 2 element or the 4th periodic d-block element of the periodic table formed on the surface by the hot stamping is dissolved in water. It is considered that by increasing the pH on the surface, zinc phosphate crystals are likely to be precipitated as described above, and the paint adhesion is improved.
[0011]
　The present invention has been made based on the above findings. The gist of the present invention is as follows.
[1] The aluminum-plated steel sheet according to one aspect of the present invention has a steel sheet and a plating layer formed on the surface of the steel sheet, and the plating layer is Be, Mg, Ca, Sr, Ba, Sc, The plating layer contains one or more A group elements selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and the balance is Al, Fe, and impurities. The thickness t is 10 to 60 μm, and the average crystal grain size is 2 t / 3 or less and 15 μm or less in the thickness range from the outermost surface of the plating layer to a position 2/3 times the thickness t. ..
[2] In the aluminum-plated steel sheet according to the above [1], the chemical composition of the plating layer is mass%, the total content of the group A elements is 0.001 to 30.00%, and Si: 0 to. It may be 20.0%, Fe: 0 to 10.0%, the balance: Al and impurities.
[3] The aluminum-plated steel sheet according to the above [1] or [2] has a total of 0.001% of Sr content, Mg content and Ca content in mass% in the chemical composition of the plating layer. It may be less than, and the total content of the group A elements may be 0.05 to 30.00%.
[4] For the aluminum-plated steel sheet according to any one of the above [1] to [3], the A group element in the plating layer is measured from the outermost surface of the plating layer in the thickness direction using GDS. In this case, the maximum value of the detection intensity of the group A element in the range from the outermost surface of the plating layer to the position of 1/3 times the thickness t is from the position of 2/3 times the thickness t. It may be 2.0 times or more the average value of the detected intensities of the group A elements in the range up to the position of 1 times the thickness t.
[5] The aluminum-plated steel sheet according to any one of the above [1] to [4] has a chemical composition of the steel sheet in mass%, C: 0.1 to 0.4%, Si: 0.01 to. 0.60%, Mn: 0.50 to 3.00%, P: 0.05% or less, S: 0.020% or less, Al: 0.10% or less, Ti: 0.01 to 0.10% , B: 0.0001 to 0.0100%, N: 0.010% or less, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 1.00%, Ni: 0 It may be ~ 2.00%, Nb: 0 to 1.00%, Sn: 0 to 1.00%, Ca: 0 to 0.10%, the balance: Fe and impurities.
[6] In the method for producing a hot stamping member according to another aspect of the present invention, the aluminum-plated steel sheet according to any one of the above [1] to [5] is heated to a temperature range of 850 to 950 ° C. After holding in the area for 2 minutes or more, hot stamping is performed.
[7] The hot stamping member according to another aspect of the present invention is a hot stamping member obtained by hot stamping the aluminum-plated steel sheet according to any one of the above [1] to [5], and has Be on the surface. , Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, one or more group A elements selected from the group, and Al. It has an oxide film layer containing oxygen.
The invention's effect
[0012]
　According to the above aspect of the present invention, it is possible to provide an aluminum-plated steel sheet which is excellent in adhesion to an electrodeposition coating film (paint adhesion) and is suitable for application to a hot stamping member, particularly after hot stamping. Further, it is possible to provide a method for manufacturing a hot stamping member for hot stamping the aluminum-plated steel sheet and a hot stamping member obtained by hot-stamping the aluminum-plated steel sheet. This hot stamp member is excellent in adhesion to the electrodeposition coating film and corrosion resistance after coating.
A brief description of the drawing
[0013]
FIG. 1 is a schematic view showing a method for measuring an average crystal grain size of a plated layer of an aluminum-plated steel sheet according to the present embodiment.
FIG. 2 is an example of the results of measuring the group A elements in the plating layer in the thickness direction from the outermost surface of the plating layer using GDS for the aluminum-plated steel sheet according to the present embodiment.
FIG. 3 is an example of the results of measuring group A elements in the thickness direction from the outermost surface of the oxide film layer using GDS in a hot stamping member obtained by hot stamping an aluminum-plated steel sheet according to the present embodiment. be.
Mode for carrying out the invention
[0014]
　Hereinafter, the aluminum-plated steel sheet (aluminum-plated steel sheet according to the present embodiment) according to a preferred embodiment of the present invention, the hot stamping member according to the present embodiment, and a method for manufacturing them will be described in detail.
[0015]
(Aluminum-plated steel sheet)
　The aluminum-plated steel sheet according to the present embodiment has a steel sheet and a plating layer formed on the surface of the steel sheet, and the plating layer is Be, Mg, Ca, Sr, Ba, Sc, The plating layer contains one or more A group elements selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, and the balance is Al, Fe, and impurities. The thickness t is 10 to 60 μm, and the average crystal grain size is 2 t / 3 (μm) or less and 15 μm in the range from the outermost surface of the plating layer to a position 2/3 times the thickness t (μm). It is as follows. The crystal grains can be confirmed by etching with a 3% alcohol nitrate solution (Nital solution) to reveal grain boundaries.
[0016]
　In the aluminum-plated steel sheet (aluminum-plated steel sheet) according to the present embodiment, the average crystal grain size of the plating layer is controlled to be small, and the crystal grain boundaries are large. As a result, the area of ​​the interface with the atmospheric gas such as the atmosphere becomes large during the subsequent heating of the hot stamp. Since the group A element has a high affinity with the atmospheric gas, the group A element is concentrated on the surface layer during heating, and the group A element in the oxide film layer formed on the surface layer portion of the member after hot stamping (hot stamping member). The ratio of
[0017]
　In the hot stamping member, the group A element is mainly contained in the oxide film layer in the form of an oxide. When the outermost surface (surface of the oxide film layer) of such a hot stamp member is subjected to chemical conversion treatment, the oxide of the group A element is present on the outermost surface of the hot stamp member to form an oxide film layer. The pH of the chemical conversion treatment liquid at the interface with the treatment liquid rises. As a result, the amount of zinc phosphate crystals precipitated increases. That is, so-called chemical conversion processability is enhanced. Further, by increasing the amount of zinc phosphate crystals precipitated, the adhesion (paint adhesion) of the electrodeposition coating film to be electrodeposited after the chemical conversion treatment is improved. Further, by increasing the adhesion of the electrodeposition coating film, the corrosion resistance after coating is improved.
[0018]
　Hereinafter, the plating layer constituting the aluminum-plated steel sheet according to the present embodiment and the steel sheet on which the plating layer is formed will be described. Although the present embodiment mainly describes the application to the hot stamping member, the application of the aluminum-plated steel sheet according to the present embodiment is not limited to the hot stamping member.
[0019]
(Plating layer) The
　plating layer is formed on the surface of the steel sheet. The plating layer contains Group A elements, the balance of which is composed of Al, Fe and impurities, and may further contain Si. The Al content is preferably 75% or more. It is not necessary to set an upper limit of the Al content in particular, but it is, for example, 99.999%.
　Group A elements are Group 2 elements and 4th period d-block elements in the periodic table. In the present embodiment, the Group 2 elements in the periodic table are Be, Mg, Ca, Sr, Ba, and the 4th period d-block elements are Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn. The plating layer of the aluminum-plated steel sheet according to the present embodiment may contain one or more of these elements.
　In order to improve the adhesion to the electrodeposition coating film and the corrosion resistance after coating, the elements of Group A exclude Fe, Be, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Co, Ni. , Cu, Zn may be limited. Further, among the elements of Group A, even a trace amount of Sr, Mg, or Ca of 0.100% or less is particularly preferable because it significantly improves the adhesion of the electrodeposition coating and the durability after coating.
　The preferred chemical composition of the plating layer is mass%, total content of group A elements: 0.001 to 30.00%, Si: 0 to 20.0%, Fe: 0 to 10.0%. , The chemical composition in which the balance is Al is exemplified. The effect can be obtained if the group A element is contained, but the total content of the group A element is preferably 0.001% or more. In order to further improve the adhesion of the electrodeposited coating film and the corrosion resistance after coating, the lower limit of the total content of group A elements is set to 0.01%, 0.03%, 0.05%, 0.07% or It is more preferable to increase it to 0.09%. As described above, since Sr, Mg, and Ca are effective even in trace amounts, the lower limit of the total content of group A elements is set to A when Sr, Mg, and Ca are contained and when these are not contained. The lower limit of the total content of the group elements may be different values. For example, the lower limit of the total content of Sr, Mg and Ca is set to 0.001%, 0.01%, 0.02%, 0.03%, 0.04%, 0.06% or 0.08%. If the lower limit of the total content of Sr, Mg and Ca does not meet this value, the lower limit of the total content of group A elements is 0.05%, 0.10%, 0.15% or 0.20. May be%. That is, for example, when the total content of Sr, Mg, and Ca is less than 0.001%, the total content of the group A elements may be 0.05% to 30.00%.
　Further, if the total content of the group A elements exceeds 30.00%, the alloy cost of the plating bath and the like will increase, which is not preferable. In order to achieve both the required performance as an automobile member and the manufacturing cost, the upper limit of the total content of group A elements is 15.0%, 10.0%, 5.00%, 3.00%, 2.00%. , 1.50% or 1.00%.
　If the Si content exceeds 20.0%, the amount of alloy produced in the plating bath increases and the frequency of removing the precipitate increases, which is not preferable. Therefore, the upper limit of the Si content is 20.0%. If necessary, the upper limit of the Si content may be 15.0%, 12.0% or 10.0%.
　The upper limit of the Fe content is 10.0%. If necessary, the upper limit of the Fe content may be 7.0%, 5.0% or 4.0%. The content of Si and Fe is not essential, and the lower limit of their content is 0%. If necessary, the lower limits of the Si content and the Fe content may be set to 0.1%, respectively.
　Further, the metal structure of the plating layer may contain one or more of an Al phase, an Al—Si phase, a Si phase, an Al—Fe alloy phase or an Al—Fe—Si alloy phase.
　The plating layer may be formed on both sides of the steel sheet, but may be one side. The chemical composition of the plating layer can be analyzed by the offline X-ray fluorescence method described in Annex JB of JIS G 3314: 2011.
[0020]
(Thickness t of plating layer: 10 to 60 μm)
　The thickness t of the plating layer is in the range of 10 μm to 60 μm. By setting the thickness t to 10 μm or more, the corrosion resistance of the hot stamping member can be improved. Further, when the thickness is 60 μm or less, the Al—Fe intermetallic compound layer is formed up to the outermost layer or near the outermost layer, so that the corrosion resistance of the hot stamping member is improved. The lower limit of the thickness t of the plating layer may be 13 μm, 15 μm, 20 μm or 25 μm, and the upper limit thereof may be 55 μm, 50 μm or 45 μm.
[0021]
　The thickness of the plating layer can be measured by observation using GDS (glow discharge emission spectroscopy) or the like.
　In the present embodiment, the plating layer is determined up to a position where the detection intensity of Al is reduced to 1/20 of the maximum value by using GDS. Specifically, when Al is measured for 1000 seconds at a sputtering rate of 0.060 μm / sec at 0.1 second intervals in the thickness direction from the surface of the plating layer with GDS, the detection intensity is 1 / of the maximum value. The thickness of the plating layer is obtained by multiplying T by the sputtering rate, where the measurement time of 20 is T [seconds]. However, when a plurality of points where the detection intensity of Al is 1/20 of the maximum value are detected, the longest measurement time in which the detection intensity is 1/20 of the maximum value is T [seconds]. Then, the thickness of the plating layer is obtained by multiplying T by the sputtering rate.
[0022]
(Average crystal grain size in the range from the outermost surface of the plating layer to a position (2t / 3 position) 2/3 times the thickness t: 2t / 3 or less and 15 μm or less) From
　the outermost surface of the plating layer to the 2t / 3 position The average crystal grain size of is 2t / 3 (μm) or less and 15 μm or less when the thickness of the plating layer is t. By setting the average crystal grain size to 2 t / 3 (μm) or less and 15 μm or less, the area of ​​the crystal grain boundary becomes large, and the boundary area with the atmospheric gas such as the atmosphere becomes large during the subsequent hot stamp heating. .. As a result, the amount of zinc phosphate crystals precipitated increases. That is, so-called chemical conversion processability is enhanced. Further, this improves the adhesion of the electrodeposition coating film to be electrodeposited after the chemical conversion treatment. By increasing the adhesion of the electrodeposition coating film, the corrosion resistance after coating is improved.
　After hot stamping, as described above, the corrosion resistance after coating is improved, but even without hot stamping, the boundary area with the coating film is as long as the average crystal grain size is 2 t / 3 (μm) or less and 15 μm or less. As the size increases, the adhesion is improved and the corrosion resistance after painting is improved.
[0023]
　The average crystal grain size of the plating layer is determined as follows.
　A sample is taken from the aluminum-plated steel sheet so that the cross section in the thickness direction of the plated layer is the observation surface. The collected sample is etched with a 3% nitric acid alcohol solution (Nital solution) to reveal grain boundaries, and a scanning electron microscope (SEM) is used to include the outermost surface of the plating layer to the steel plate. Take an image. With respect to this photograph, as shown in FIG. 1, a line segment having a length of 2 t / 3 (t = thickness of the plating layer (μm)) is drawn in the thickness direction from the outermost surface of the plating layer, and the intersection with the grain boundary is drawn. The number is n, and the value obtained by dividing the line segment length (2t / 3) by n, that is, (2t / 3n) is defined as the average crystal grain size. As shown in (a), (b), and (c) in the figure, three such line segments are drawn at arbitrary positions at intervals of 5 μm, the average crystal grain size is obtained at each line segment position, and these are obtained. The average value is taken as the average particle size of the plating layer in the range from the outermost surface to the position (2t / 3 position) 2/3 times the thickness t.
　When n is 0, 2t / 3n cannot be calculated, but since the particle size is larger than 2t / 3 in the observation image, it is judged that the average crystal particle size is not 2t / 3 or less.
　Further, in the calculation of the number n of intersections, as described in Annex C.2.2 of JIS G0551: 2013, when the line segment intersects the triple point, n is set to 1.5 at that point.
[0024]
(The maximum value of the detection intensity of the group A element in the range from the outermost surface to the position (t / 3 position) 1/3 times the thickness t of the plating layer is the position 2/3 times the thickness t from the outermost surface. Detection of group A elements in the range
　from the outermost surface to the t / 3 position ( 2.0 times or more of the average value of the detection intensity of group A elements in the range from (2t / 3 position) to 1 times the thickness t) The maximum value of the intensity is 2.0 times or more the average value of the detected intensity of the group A element in the range from the 2t / 3 position to the thickness t position (almost equal to the position of the interface between the plating layer and the steel plate). Is preferable. That is, it is preferable that the group A elements are concentrated at a position close to the surface of the plating layer. In particular, since Sr, Mg and Ca have a high affinity for oxygen, they tend to be concentrated near the surface of the plating layer, and even a small amount of these elements has the effect of significantly improving the corrosion resistance after painting. be.
　By setting the ratio of the detected intensities to 2.0 times or more, the proportion of group A elements on the surface layer of the member after hot stamping increases, and the proportion of group A elements present on the surface of the oxide film layer also increases. .. Therefore, the pH of the chemical conversion treatment liquid at the interface between the hot stamp member and the chemical conversion treatment liquid rises. As a result, the amount of zinc phosphate crystals precipitated during the chemical conversion treatment is increased, and the so-called chemical conversion treatment property is enhanced. Further, this improves the adhesion of the electrodeposition coating film to be electrodeposited after the chemical conversion treatment. As a result, corrosion resistance after painting is improved.
[0025]
　The maximum value of the detection intensity of group A elements in the range from the outermost surface to the position (t / 3 position) 1/3 times the thickness t, and the position 2/3 times the thickness t from the outermost surface (2t / 3). The average value of the detected intensities of the group A elements in the range from the position) to the position (t position) that is 1 times the thickness t is obtained by the following method.
　After measuring the thickness t of the aluminum plating layer as described above, the group A elements were measured by GDS at a sputtering rate of 0.060 μm / sec at 0.1 second intervals in the thickness direction from the surface of the plating layer. , The maximum value of the detection intensity of the group A element in the range from the outermost surface to the t / 3 position and the average value of the detection intensity from the 2 / 3t position to the t / t position are obtained. When a plurality of group A elements are contained, the element having the highest detection intensity is used for judgment. FIG. 2 is an example of the results of measuring the group A elements in the plating layer in the thickness direction from the outermost surface of the plating layer using GDS for the aluminum-plated steel sheet according to the present embodiment.
[0026]
(Steel plate)
　The steel plate included in the aluminum-plated steel sheet according to the present embodiment is not particularly limited as long as it is a steel sheet that can be suitably used for the hot stamping method. As a steel plate applicable to the hot stamping member according to the present embodiment, for example, the chemical composition is mass%, C: 0.1 to 0.4%, Si: 0.01 to 0.60%, Mn: 0. 50 to 3.00%, P: 0.05% or less, S: 0.020% or less, Al: 0.10% or less, Ti: 0.01 to 0.10%, B: 0.0001 to 0. Examples of steel plates containing 0100%, N: 0.010% or less, Cr: 0 to 1.00%, Mo: 0 to 1.00%, and the balance of Fe and impurities can be exemplified. Examples of the form of the steel sheet include steel sheets such as hot-rolled steel sheets and cold-rolled steel sheets. Hereinafter, a preferable range of each component contained in the steel sheet will be described.
[0027]
C: 0.1 to 0.4%
　C is contained to ensure the desired mechanical strength. When the C content is less than 0.1%, sufficient improvement in mechanical strength cannot be obtained, and the effect of containing C becomes poor.
　On the other hand, when the C content exceeds 0.4%, the strength of the steel sheet can be further cured and improved, but the elongation and drawing tend to decrease.
　Therefore, the C content is preferably in the range of 0.1% or more and 0.4% or less in terms of mass%.
[0028]
Si: 0.01 to 0.60%
　Si is one of the strength-improving elements for improving the mechanical strength of steel, and is contained in order to secure the desired mechanical strength as in C. When the Si content is less than 0.01%, it is difficult to exert the strength improving effect, and sufficient improvement in mechanical strength cannot be obtained.
　On the other hand, Si is also an easily oxidizing element. Therefore, when the Si content exceeds 0.60%, the wettability is lowered and non-plating may occur when performing hot-dip Al plating due to the influence of the Si oxide formed on the surface layer of the steel sheet.
　Therefore, it is desirable that the Si content is in the range of 0.01% or more and 0.60% or less in terms of mass%.
[0029]
Mn: 0.50 to 3.00%
　Mn is one of the strengthening elements for strengthening steel and one of the elements for enhancing hardenability. Further, Mn is also effective in preventing hot brittleness due to S, which is one of the impurities. If the Mn content is less than 0.50%, these effects cannot be obtained. Therefore, the Mn content is set to 0.50% or more.
　On the other hand, since Mn is an austenite formation promoting element, if the Mn content exceeds 3.00%, the retained austenite phase may become too large and the strength may decrease.
　Therefore, it is desirable that the Mn content is in the range of 0.50% or more and 3.00% or less in terms of mass%.
[0030]
P: 0.05% or less
　P is an impurity contained in steel. P contained in the steel sheet may segregate at the grain boundaries of the steel sheet to reduce the toughness of the base material of the hot-stamped molded product, and may reduce the delayed fracture resistance of the steel sheet. Therefore, the P content of the steel sheet is preferably 0.05% or less, and the P content is preferably as small as possible. The P content may be 0%.
[0031]
S: 0.020% or less
　S is an impurity contained in steel. S contained in the steel sheet may form sulfide to reduce the toughness of the steel sheet and reduce the delayed fracture resistance of the steel sheet. Therefore, the S content of the steel sheet is preferably 0.020% or less, and the S content of the steel sheet is preferably as small as possible. The S content may be 0%.
[0032]
Al: 0.10% or less
　Al is generally used for the purpose of deoxidizing steel. However, when the Al content is high, the Ac3 point of the steel sheet increases. When the Ac3 point of the steel sheet rises, it is necessary to raise the heating temperature required for ensuring the hardenability of the steel during hot stamping, which is not desirable in the production of hot stamping. Therefore, the Al content of the steel sheet is preferably 0.10% or less. It is more preferably 0.05% or less, still more preferably 0.01% or less.
[0033]
Ti: 0.01 to 0.10%
　Ti is one of the elements having an effect of improving the strength of steel. Ti is also an element having an effect of improving oxidation resistance. When the Ti content is less than 0.01%, the strength improving effect and the oxidation resistance improving effect cannot be obtained, and when the Ti content is 0.01% or more, these effects are exhibited.
　On the other hand, if Ti is excessively contained, for example, carbides and nitrides may be formed to soften the steel. In particular, when the Ti content exceeds 0.10%, there is a high possibility that the desired mechanical strength cannot be obtained.
　Therefore, the Ti content is preferably in the range of 0.01% or more and 0.10% or less in terms of mass%.
[0034]
B: 0.0001 to 0.0100%
　B is an element that acts during quenching and has the effect of improving the strength of steel. When the B content is less than 0.0001%, such a strength improving effect is low.
　On the other hand, when the B content exceeds 0.0100%, inclusions may be formed to make the steel sheet brittle and the fatigue strength may decrease.
　Therefore, it is desirable that the B content is in the range of 0.0001% or more and 0.0100% or less in terms of mass%.
[0035]
N: 0.010% or less
　N is an impurity contained in steel. N contained in the steel sheet may form a nitride to reduce the toughness of the steel sheet. Further, when B is contained in the steel sheet, N contained in the steel sheet may combine with B to reduce the amount of solid solution B and reduce the hardenability improving effect of B. Therefore, the N content of the steel sheet is preferably 0.010% or less, and the N content of the steel sheet is more preferably as small as possible. The N content may be 0%.
[0036]
　Further, the aluminum-plated steel sheet according to the present embodiment may further contain Cr, Mo, Cu, Ni, Nb, Sn, and Ca in the following range. However, since these elements are not essential, the lower limit is 0%.
[0037]
Cr: 0 to 1.00%
Mo: 0 to 1.00% In
　order to improve the hardenability of the steel sheet, either one or both of Cr and Mo may be contained. In order to obtain the effect, the content is preferably 0.01% or more. On the other hand, even if the content is 1.00% or more, the effect is saturated and the cost increases. Therefore, the content is preferably 1.00% or less.
[0038]
　Cu: 0 to 1.00%
　Ni: 0 to 2.00%
　Cu and Ni have the effect of increasing the strength of the hot stamping member (steel plate after hot stamping). Therefore, it may be contained if necessary.
　When the above effect is desired, it is preferable to contain Cu or Ni in an amount of 0.01% or more, respectively.
　On the other hand, even if the Cu content exceeds 1.00% and the Ni content exceeds 2.00%, the effect is saturated and the cost increases. Therefore, it is preferable that the Cu content is 1.00% or less and the Ni content is 2.00% or less.
[0039]
　Nb: 0 to 1.00%
　Nb is an element having an action of increasing the strength of the hot stamp member through the miniaturization of the metal structure. In order to obtain this effect, it may be contained if necessary.
　When the above effect is desired, the Nb content is preferably 0.01% or more.
　On the other hand, even if the Nb content exceeds 1.00%, the effect is saturated and the cost increases. Therefore, the Nb content is preferably 1.00% or less.
[0040]
　Sn: 0 to 1.00%
　Sn is an element that improves the corrosion resistance of steel in a corrosive environment. Therefore, it may be contained. In order to obtain the above effects, the Sn content is preferably 0.01% or more.
　However, when the Sn content exceeds 1.00%, the grain boundary strength decreases and the toughness decreases. Therefore, the Sn content when contained is preferably 1.00% or less.
[0041]
　Ca: 0 to 0.10%
　Ca is an element having an action of improving the toughness of the hot stamp member by adjusting the shape of inclusions. Therefore, it may be contained as needed. When the above effect is desired, the Ca content is preferably 0.01% or more.
　On the other hand, when the Ca content is more than 0.10%, not only the above effect is saturated but also an excessive cost is generated. Therefore, even when it is contained, the Ca content is preferably 0.10% or less.
[0042]
　The rest other than the above components are Fe and impurities. The steel sheet may contain other impurities that are mixed in during the manufacturing process. Examples of impurities include the above-mentioned P (phosphorus), N (nitrogen), S (sulfur), and other impurities such as Zn (zinc) and Co (cobalt).
[0043]
　(Hot stamping member) A hot stamping member
　can be obtained by heating and quenching the above-mentioned aluminum-plated steel sheet by a hot stamping method. When the aluminum-plated steel sheet has the above-mentioned preferable chemical composition, it can be made into a hot stamping member having a tensile strength of about 1000 MPa or more by hot stamping.
　Further, in the hot stamping method, since the press working can be performed in a state of being softened at a high temperature, it can be easily molded.
　In the above-mentioned aluminum-plated steel sheet, the area (interface area) of the interface between the steel sheet and the atmospheric gas such as air becomes large when the hot stamp is heated. Since the group A elements have a high affinity with the atmospheric gas, the amount of the group A elements concentrated on the surface layer increases, and the proportion of the group A elements on the outermost surface of the oxide film layer increases. FIG. 3 is an example of the results of measuring the group A elements in the thickness direction from the outermost surface of the oxide film layer using GDS in the hot stamping member obtained by hot stamping the aluminum-plated steel sheet according to the present embodiment. be.
　In the hot stamping process, the aluminum-plated steel plate is heated above the melting point of the plating layer to melt the plating layer (Al plating layer), and at the same time, Fe and Al are mutually diffused between the steel plate and the Al plating layer. By changing the Al phase in the Al plating layer to an Al—Fe alloy phase, an Al—Fe intermetallic compound layer is formed. When Si is contained in the Al plating layer, the Al phase in the Al plating layer also changes to the Al—Fe—Si alloy phase. The melting point of the Al—Fe alloy phase and the Al—Fe—Si alloy phase is about 1150 ° C., which is higher than the upper limit of the heating temperature in the general hot stamping process. Precipitates to form an Al—Fe intermetallic compound layer. There are a plurality of types of Al—Fe alloy phase and Al—Fe—Si alloy phase, and when high temperature heating or long-term heating is performed, the alloy phase changes to an alloy phase having a higher Fe concentration. Further, when the group A element is contained in the Al-Fe intermetallic compound layer, the group A element may exist in various forms such as an intermetallic compound and a solid solution.
[0044]
　(Oxide film layer on the surface layer of the hot stamping member)
　The surface side of the hot stamping member obtained by hot stamping the aluminum-plated steel sheet according to the present embodiment (the surface layer portion of the plating layer of the aluminum-plated steel sheet before hot stamping (opposite to the steel sheet). An oxide film layer is formed as the outermost surface layer of the hot stamping member on the portion (corresponding to the side). This oxide film layer is formed by oxidizing the surface layer of the plating layer of the aluminum-plated steel sheet in the process of heating the hot stamp when manufacturing the hot stamp member. The oxide film layer is composed of group A elements, Al, oxygen, and impurities. The oxide film layer may further contain either or both of Fe and Si. Some of Fe and Si contained in the Al-Fe intermetallic compound layer may be mixed during the formation of the oxide film layer.
　The group A elements contained in the oxide film layer are group 2 elements and 4th period d-block elements in the periodic table. In the present embodiment, the Group 2 elements in the periodic table are Be, Mg, Ca, Sr, Ba, and the 4th period d-block elements are Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn. If the oxide film layer of the hot stamping member obtained by hot stamping the aluminum-plated steel sheet according to the present embodiment contains one or more of these elements, an effect of improving paint adhesion can be obtained. The group A element mainly exists as an oxide, but a part of the group A element may exist as a simple substance or in the form of a compound other than the oxide. Also, the form of the oxide is not limited. Among the oxide film layers, elements other than group A elements may also exist in the form of oxides. For example, it is preferable that Al exists as aluminum oxide and other impurities exist as oxides of each impurity. Further, Si when Si is contained in the oxide film layer preferably exists as silicon oxide, and Fe when Fe is contained is preferably present as iron oxide. Further, each of the group A elements, Al, Si, and Fe may be contained in the form of a composite oxide together with other elements.
[0045]
　Oxides of group A elements are classified as basic oxides. In the chemical conversion treatment step, when the basic oxide containing the group A element (particularly present on the surface of the oxide film layer) in the oxide film comes into contact with the phosphor oxidation conversion treatment solution (hereinafter referred to as the chemical conversion treatment solution), A part of it dissolves to raise the solution pH at the interface between the chemical conversion treatment liquid and the oxide film layer provided in the hot stamp member. On the other hand, the solubility of zinc phosphate contained in the chemical conversion treatment liquid decreases as the pH increases, and the amount of precipitated crystals increases. Therefore, as the pH at the interface between the surface of the oxide film layer and the chemical conversion treatment liquid increases, the number of zinc phosphate crystals precipitated on the surface of the oxide film layer increases.
[0046]
(Manufacturing Method of Aluminum Plated Steel Sheet and Manufacturing Method of Hot Stamping Member)
　Next, an example of the manufacturing method of the aluminum plated steel sheet and the hot stamping member according to the present embodiment will be described. In the manufacturing method described below, Al plating is applied to a steel sheet to obtain an aluminum-plated steel sheet, and the aluminum-plated steel sheet is subjected to a hot stamping step to form an Al-Fe metal-to-metal compound layer and an oxide film layer on the surface of the steel sheet. This is an example of However, the method described here is an example and is not particularly limited to this method.
[0047]

(Immersion in a plating bath)
　For example, an Al-plated layer is formed on the surface of a steel sheet by a hot-dip plating method. The plating layer (Al plating layer) of the aluminum-plated steel sheet is formed on one side or both sides of the steel sheet.
　At least a part of Al contained in the Al plating layer can be alloyed with Fe in the steel sheet at the time of hot-dip plating or the heating process in hot stamping. Therefore, this Al plating layer is not always formed of a single layer having a constant component, and may include an appropriately alloyed layer.
[0048]
　The hot-dip plating bath in the hot-dip plating method contains Al and group A elements. Further, Si may be contained in the hot-dip plating bath. The group A element added to the hot-dip plating bath is 0.001% by mass or more and 30.00% by mass or less, and Si is 20.0% by mass or less. An Al plating layer is formed on the surface of the steel sheet by immersing the steel sheet in a hot-dip plating bath containing Al, group A elements and, if necessary, Si. The formed Al plating layer contains Group A elements. In addition, Si may be contained.
　Further, after immersion in the plating bath, the amount of plating adhered is adjusted by gas wiping or the like, but the atmosphere (particularly oxygen concentration) at the time of gas wiping affects the concentration of group A elements. The maximum value of the detection intensity of group A elements in the range (surface to t / 3) from the outermost surface of the plating layer to the position 1/3 times the thickness t, and the thickness t from the position 2/3 times the thickness t. When increasing the ratio to the average value of the detection intensity of group A elements in the range up to 1 times the position (2t / 3 to t), the oxygen concentration in the atmosphere during gas wiping may be more than 5% by volume. It is preferable to have an air atmosphere having an oxygen concentration of about 20% by volume.
[0049]
(Particle spraying)
　Next, the nitride, nitride, before the molten metal (plated metal in the molten state) adhering to the steel sheet solidifies by immersing the steel sheet immediately after being pulled up from the hot-dip plating bath in the hot-dip plating bath. Particles such as carbides and oxides are sprayed together with air and cooling gas such as nitrogen and argon. The sprayed particles become crystal nuclei, which has the effect of reducing the crystal grain size of the Al plating layer in the solidified plating metal. This effect is particularly large on the surface side where the particles are sprayed.
　By reducing the crystal grain size of the Al plating layer, the crystal grain boundaries increase, and the boundary area with the atmospheric gas such as the atmosphere increases during the subsequent hot stamp heating. Since the group A element has a high affinity with the atmospheric gas, the group A element is concentrated on the surface layer of the plating layer when the hot stamp is heated, and the ratio of the group A element on the outermost surface of the oxide film layer of the hot stamp member is increased. It gets higher.
　The spraying speed of the particles is preferably 30 to 70 m / s in the direction perpendicular to the steel plate surface. The sprayed particles have the effect of cooling the plated metal in a molten state at the same time as becoming the core of the crystal. When the spraying speed of the particles is less than 30 m / s, the cooling rate is insufficient and the number of crystal nuclei is reduced because the boundary area with the plating metal in contact per unit time is small. As a result, the crystal grain size becomes large even after hot stamping, and the paint adhesion and the corrosion resistance after painting are inferior. On the other hand, if the spraying speed of the particles is higher than 70 m / s, the unevenness of the plated metal becomes large due to the spraying of the particles, so that the unevenness becomes too large even after hot stamping, and the corrosion resistance after painting deteriorates. ..
[0050]
　The size of particles such as nitrides, carbides, and oxides to be sprayed is not particularly limited. However, if the particle size exceeds 20 μm, the crystal grains of the Al plating layer become large, and it becomes difficult for the group A elements to concentrate on the surface layer during hot stamping. Therefore, it is desirable that the particles have a particle size of 20 μm or less. Examples of the nitride, carbide and oxide to be sprayed include titanium nitride, silicon nitride, titanium carbide, silicon carbide, titanium oxide, silicon oxide, iron oxide and aluminum oxide. The amount of particles adhered is preferably, for example, 0.01 to 1.0 g / m 2 . By setting the amount of particles adhered within this range, a sufficient amount of crystal nuclei are formed in the Al plating layer, particularly the surface layer portion of the plating layer. Therefore, the crystal grain size of the Al plating layer becomes sufficiently small, and the group A element can be concentrated on the surface layer portion of the oxide film layer by heating at the time of hot stamping.
[0051]
A
　hot stamping member can be obtained by performing hot stamping on the aluminum-plated steel sheet manufactured as described above. In the hot stamping method, the aluminum-plated steel sheet is blanked (punched) as necessary, and then the aluminum-plated steel sheet is heated to soften it. Then, the softened aluminum-plated steel sheet is pressed and formed, and then cooled. It may be cooled at the same time as molding. The steel sheet is hardened by heating and cooling to obtain a high tensile strength of about 1000 MPa or more. As a heating method, infrared heating or the like can be adopted in addition to a normal electric furnace and a radiant tube furnace.
[0052]
　In the case of an atmospheric atmosphere, the heating temperature and heating time at the time of hot stamping are preferably 850 to 950 ° C. for 2 minutes or more. If the heating time is shorter than 2 minutes, the concentration of the group A elements in the oxide film layer does not proceed, so that the effect of improving the paint adhesion and pitting corrosion resistance of the hot stamp member tends to be insufficient.
　When hot stamping is performed in an atmosphere having an oxygen concentration of 5% or less, the heating time is preferably 3 minutes or more. When the oxygen concentration is low, if the heating time is shorter than 3 minutes, the thickness of the oxide film layer will not be sufficiently large. Is insufficiently concentrated.
　It is not necessary to limit the upper limit of the heating time, but it is preferably 10 minutes or less. If it is longer than 10 minutes, productivity will be low and it will be economically disadvantageous.
[0053]
　The hot stamping changes the Al plating layer into an Al-Fe intermetallic compound layer, and an oxide film layer is formed on the surface of the Al-Fe intermetallic compound layer. The Al plating layer is melted by heating during hot stamping, and Fe is diffused from the steel plate to form an Al—Fe intermetallic compound layer containing an Al—Fe alloy phase and an Al—Fe—Si alloy phase. .. The Al-Fe intermetallic compound layer is not always formed of a single layer having a constant component composition, and may include a partially alloyed layer.
[0054]
　Further, the group A elements contained in the Al plating layer are concentrated on the surface layer of the Al plating layer, and the surface of the Al plating layer is oxidized by oxygen in the atmosphere to form an oxide film layer containing the group A elements. Will be done. By spraying the particles, a sufficient amount of crystal nuclei are formed in the Al plating layer, particularly the surface layer portion. Therefore, the crystal grain size of the Al plating layer becomes sufficiently small, and the group A element can be concentrated on the surface layer portion of the oxide film layer formed by hot stamping by hot stamping. All of the group A elements contained in the Al plating layer may be transferred to the oxide film layer, or a part of the elements may remain in the Al-Fe intermetallic compound layer and the rest may be transferred to the oxide film layer. good.
[0055]
　Further, instead of hot-dip plating, Al and group A elements are adhered to the surface of the steel sheet by vapor deposition or thermal spraying to form an Al coating layer containing the group A elements, and further, the steel sheet having the Al coating layer is hot. By stamping, the hot stamping member according to the present embodiment may be manufactured.
　Further, as an example of the method for forming the Al coating layer, Al may be first adhered to the steel sheet by vapor deposition or thermal spraying, and then the group A element may be adhered. As a result, an Al coating layer composed of an Al layer and group A elements is formed.
　Further, as another example of the method of forming the Al coating layer, even if the vapor deposition or thermal spraying is performed using a vapor deposition source or a thermal spraying source containing Group A elements, Al and Group A elements are simultaneously adhered to the steel sheet. good. The ratio of the group A elements in the Al coating layer is preferably 0.001% to 30.00% by mass.
[0056]
　Then, as in the case of the aluminum-plated steel sheet, by hot-stamping the steel sheet having the Al-coated layer, a hot-stamping member having an oxide film layer containing Group A elements, Al, and oxygen can be produced.
Example
[0057]
　Hereinafter, examples of the present invention will be described, but the conditions in the examples are one condition example adopted for confirming the feasibility and effect of the present invention, and the present invention is limited to this one condition example. It's not a thing. The present invention may adopt various conditions as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
[0058]
　The steel sheet before plating has high mechanical strength (meaning various properties related to mechanical deformation and fracture such as tensile strength, yield point, elongation, drawing, hardness, impact value, and fatigue strength). It is desirable to use. Table 1 shows the chemical composition of the steel sheet before plating used for the steel sheet of the present invention.
[0059]
[table 1]

[0060]
　Al plating layers were formed on both sides of the steel sheets by the hot-dip plating method for the symbols A1 to A66, a1 to a10 and B1 to B11 using the steel sheets having the chemical components shown in Table 1 (steel Nos. S1 to S23). .. The plating bath temperature during hot-dip plating was 700 ° C., and after immersing the steel sheet in the plating bath, the amount of adhesion was adjusted to 16 to 115 g / m 2 per side by a gas wiping method . After that, for the examples excluding the symbols a4 and a5, before the plating layer solidifies , the particle size is such that the average adhesion amount is 0.1 g / m 2 at the spraying rates shown in Tables 2A, 2B, and 2C. A 0.05 μm titanium oxide was sprayed. No particles were sprayed on the symbols a4 and a5. The atmosphere at the time of gas wiping was a normal atmosphere except for the symbols B1, B4, and B8. For reference numerals B1, B4, and B8, the atmosphere during gas wiping was set to an oxygen concentration of 5% by volume and a nitrogen concentration of 95% by volume, and the oxygen concentration was lower than that of a normal atmosphere.
[0061]
　As shown in Tables 2A to 2C and Table 3, the plating bath contained Group A elements in an amount of 0.001% or more and 30.00% or less in terms of mass%. As the group A element, one or more of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mg, Ca, Ba, Sr, and Be were selected. In Table 2B, when a plurality of group A elements are contained, the content (unit: mass%) of each is shown. The rest of the plating bath was Al and impurities.
[0062]
　For the obtained plated steel sheet, the composition of the plated layer is analyzed by JIS G3314: 2011, the thickness of the plated layer is measured by GDS, and the thickness t is 2 from the outermost surface of the plated layer by SEM observation after nital corrosion. The average crystal grain size in the thickness range up to the / 3 times position was determined.
　The results are shown in Tables 2A to 2C and Table 3. The rest of the plating layer was Al and impurities.
[0063]
　Further, for some aluminum-plated steel sheets (reference numerals B1 to B11), using GDS, A at a sputtering rate of 0.060 μm / sec at 0.1 second intervals in the thickness direction from the surface of the plating layer. The group elements are measured, and the maximum value of the detection intensity of the group A element in the range (surface to t / 3) from the outermost surface of the plating layer to the position 1/3 times the thickness t and the above 2/3 of the thickness t. I (M) / I (A), which is the ratio to the average value of the detected intensities of the group A elements in the range (2t / 3 to t) from the double position to the position of 1 times the thickness t, was determined.
　The results are shown in Table 3.
[0064]
　Then, the aluminum-plated steel sheet was heated in an electric resistance furnace at a furnace temperature of 900 ° C. in an air atmosphere so that the soaking time was 5 minutes. Then, at the same time as molding with a die, it was cooled with a die to obtain a hot stamp member.
[0065]
　The obtained hot stamping members were investigated for paint adhesion and post-painting corrosion resistance by the methods shown below. The results are shown in Tables 2A to 2C and Table 3.
　Although not shown in the table, the thickness of the Al—Fe intermetallic compound layer was in the range of 0.1 to 10.0 μm in all the examples.
[0066]
1) Paint adhesion The
　paint adhesion was evaluated according to the method described in Japanese Patent No. 4373778. That is, based on the area ratio calculated by immersing the sample in deionized water at 60 ° C. for 240 hours, cutting 100 grids at 1 mm intervals with a cutter, and visually measuring the number of peeled portions of the grids. Scored.
(Score)
3: Peeling area 0% or more and less than 10%
2: Peeling area 10% or more and less than 70%
1: Peeling area 70% or more and 100% or less
[0067]
(2) Corrosion resistance
　after painting Corrosion resistance after painting was evaluated by the neutral salt spray cycle test method specified in JIS H8502: 1999. A cross-cut flaw was made in the coating film with a diamond cutter, and the width (maximum value on one side) of the coating film swelling from the cut flaw after 180 cycles of the corrosion test was measured. If the evaluation is 2 or 3 according to the following criteria, it is judged that the corrosion resistance after painting is excellent.
(Evaluation)
3: Swelling width 0 mm or more and less than 1.5 mm
2: Swelling width 1.5 mm or more and less than 3 mm
1: Swelling width 3 mm or more
　Invention Examples A1 to A66 and B1 to B11 were excellent in paint adhesion. As a result, the corrosion resistance after painting was also excellent. On the other hand, Comparative Example a1 in which the plating layer does not contain Group A elements, and a2, a3, a6, a7, a8, a9, and a10 in which the thickness and / or crystal grain size of the plating layer are outside the scope of the invention are shown. It was inferior in paint adhesion and corrosion resistance after painting. Further, in a4 and a5, since the particles were not sprayed, the average particle size of the plating layer was large. As a result, the elements of Group A did not concentrate on the surface layer of the oxide film layer, and the paint adhesion and the corrosion resistance after painting were inferior.
[0068]
[Table 2A]

[0069]
[Table 2B]

[0070]
[Table 2C]

[0071]
[Table 3]

[0072]
　Although the preferred embodiments of the present invention have been described in detail above, it goes without saying that the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.
Industrial applicability
[0073]
　According to the present invention, it is possible to provide an aluminum-plated steel sheet having excellent adhesion to an electrodeposition coating film (paint adhesion). Therefore, it has high industrial applicability.
The scope of the claims
[Claim 1]
　It has a steel plate and
　a plating layer formed on the surface of the steel plate, and the
　plating layer is Be, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu. The
　plating layer has a thickness t of 10 to 60 μm, and is
　the most of the plating layer.
An aluminum-plated steel sheet having an average crystal grain size of 2 t / 3 or less and 15 μm or less in a thickness range from the surface to a position 2/3 times the thickness t .
[Claim 2]
　The chemical composition of the plating layer is mass%,
　the total content of the group A elements: 0.001 to 30.00%,
　Si: 0 to 20.0%,
　Fe: 0 to 10.0%, the
　balance. :
　The aluminum-plated steel sheet according to claim 1, which is Al and impurities .
[Claim 3]
　In the chemical composition of the plating layer,
　the total content of Sr content, Mg content and Ca content is less than 0.001% in mass%, and the total content of the
　group A elements is 0.05 to 30.
　The aluminum-plated steel sheet according to claim 1 or 2, wherein the content is 0.00% .
[Claim 4]
　When the group A element in the plating layer is measured from the outermost surface of the plating layer in the thickness direction using GDS,
　　the position from the outermost surface of the plating layer to 1/3 times the thickness t. The maximum value of the detection intensity of the group A element in the range up to is the average value of the detection intensity of the group A element in the range from the position of 2/3 times the thickness t to the position of 1 times the thickness t. The
aluminum-plated steel sheet according to any one of claims 1 to 3, which is 2.0 times or more the amount of the above .
[Claim 5]
　The chemical composition of the steel plate is
　C: 0.1 to 0.4%,
　Si: 0.01 to 0.60%,
　Mn: 0.50 to 3.00%,
　P: 0.05% in terms of mass %. Below,
　S: 0.020% or less,
　Al: 0.10% or less,
　Ti: 0.01 to 0.10%,
　B: 0.0001 to 0.0100%,
　N: 0.010% or less,
　Cr: 0 to 1.00%,
　Mo: 0 to 1.00%,
　Cu: 0 to 1.00%,
　Ni: 0 to 2.00%,
　Nb: 0 to 1.00%,
　Sn: 0 to 1.00. The aluminum-plated steel sheet according to any one of claims 1 to 4, wherein the content is%,
　Ca: 0 to 0.10%, and the
balance: Fe and impurities
.
[Claim 6]
　The aluminized steel sheet according to any one of claims 1 to 5 is heated to a temperature range of 850 ~ 950 ° C.,
　was maintained for more than two minutes at the temperature range, performing hot stamping,
and wherein the hot Manufacturing method of stamp member.
[Claim 7]
　A hot stamping member obtained by hot stamping the aluminum-plated steel sheet according to any one of claims 1 to 5
　, wherein Be, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, etc. A
hot stamping member having an oxide film layer containing one or more kinds of group A elements selected from the group consisting of Mn, Fe, Co, Ni, Cu, and Zn, Al, and oxygen. ..