Invention name: Hot stamp molded article
Technical field
[0001]
　The present invention relates to a hot stamped article.
　The present application claims priority based on Japanese Patent Application No. 2019-157206 filed in Japan on August 29, 2019, the contents of which are incorporated herein by reference.
Background technology
[0002]
　In recent years, it has been required to curb the consumption of chemical fuels in order to protect the environment and prevent global warming. Such a request is no exception to, for example, automobiles, which are indispensable for daily life and activities as a means of transportation. In response to such demands, automobiles are being considered for improving fuel efficiency by reducing the weight of the vehicle body. Since most of the structure of an automobile is made of iron, especially a steel plate, thinning the steel plate to reduce the weight has a great effect on reducing the weight of the vehicle body. However, if the thickness of the steel sheet is simply reduced to reduce the weight of the steel sheet, there is a concern that the strength of the structure will decrease and the safety will decrease. Therefore, in order to reduce the thickness of the steel sheet, it is required to increase the mechanical strength of the steel sheet used so as not to reduce the strength of the structure.
　Therefore, research and development are being carried out on a steel sheet that can maintain or increase its mechanical strength even if it is thinner than the previously used steel sheet by increasing the mechanical strength of the steel sheet. Requests for such steel sheets are made not only in the automobile manufacturing industry but also in various manufacturing industries.
[0003]
　In general, a material having high mechanical strength tends to have low shape freezing property in molding processing such as bending, and 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 pressing method (hot stamping method, high temperature pressing method, diquenching method)". In this hot pressing method, the material to be molded is once heated to a high temperature, and the material softened by heating is pressed and molded, or then cooled at the same time as molding.
[0004]
　According to this hot pressing method, the material is once heated to a high temperature to be softened and pressed in a state where the material is softened, so that the material can be easily pressed. Therefore, by this hot press working, a press-molded product having both good shape freezing property and high mechanical strength can be obtained. In particular, when the material is steel, the mechanical strength of the press-molded product can be increased by the quenching effect due to cooling after molding.
[0005]
　However, when this hot pressing method is applied to a steel sheet, for example, by heating to a high temperature of 800 ° C. or higher, iron or the like on the surface is oxidized to generate scale (oxide). Therefore, after hot pressing, a step of removing this scale (descaling step) is required, and the productivity is lowered. Further, for a member or the like that requires corrosion resistance, since it is necessary to apply a rust preventive treatment or a metal coating to the surface of the member after processing, a surface cleaning step and a surface treatment step are required, which also reduces productivity.
[0006]
　As an example of a method for suppressing such a decrease in productivity, it is considered to improve the corrosion resistance and omit the descaling step by applying a coating such as plating to the steel sheet before hot stamping.
[0007]
　As such a plated steel material, for example, in Patent Document 1, an Al—Zn-based alloy plating layer containing Al: 20 to 95% by mass, Ca + Mg: 0.01 to 10% by mass, and Si is provided on the surface of a steel sheet. A plated steel sheet for hot pressing, which is characterized by having, is disclosed. According to Patent Document 1, scale formation is suppressed during heating before hot pressing, plating does not adhere to the die during hot pressing, and the obtained hot pressed member has a good appearance. It is disclosed that it has excellent coating adhesion and corrosion resistance.
[0008]
　Further, Patent Document 2 provides a base layer made of steel provided for molding into a part by hot pressing and coated with a metal protective coating formed of Zn or a Zn alloy to protect it from corrosion. In a steel sheet product having A steel sheet product characterized by this is disclosed.
[0009]
　Further, Patent Document 3 discloses a plated steel material in which a plating layer containing an Al—Fe alloy layer and a Zn—Mg—Al alloy layer is provided on the surface of the steel material, and the corrosion resistance is dramatically improved.
[0010]
　Members obtained by hot-stamping steel materials as described above are often applied to automobile parts, and when applied as automobile parts, the members are generally bonded. However, in Patent Documents 1 to 3, the adhesiveness of the hot stamped molded product is not examined at all.
　As a result of the study by the present inventors, when a general adhesive bonding for automobiles is performed on a member obtained by hot stamping a steel sheet having a plating layer containing Al or Zn, adhesiveness (adhesive durability) It turned out that it may not be possible to secure.
Prior art literature
Patent documents
[0011]
Patent Document 1: Japanese Patent Application Laid-Open No. 2012-112010
Patent Document 2: Japanese
Patent Application Laid-Open No. 2014-514436 Patent Document 3: Japanese Patent Application Laid-Open No. 2017-66459
Outline of the invention
Problems to be solved by the invention
[0012]
　The present invention has been made in view of the above problems. An object of the present invention is to provide a hot stamp molded product that exhibits excellent adhesiveness.
Means to solve problems
[0013]
　The present inventors control the composition balance of the plating layer of the molten Zn-Al-Mg plated steel sheet and the conditions at the time of manufacturing to form an oxide film on the surface that contributes to the improvement of the adhesiveness, thereby achieving the adhesiveness. It was found that an excellent hot-stamped molded product can be obtained.
　The present invention has been completed based on the above findings, and the gist thereof is as follows.
[0014]
　(1) The hot stamp molded body according to one aspect of the present invention includes a base material made of iron, a plating layer formed on the surface of the base material, and an oxide film formed on the surface of the plating layer. The chemical composition of the plating layer is, in mass%, Al: 20.00 to 45.00%, Fe: 10.00 to 45.00%, Mg: 4.50 to 15.00%, Si :. 0.10 to 3.00%, Ca: 0.05 to 3.00%, Sb: 0 to 0.50%, Pb: 0 to 0.50%, Cu: 0 to 1.00%, Sn: 0 ~ 1.00%, Ti: 0 to 1.00%, Sr: 0 to 0.50%, Cr: 0 to 1.00%, Ni: 0 to 1.00%, Mn: 0 to 1.00% , The balance is Zn and impurities, and the chemical composition of the oxide film is atomic%, Mg: 20.0 to 55.0%, Ca: 0.5 to 15.0%, Zn: 0. ~ 15.0%, Al: 0% or more and less than 10.0%, the balance is O and impurities of 5.0% or less in total, and the amount of one-sided adhesion of the oxide film is 0.01 to 10 g. / M 2 .
(2) In the hot stamp molded product according to (1) above, the chemical composition of the plating layer is mass%, Al: 25.00 to 35.00%, Mg: 6.00 to 10.00%. , 1 or 2 may be contained.
(3) The hot stamp molded product according to (1) or (2) above may contain the chemical composition of the oxide film in atomic% and Mg: 35.0 to 55.0%. good.
The invention's effect
[0015]
　According to the above aspect of the present invention, it is possible to provide a hot stamp molded product that exhibits excellent adhesiveness.
A brief description of the drawing
[0016]
FIG. 1 is a schematic view showing a hot stamp molded body according to the present embodiment.
FIG. 2 is a diagram showing an example of an oxide film of a hot stamp molded product according to the present embodiment.
[Fig. 3] Example No. It is a figure which shows an example of the oxide film of the hot stamping compact of 11 (comparative example).
Embodiment for carrying out the invention
[0017]
　A hot stamped body according to an embodiment of the present invention (a hot stamped body according to the present embodiment) will be described with reference to the drawings.
　With reference to FIG. 1, the hot stamp molded body 1 according to the present embodiment has a base material 2 made of steel, a plating layer 3 formed on the surface of the base material 2, and an oxidation formed on the surface of the plating layer 3. It is provided with a material film 4. In FIG. 1, the plating layer 3 and the oxide film 4 are formed on only one side of the base material 2, but may be formed on both sides.
[0018]

　The base material 2 is made of steel. The base material 2 is, for example, a hot stamping member obtained by hot stamping a steel plate. Therefore, although it has a plate shape in FIG. 1, the shape is not limited.
　Further, in the hot stamp molded body 1 according to the present embodiment, the plating layer 3 and the oxide film 4 are important, and the chemical composition of the base material 2 and the like are not particularly limited. For the base material 2, the steel to be plated and hot stamped may be determined according to the applicable product, the required strength, the plate thickness, and the like. For example, as the base material, a hot-rolled steel sheet described in JIS G3193: 2008 or a cold-rolled steel sheet described in JIS G3141: 2017 can be used.
[0019]

[Chemical composition]
　Hereinafter,% of the chemical composition of the plating layer is mass% unless otherwise specified.
[0020]
Al: 20.00 to 45.00%
　Al is an essential element for improving the corrosion resistance of the plating layer 3. Further, if the Al content is less than 20.00%, an intermetallic compound mainly composed of Ca and Al, which is a source of Ca to the outermost surface of the plating layer at the time of hot stamping, cannot be produced. As a result, Zn and Mg evaporate, and MgO and ZnO that lower the adhesiveness are formed on the surface of the plating layer, and the adhesiveness is lowered. Therefore, the Al content is set to 20.00% or more. It is preferably 25.00% or more.
　On the other hand, when the Al content exceeds 45.00%, Al-based oxides such as Al 2 O 3 that lower the adhesiveness are formed, so that the adhesiveness is lowered. Therefore, the Al content is set to 45.00% or less. It is preferably 35.00% or less.
[0021]
When the plated steel sheet is heated during Fe: 10.00 to 45.00%
　hot stamping, Fe diffuses from the base metal 2 to the plating layer 3, so that the plating layer 3 of the hot stamping compact 1 always contains Fe. ..
　When the Fe content is less than 10.0%, the spot weldability and the weldability tend to deteriorate, so the Fe content is set to 10.00% or more.
　On the other hand, if the Fe content is too high, the corrosion resistance tends to deteriorate, so the Fe content is set to 45.00% or less.
[0022]
Mg: 4.50 to 15.00%
　Mg is an element that contributes to the improvement of the corrosion resistance of the plating layer 3. Further, Mg has an effect of suppressing LME cracking because it binds to the Zn component in the plating layer 3 to prevent the generation of liquid phase Zn when the hot stamp is heated. Further, in the hot stamp molded body 1 according to the present embodiment, Mg is an element that forms an oxide film 4 and improves adhesiveness. In order to obtain these effects, the Mg content is set to 4.50% or more. When the Mg content is less than 4.50%, the Al-based oxide that lowers the adhesiveness to the oxide film 4 increases. The Mg content is preferably 6.00% or more.
　On the other hand, when the Mg content exceeds 15.00%, sacrificial anticorrosion works excessively, and the corrosion resistance of the plating layer 3 tends to decrease. In addition, the oxide film 4 becomes brittle and the adhesiveness is lowered. Therefore, the Mg content is set to 15.00% or less. It is preferably 10.00% or less.
[0023]
Si: 0.10 to 3.00%
　Si is an element that forms a compound together with Mg and contributes to the improvement of corrosion resistance. Further, when the Si content is less than 0.10%, Zn and Mg evaporate during hot stamping, and MgO and ZnO that lower the adhesiveness are formed on the surface, so that the adhesiveness is lowered. Therefore, the Si content is set to 0.10% or more.
　On the other hand, even if the Si content exceeds 3.00%, Zn and Mg evaporate during hot stamping, and MgO and ZnO that lower the adhesiveness are formed on the surface, so that the adhesiveness is lowered. Therefore, the Si content is set to 3.00% or less.
[0024]
Ca: 0.05 to 3.00%
　Ca is an element that enhances adhesiveness when contained in the oxide film 4 together with Mg. When the Ca content is less than 0.05%, Zn and Mg evaporate during hot stamping, and MgO and ZnO that lower the adhesiveness are formed on the surface, so that the adhesiveness is lowered. Therefore, the Ca content is set to 0.05% or more.
　On the other hand, even if the Ca content exceeds 3.00%, Zn and Mg evaporate during hot stamping, and MgO and ZnO that lower the adhesiveness are formed on the surface, so that the adhesiveness is lowered. Therefore, the Ca content is set to 3.00% or less.
[0025]
　The plating layer 3 of the hot stamp molded body 1 according to the present embodiment basically contains the above-mentioned elements, and the balance is made of Zn and impurities.
　However, the plating layer 3 may contain Sb, Pb, Cu, Sn, Ti, Sr, Cr, Ni, and Mn in the following range in addition to the above elements. Since these elements do not necessarily have to be contained, the lower limit is 0%. The total content of these elements is preferably 5.00% or less.
[0026]
Sb: 0 to 0.50%
Pb: 0 to 0.50%
Cu: 0 to 1.00%
Sn: 0 to 1.00%
Ti: 0 to 1.00%
　Sb, Pb, Cu, Sn and Ti are , It is replaced with Zn in the plating layer 3 and forms a solid solution in the MgZn 2 phase , but if it is within a predetermined content range, it does not adversely affect the characteristics of the hot stamp molded body 1. Therefore, these elements may be contained in the plating layer 3. However, when the content of each element is excessive, oxides of these elements are precipitated when the hot stamp is heated, and the surface properties of the hot stamp molded product 1 tend to deteriorate and the adhesiveness tends to decrease. Further, when the contents of Pb and Sn are excessive, the weldability and the LME resistance are also deteriorated.
　Therefore, the contents of Sb and Pb are 0.50% or less, respectively, and the contents of Cu, Sn, and Ti are 1.00% or less, respectively. The content of Sb and Pb is preferably 0.20% or less, and the content of Cu, Sn and Ti is preferably 0.80% or less, more preferably 0.50% or less.
[0027]
Sr: 0 to 0.50%
　Sr is an element effective for suppressing the formation of top dross formed on the plating bath during production. Further, Sr is an element that suppresses color change of the plated steel sheet after the heat treatment because it suppresses atmospheric oxidation during the heat treatment of the hot stamp. Therefore, Sr may be contained. In order to obtain the above effects, the Sr content is preferably 0.05% or more.
　On the other hand, when the content of Sr is excessive, the swelling width of the coating film and the flow rust are adversely affected in the corrosion test. Therefore, the Sr content is set to 0.50% or less. The Sr content is preferably 0.30% or less, more preferably 0.10% or less.
[0028]
Cr: 0 to 1.00%
Ni: 0 to 1.00%
Mn: 0 to 1.00%
　In a plated steel sheet, Cr, Ni and Mn are concentrated near the interface between the plating layer and the base material and plated. It has the effect of eliminating spangles on the layer surface. Therefore, one or more selected from Cr, Ni and Mn may be contained in the plating layer. When these effects are obtained, the contents of Cr, Ni and Mn are preferably 0.01% or more, respectively.
　On the other hand, when the content of these elements is excessive, the swelling width of the coating film and the flow rust increase, and the corrosion resistance tends to deteriorate. Therefore, the contents of Cr, Ni and Mn are set to 1.00% or less, respectively. The contents of Cr, Ni and Mn are preferably 0.50% or less, more preferably 0.10% or less, respectively.
[0029]
　The chemical composition of the plating layer is measured as follows.
　The average composition of the plating layer is measured by melting and peeling the plating layer and then analyzing the content of elements contained in the peeled plating layer by an inductively coupled plasma atomic emission (ICP) analysis method. The peeling of the plating layer may be performed, for example, by immersing the plating layer in 10% hydrochloric acid containing an inhibitor that suppresses corrosion of the base iron (pickling suppression inhibitor: manufactured by Asahi Chemical Co., Ltd.), and determining that the dissolution is completed when the foaming stops. ..
[0030]
　The structure of the plating layer is not limited, but includes, for example, an Fe—Al phase, a Zn—Mg phase, and a Zn—Al—Mg phase. The amount of the plating layer adhered is not limited, but is preferably 10 to 120 g / m 2 . The amount of adhesion of the plating layer can be determined from the change in weight before and after melting the plating layer at room temperature by the above method.
[0031]

[In atomic%, Mg: 20.0 to 55.0%, Ca: 0.5 to 15.0%, Zn: 0 to 15.0%, Al: 0% or more, 10.0 The balance consists of O and impurities of 5.0% or less in total.]
　The surface of a hot stamped compact obtained by hot stamping a steel material having a plating layer containing Al (of the plating layer). On the surface), an oxide mainly composed of Al 2 O 3 is formed. This oxide film reduces the adhesiveness.
　On the other hand, in the hot stamp molded body 1 according to the present embodiment, by performing plating by a method as described later to control the solidified structure, evaporation of Zn and Mg is suppressed at the time of subsequent hot stamping. At the same time, an oxide film 4 mainly composed of Ca and Mg is formed on the surface of the steel material. This oxide film has excellent adhesiveness.
　If the Mg content in the oxide film is less than 20.0%, a large amount of Al is contained in the oxide, and the adhesiveness is lowered. Further, when the Mg content is more than 55.0%, the adhesiveness between the adhesive and the oxide is rather lowered, and the adhesiveness is lowered.
　Further, if the Ca content in the oxide film is less than 0.5%, the strength of the oxide itself is lowered and the adhesiveness is lowered. Further, when the Ca content is more than 15.0%, the adhesiveness between the adhesive and the oxide is rather lowered, and the adhesiveness is lowered.
　Further, when the oxide film 4 contains more than 15.0% of Zn, the adhesiveness is greatly deteriorated. Therefore, the Zn content is set to 15.0% or less. Further, when the oxide film 4 contains 10.0% or more of Al, the adhesiveness is greatly deteriorated. Therefore, the Al content is set to less than 10.0%. Zn and Al may not be contained.
　The balance of the chemical composition of the oxide film 4 consists of O and impurities of 5.0% or less in total.
　If the impurity element is more than 5.0%, sufficient adhesiveness cannot be obtained. Examples of impurities are Fe, Si, and C.
[0032]
　FIG. 2 shows an example of a typical SEM observation image of the oxide film formed on the surface of the hot stamp molded body according to the present embodiment. As shown in FIG. 2, the oxide film 4 of the hot stamp molded product 1 according to the present embodiment is an oxide 11 mainly containing Mg and Ca, and the Al content of the oxide is less than 10.0%. be. This oxide has a short crystal diameter of 1 to 10 μm.
[0033]
　The chemical composition of the oxide film is such that the plating layer is not dissolved and only the oxide film is dissolved, for example, 20% chromium acid is used to dissolve the solution, and the solution in which the film is dissolved is analyzed by ICP to obtain the average composition of the oxide film. Obtained by measuring.
[0034]
[Amount of adhesion on one side] When the amount
　of adhesion on one side of the oxide film is 0.01 to 10 g / m 2 and the
　amount of adhesion on one side of the oxide film is less than 0.01 g / m 2 , the effect of improving the adhesiveness is sufficiently obtained. I can't. On the other hand, if the amount of adhesion on one side exceeds 10 g / m 2 , cracks occur in the oxide layer when subjected to bending or the like, which also causes a decrease in adhesiveness (peeling). Therefore, the amount of adhesion on one side is set to 0.01 to 10 g / m 2 .
[0035]
　When determining the amount of adhesion on one side by the method of dissolving, seal the opposite surface and end surface with tape other than the surface to be measured, and immerse in the solution to obtain a release liquid of only the measurement surface before and after dissolution. It can be obtained from the change in weight.
[0036]

　The hot stamp molded product according to the present embodiment can obtain the effect as long as it has the above-mentioned characteristics regardless of the manufacturing method. However, a production method including the following steps is preferable because stable production can be performed.
　That is, in the hot stamp molded body according to the present embodiment,
(I) a plating step of immersing the steel material in a plating bath to obtain a plated steel material having a plating layer, and
(II) hot stamping the plated steel material after the plating step. It
is equipped with a hot stamping step, and in the
(III) plating step, in the cooling process after immersion in the plating bath, the average cooling rate of the bath temperature to 450 ° C is set to 10 ° C / sec or more, and the average cooling rate of 450 to 350 ° C is set.
It can be obtained by a manufacturing method of cooling to room temperature so that the temperature is 7 ° C./sec or less and the average cooling rate of 350 to 150 ° C. is 4 ° C./sec or less .
[0037]

[Immersion in plating bath] In the
　plating process, a steel material such as a steel plate to be a raw plate is immersed in a plating bath to form a plating layer on the surface.
　The conditions for immersion in the plating bath are not particularly limited. For example, the surface of the original plating plate is heat-reduced at 600 to 940 ° C, air-cooled with N2 gas , the temperature of the steel material reaches the bath temperature + 20 ° C, and then the plating bath with a bath temperature of 500 to 750 ° C is about 0. .Soak for 2-6 seconds.
　If the immersion time is less than 0.2 seconds, the plating layer may not be sufficiently formed. On the other hand, if the immersion time exceeds 6 seconds, the plating layer and the steel material are excessively alloyed, and a large amount of Fe is contained in the plating layer. When excess Fe is contained in the plating layer, it becomes difficult to suppress the evaporation of Zn and Mg during the heating of the hot stamp. Therefore, when the immersion time is more than 6 seconds, an oxide film having a predetermined composition cannot be obtained, and the adhesiveness of the hot stamp molded product is lowered.
　The plating bath may be set to contain Zn, Al, Mg and other elements according to the composition of the target plating layer 3. For example, any element containing Al: 30.00 to 75.00%, Mg: 4.00 to 17.00%, Si: 0.20 to 2.00%, and which is desired to be contained in the plating layer as needed. The balance is Zn and impurities.
[0038]
[Cooling]
Average cooling rate from bath temperature to 450 ° C: 10 ° C / sec or more
　In the method for manufacturing a hot stamped compact according to the present embodiment, the average temperature range up to 450 ° C after the plated steel material is pulled up from the plating bath. Cool so that the cooling rate is 10 ° C./sec or higher. By setting the average cooling rate in this temperature range to 10 ° C./sec or more, it is possible to suppress the formation of Al oxide on the surface of the plated steel material.
[0039]
Average cooling rate of 450 to 350 ° C.: 7 ° C./sec or less Following
　the above cooling, cooling is performed so that the average cooling rate in the temperature range of 450 ° C. to 350 ° C. is 7 ° C./sec or less.
　By controlling the solidification structure by lowering the cooling rate in this temperature range, the surface of the oxide film contains less Al (10 atomic% or less) and contains Mg and Ca in the subsequent hot stamping process. Is formed. As a result, the adhesiveness of the hot stamp molded product is improved.
　Further, in the case of a zinc-based plating layer, there is a concern that Zn (zinc) evaporates due to hot stamping, but in the solidified structure controlled as described above, although the detailed mechanism is not clear, an element having a high vapor pressure. Al, Zn, Ca, and Si-containing intermetallic compounds that have the effect of suppressing the evaporation of Zn and Mg are preferentially generated near the surface of the plating layer, so that during subsequent heating of the hot stamp. Evaporation of Zn and Mg can be suppressed.
[0040]
Average cooling rate of 350 to 150 ° C.: 4 ° C./sec or less Following
　the above cooling, when the average cooling rate of 350 ° C. to 150 ° C. is set to 4 ° C./sec or less, the solid solution of Al and Zn contained in the solidified structure is formed. Separation into an Al phase and a Zn phase lowers the melting point of the plating layer, and makes it easier for intermetallic compounds containing Al, Zn, Ca and Si to move to the surface of the plating layer in a molten state during hot stamp heating. .. As a result, it becomes possible to suppress the evaporation of Zn and Mg more efficiently, and it becomes possible to efficiently form an oxide film containing Mg and Ca.
　However, even if the average cooling rate of 350 ° C. to 150 ° C. is 4 ° C./sec or less, if the cooling rate in a part of the temperature range is high, a preferable metal structure cannot be obtained. Therefore, the average cooling rate of 350 ° C. to 150 ° C. is 4 ° C./sec or less, the average cooling rate of 350 ° C. to 250 ° C. is 4 ° C./sec or less, and the average cooling rate of 250 to 150 ° C. is 4 ° C./sec. It is preferably less than a second.
[0041]

　Hot stamping is performed on the plated steel material (a steel material having a base material and a plating layer formed on the surface thereof) after the plating process.
　The conditions for hot stamping are not limited, and examples thereof include a method of heating to 750 to 1200 ° C., holding for 0 to 8 minutes, and then sandwiching the plated steel sheet with a flat plate mold at a temperature of about room temperature to quench.
[0042]
　According to the above-mentioned manufacturing method, the hot stamp molded product according to the present embodiment can be obtained.
Example
[0043]
　Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
[0044]
　Tables 1 to 3 show examples disclosed in the present invention. Various Zn-Al-Mg-based plating baths were built and subjected to hot stamp heating. A steel plate having a thickness of 1.6 mm (including C: 0.2% and Mn: 1.3%) was used as the plating original plate. After cutting the original plate to 100 mm × 200 mm, plating was performed with a batch-type hot-dip plating test device manufactured in-house. The plate temperature was measured using a thermocouple spot-welded to the center of the original plating plate. Before immersion in the plating bath, the surface of the plating original plate is heat-reduced at 800 ° C. in an N 2-5% H 2 gas atmosphere in a furnace with an oxygen concentration of 20 ppm or less, and air-cooled with N 2 gas to
　raise the immersion plate temperature to +20. After reaching the temperature, the mixture was immersed in a plating bath having a bath temperature shown in Table 2 for about 3 seconds. After soaking in the plating bath, it was pulled up at a pulling speed of 20 to 200 mm / sec. 　At the time of pulling up, the amount of plating adhered was controlled by N 2 wiping gas as shown in Table 2. After pulling up the steel sheet from the plating bath, it was cooled from the plating bath temperature to room temperature under the conditions shown in Table 2. 　The produced plated steel sheet was subjected to hot stamp heating and mold quenching. As for the heating conditions, the plated steel sheet is inserted into a heating furnace at 900 ° C, and after the temperature of the plated steel sheet reaches the temperature inside the furnace of -10 ° C, it is retained for 0 to 8 minutes, and then the flat plate mold is at a temperature of about room temperature. A molded product was produced by sandwiching a plated steel sheet with a steel sheet and quenching it. 　As a result of investigation by the above-mentioned method, the chemical composition of the plating layer after hot stamping was as shown in Table 1.

　No. For 31, hot stamping was performed using a commercially available alloyed hot-dip galvanized steel sheet.
[0045]
[table 1]

[0046]
[Correction under Rule 91 19.10.2021]　
[Table 2]

[0047]

　In order to investigate the state of the oxide formed during hot stamp heating, the prepared sample was dissolved in 20% chromic acid, and the solution in which the oxide film was dissolved was analyzed by ICP to analyze the oxide. The average composition of the film was measured. Moreover, when the amount of adhesion per one side was measured from the weight change before and after dissolution, the amount of adhesion on one side of the oxide film was No. Except for 31, all were 0.01 to 10 g / m 2 .
　Table 2 shows the analysis results of the oxide film.
　Further, the sample after hot stamping was cut into 25 mm (C direction) × 15 mm (L direction), and the shape of the oxide film on the sample surface was observed using SEM. The oxide film of the hot stamped compact of the present invention was composed of Mg and Ca-containing oxides, and had a short crystal diameter of 1 to 10 μm. For example, FIG. 2 shows No. 1 in Tables 1 to 3. 10 SEM images (BSE images).
　On the other hand, FIG. 3 shows Example No. 11 (comparative example) SEM image (BSE image). No. In No. 11, coarse Al-containing oxide 12 was observed.
[0048]

　Adhesiveness was evaluated by the following method.
　Two 100 x 25 mm samples are taken from the hot-stamped plated steel sheet, and an adhesive (Penguin Cement # 1066) is applied to the plated steel sheet to have an adhesive area of ​​12.5 x 25 mm, then bonded and baked at 120 ° C for 45 minutes. A test piece for adhesiveness evaluation was prepared. The adhesive strength was measured by a tensile shear test using this sample. It was subjected to a tensile shear test with a tensile speed of 5 mm / min and a chuck distance of 112.5 mm, and the maximum stress in the obtained stress-strain curve was taken as the adhesive strength, and the higher the adhesive strength, the better the adhesiveness.
　When the adhesive strength was 30 to 25 MPa, it was designated as "AA", when it was less than 25 to 20 MPa, it was designated as "A", and when it was less than 20 to 15 MPa, it was designated as "B".
[0049]
　The results are shown in Table 3.
[0050]
[Table 3]

[0051]
　No. which is an example of the present invention. 3, 5 to 10, 17 to 20, 23 to 26, 28, 29 are excellent because an oxide film containing Mg and Ca disclosed in the present invention can be obtained on the Zn—Al—Mg based plating phase. It showed adhesiveness.
　On the other hand, in the comparative example in which the chemical composition of the plating layer was out of the range of the present invention or the production method was not preferable, a preferable oxide film could not be obtained and the adhesiveness was inferior.
　In addition, the adhesiveness was inferior even in the comparative example using a commercially available alloyed hot-dip galvanized steel sheet.
Code description
[0052]
　　1 Hot stamp molded body
　　2 Base material
　　3 Plating layer
　　4 Oxide film
　　11 Mg, Ca-containing oxide
　　12 Al-containing oxide
The scope of the claims
[Claim 1]
　It comprises a base material made of steel,
　a plating layer formed on the surface of the base material,
　and an oxide film formed on the surface of the
plating layer, and the chemical composition of the plating layer is 　Al
　in mass%.
: 20.00 to 45.00%,
　Fe: 10.00 to 45.00%,
　Mg: 4.50 to 15.00%,
　Si: 0.10 to 3.00%,
　Ca: 0.05 to 3 .00%,
　Sb: 0 to 0.50%,
　Pb: 0 to 0.50%,
　Cu: 0 to 1.00%,
　Sn: 0 to 1.00%,
　Ti: 0 to 1.00%,
　Sr : 0 to 0.50%,
　Cr: 0 to 1.00%,
　Ni: 0 to 1.00%,
　Mn: 0 to 1.00%,
the balance is Zn and impurities, and the
　oxide film The chemical composition of is atomic%,
　Mg: 20.0 to 55.0%,
　Ca: 0.5 to 15.0%,
　Zn: 0 to 15.0%,
　Al: 0% or more and less than 10.0%
, the balance is O and impurities of 5.0% or less in total, and the
　amount of one-sided adhesion of the oxide film is 0.01 to 10 g / m 2 . ,
A hot stamped body characterized by that.
[Claim 2]
　The chemical composition of the plating layer is characterized by containing one or two types of
　Al: 25.00 to 35.00% and
　Mg: 6.00 to 10.00% in mass%. The hot stamp molded body according to claim 1.

[Claim 3]
The hot stamp molded product according to claim 1 or 2, 　wherein the chemical composition of the oxide film is atomic% and contains
　Mg: 35.0 to 55.0% .