0001]The present invention relates to a hot stamping molded article.
BACKGROUND
[0002]Structural member (molded article) used in an automobile or the like, in order to improve both the strength and dimensional accuracy, it may be produced by hot stamping (hot press). In producing a molded body by a hot stamp, a hot stamp steel materials Ac 3 heated above points, quenched while pressing a hot stamping steel in the mold. That is, in the manufacture, perform the press working and quenching at the same time. According to hot stamping, high dimensional accuracy, and it is possible to produce shaped bodies of high strength.
[0003]
　On the other hand, moldings produced by hot stamping, because it is processed at high temperatures, the iron scale is formed on the surface. Accordingly, by using the plated steel plate as a steel sheet for hot stamping, (see Patent Documents 1 3) to suppress the formation of iron scale, yet the technique for improving the corrosion resistance of the molded article has been proposed. For example, there have been disclosed for hot pressing plated steel sheet Zn plating layer is formed, also the mobile member for coated steel sheet Al plating layer was formed on the patent document 2 is disclosed in Patent Document 1. Further, Patent Document 3, the hot-press Zn-plated steel sheet which various elements such as Mn is added to the plating layer of the Zn-plated steel sheet is disclosed. However, these plated steel sheets, there is a problem shown below.
[0004]
　In Patent Document 1 technology, since Zn remains on the surface layer of the molded body after the hot stamping, it can be expected high sacrificial protection effect. However, in the technique of Patent Document 1, since Zn is plated steel sheet in a molten state are hot pressing, hot-dip Zn during hot pressing may enter the base material of the plated steel sheet, cracks inside the base material there is a risk of causing. This crack is referred to as a liquid metal embrittlement cracks (Liquid Metal Embrittlement, sometimes hereinafter referred to as "LME"). Due to the LME, fatigue properties of the molded body is deteriorated.
[0005]
　In the present situation, in order to avoid the occurrence of LME, it is necessary to control the heating conditions during processing of the coated steel sheet as appropriate. Specifically, all of the molten Zn is diffused into the base material of the plated steel sheet, and a method of heating until Fe-Zn solid solution is employed. However, in order to carry out these methods, it is necessary to heat the long plated steel sheet, as a result productivity is lowered.
[0006]
　The technique of Patent Document 2, since it is used the melting point is higher Al than Zn as a plating layer, a possibility that the molten metal as in Patent Document 1 penetrates the base material of the plating steel is low. Therefore, according to the technique of Patent Document 2, provides excellent resistance to LME resistance, the molded body is expected to be obtained having excellent fatigue characteristics and thus after hot stamping. However, the molded article Al plating layer is formed, there is a problem that it is difficult to form a phosphate film during phosphating is performed before application of automotive parts. In other words, shaped bodies according to the technique of Patent Document 2 has a problem in that phosphating property is not sufficiently obtained.
[0007]
　In the technique of Patent Document 3, by reforming the surface layer (oxide film) of the hot stamping material, thereby improving the weldability. However, in the technique of Patent Document 3, there is a risk that LME fatigue characteristics of a hot stamping molded article can not be obtained sufficiently occur. Further, in the technique of Patent Document 3, an element to be added to the plating layer, which may lower the phosphating properties.
CITATION
Patent Document
[0008]
Patent Document 1: Japanese Patent 2003-73774 JP
Patent Document 2: Japanese Patent 2003-49256 JP
Patent Document 3: Japanese Patent 2005-113233 JP
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　The present invention was made in view of the above circumstances, the fatigue characteristics, and to provide a phosphate treatment properties, coating adhesion and weldability superior hot stamp molding.
Means for Solving the Problems
[0010]
　The gist of the present invention is as follows.
[0011]
(1) hot stamping molded body according to one embodiment of the present invention includes: a base material; a plating layer; wherein the plating layer comprises, in order toward the surface side from the base material side, and the interfacial layer, the intermediate layer When including an oxide layer, wherein the interfacial layer, tissue total 99 area% or more of the alpha iron, Fe 3 Al, and include FeAl, average Al content is 8.0 mass% or more 32.5 mass % or less in the range, the average Zn content is limited to less Zn content super 5 wt% of the base material, the remainder of the chemical component comprises Fe and impurities, and an average film thickness of 1.0μm or more There, the intermediate layer, the tissue is total 99 area% or more of Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 wherein the average Al content is 30 to 50 mass%, average Zn content the amount is 10 to 40 mass%, the balance of chemical components including Fe and impurities Seen, and the average thickness is at least 5.0 .mu.m, the oxide layer has an average thickness is 0.1 ~ 3.0 [mu] m.
(2) In the hot stamping molded article according to the above (1), wherein the interface layer has an average thickness may be 1.0 ~ 10.0 [mu] m.
(3) above (1) or (2) by hot stamping molded article according to the total weight per unit area of Al and Zn of the plating layer is 20 g / m 2 or more 100 g / m 2 even less good.
(4) In the hot stamping molded article according to any one of the above (1) to (3), wherein the plating layer further containing an average of 0 mass percent and 10.0 mass% or less of Si, the middle layer in the Fe (Al, Zn) 2 and the Fe 2 (Al, Zn) 5 0 out of ~ 50 area percent, Fe (Al, Si) may be substituted in.
Effect of the invention
[0012]
　Hot stamping molded body according to the present invention, an alloy form of the plating layer, Al, Zn amount in the particular layer in the coating layer, and the thickness of the oxide formed as the outermost surface layer of the plating layer by performing a respective improve upon there. As a result, according to the hot stamping material according to the present invention, the fatigue characteristics improving the molded bodies based on suppression of LME generation, improvement of phosphating of the molded body, and the improvement of coating adhesion due to this and , it is possible to achieve all the improvement of welding of the molded body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013]
[1] was hot V bending immediately after heating the Al-Zn-based plating steel under the conditions of Example 1, which is an example of a cross-sectional SEM image showing a processing portion of the molded body.
[Figure 2] was hot V bending immediately after heating the Zn-based plating steel under the conditions of Example 1, which is an example of a cross-sectional SEM image showing a processing portion of the molded body.
[3] The Al-based plated steel material was hot V bending immediately after heating under the conditions of Example 1, which is an example of a cross-sectional SEM image showing a processing portion of the molded body.
[Figure 4] Al-Zn-based plating steel, when quenched while machining a flat mold having a water cooling jacket immediately after heating under the conditions of Example 1 were subjected to subsequent phosphating, moldings it is an example of a SEM image showing the surface of the (secondary electron image).
[5] The Zn-based plating steel, when quenched while machining a flat mold having a water cooling jacket immediately after heating under the conditions of Example 1 were subjected to subsequent phosphate treatment, the surface of the molded body the is an example of a SEM image (secondary electron image) showing.
[Figure 6] Al-based plated steel material, when the example was processed in a flat plate mold having a water cooling jacket was quenched while immediately after heating at 1 conditions, were subjected to subsequent phosphate treatment, the surface of the molded body the is an example of a SEM image (secondary electron image) showing.
7 is a cross-sectional view in the vicinity of the surface of the hot stamping molded body according to the present embodiment.
8 is a schematic diagram of Al concentration and the Zn concentration in the vicinity of the surface of the hot stamp molded body according to the present embodiment.
DESCRIPTION OF THE INVENTION
[0014]
　Hereinafter, an embodiment of a hot stamping molded article according to the present invention in detail. The unit "%" relates to the chemical components of the hot stamping molded body according to the present embodiment is intended to mean in particular "mass%" unless otherwise specified. Further, in the present embodiment, the hot stamping material, means one obtained by performing hot stamping (hot pressing) to the hot stamping plated steel. Hereinafter simply hot stamping member referred to as "molded body", the hot stamping plated steel may be simply referred to as "steel" or "plating steel".
[0015]
　The present inventors have studied the fatigue characteristic (resistance LME resistance) and phosphating of hot stamping molded article (Al-Zn-based plating steel, Zn-plated steel and Al-based plated steel material). As a result, the present inventors found that the plating layer of the hot stamping molded article, in the order toward the surface side from the base material side includes an interfacial layer, an intermediate layer, an oxide layer, the interface layer is tissue There total 99% or more by area of alpha iron, Fe 3 Al, and include FeAl, Al content is decreased as 8.0 is the mass% or more in the range of 32.5 mass% or less and closer to the base material, the average Zn content is limited to 5 wt% or less, the remainder of the chemical composition includes Fe and impurities, and the average thickness is not less 1.0μm or more, the intermediate layer, the tissue is total 99 area% or more of Fe ( Al, Zn) 2 and Fe 2 (Al, Zn) 5 comprises from 30 to 50 mass% average Al content is 10 to 40 mass% average Zn content, the remainder of the chemical composition of Fe in and includes impurities, and the average thickness is more than 5.0μm Ri, the oxide layer, when the average film thickness is 0.1μm or more 3.0μm or less, to obtain a knowledge of the fatigue properties and phosphating of hot stamping member are both good, and. In the present specification, the average film thickness is intended to mean the average of the maximum film thickness and the minimum thickness of the layer of interest (film).
[0016]

　will be described below hot stamping molded body according to the present embodiment. Hot stamping molding 1 according to this embodiment, as shown in FIG. 7, includes a base member 10 and the plating layer 20.
[0017]
[Components of the base material]
　below, the base material of the hot stamping molded body according to the present embodiment, the preferred component is described. Is the subject of a hot stamping molded article according to the present embodiment, resistance to LME resistance and phosphating property improvements are achieved by the structure of the plating layer. Accordingly, the base material of the hot stamping molded body according to the present embodiment is not particularly limited. However, if the components of the base material is in the range described below, in addition to anti-LME resistance and phosphating properties, molded article having suitable mechanical properties. Hereinafter, the unit of content of the alloy elements contained in the base material "%" means "% by mass".
[0018]
: (C preferably 0.05 to
　0.40%) if more than 0.05% carbon (C) contained in the base material, the strength of the hot stamping molded article is enhanced. On the other hand, if the C content of the base material is 0.40 percent, there may be insufficient toughness of the base material of the shaped body. Therefore, the C content of the base metal may be from 0.05 to 0.40%. A further preferred lower limit of the C content of the base metal is 0.10%, and even more preferably the lower limit is 0.13%. A further preferred upper limit of the C content of the base metal is 0.35%.
[0019]
(Si: preferably 0.5% or less)
　silicon (Si) has the effect of deoxidizing the steel. However, decreases the wettability of the steel material for plating and the Si content is increased, it may be impossible plating normally. Therefore, the Si content of the base metal may be 0.5% or less. A further preferred upper limit of the Si content of the base metal is 0.3%, even more preferred upper limit of the Si content of the base metal is 0.2%. A further preferred lower limit of the Si content of the base material can be determined according to the deoxidation level required, for example, 0.05%.
[0020]
(Mn: preferably from 0.5 to
　2.5% is) if manganese of more than 0.5% (Mn) is contained in the base material, hardenability of the base material of the hot stamping before the steel is increased, after hot stamping the strength of the base material of the molded article is enhanced. On the other hand, when the Mn content of the base metal and 2.5 percent, the effect is saturated. Therefore, the Mn content of the base metal may be from 0.5 to 2.5%. A further preferred lower limit of the Mn content of the base metal is 0.6%, even more preferably the lower limit is 0.7%. A further preferred upper limit of the Mn content of the base metal is 2.4%, even more preferably the lower limit is 2.3%.
[0021]
(P: preferably 0.03% or less)
　phosphorus (P) is an impurity contained in steel. P contained in the base material may be segregated in grain boundaries of the base metal reduces the toughness of the base material of the shaped body, reducing the delayed fracture resistance of the base material. Therefore, the P content of the base metal may be 0.03% or less. P content of the base metal is preferably as small as possible.
[0022]
: (S preferably 0.01% or less is)
　an impurity sulfur (S) is contained in the steel. S contained in the base metal reduces the toughness of the base material of the shaped body to form a sulfide, it may decrease the resistance to delayed fracture of the matrix. Therefore, S content of the base material may be 0.01% or less. S content of the base metal is preferably as small as possible.
[0023]
(Sol. Al: preferably 0.10% or less is)
　When the term "Al content" is used in reference to the base material of the molded body according to the present embodiment, sol of this term in the matrix. It means the content of Al (acid soluble Al). Aluminum (Al) is generally used in deoxidation purposes of steel. However, if the Al content is high, Ac hot stamping before the steel 3 to rise point, the heating temperature required for hardening of the steel during hot stamping is increased, the hot stamp manufacturing is undesirable. Therefore, Al content of the base material may be 0.10% or less. A further preferred upper limit of the Al content in the base metal is 0.05%. A further preferred lower limit of the Al content in the base metal is 0.01%.
[0024]
: (N preferably 0.01% or less is)
　an impurity nitrogen (N) is contained in the steel. N contained in the base material may decrease the toughness of the base material of the shaped body to form a nitride. Further, N included in the base material, if in Hahazai is B is contained in order to improve the hardenability of the hot stamping before the steel to reduce the solid solution B content in combination with B, hardenability of B it may decrease the improving effect. Therefore, the N content of the base metal may be 0.01% or less. N content of the base metal is preferably as small as possible.
[0025]
　Base material of a hot stamping molded article of the present embodiment may further contain one or more selected from the group consisting of B and Ti.
[0026]
(B: preferably 0 ~ 0.0050%)
　B, so has the function of increasing the hardenability of the steel, increasing the strength of the base material of the molded body after the hot stamping. However, if Sugire large, the B content of the base metal, this effect is saturated. Therefore, the B content of the base metal may be from 0 to 0.0050%. A further preferred lower limit of the B content of the base metal is 0.0001%.
[0027]
: (Ti preferably 0 ~ 0.10%)
　Ti contained in the base material is combined with N contained in the base material to form a nitride. If this is the Ti and N to bind to, is suppressed binding to N of the matrix B and the base material, it is possible to suppress a decrease of the hardenability of the base material by the BN formation. Furthermore, Ti contained in the base material, by its pinning effect, the austenite grain size finer during heating in the hot stamping, thereby having the effect of increasing the toughness and the like of the molded article. However, the effect is saturated if Sugire large, the Ti content of the base material, further, the toughness of the base material of the molded body Ti nitrides are excessively precipitated may be reduced. Therefore, the Ti content of the base metal may be from 0 to 0.10%. Preferred lower limit of the Ti content of the base metal is 0.01%.
[0028]
　Base material constituting the hot stamping molded article of the present embodiment may further contain one or more selected from the group consisting of Cr and Mo.
[0029]
: (Cr preferably 0 ~ 0.5%)
　Cr contained in the base material, enhance the hardenability of the base material of the hot stamping preceding steel. However, if Sugire large, the Cr content of the base metal, Cr carbide is formed. The Cr carbide is hardly dissolved during the heating of the hot stamping, hinder the progress of austenitizing, it may decrease the hardenability. Therefore, the Cr content of the base metal may be from 0 to 0.5%. A further preferred lower limit of the Cr content of the base metal is 0.1%.
[0030]
: (Mo preferably 0 ~ 0.50%)
　Mo contained in the base material, enhance the hardenability of the base material of the hot stamping preceding steel. However, if Sugire large, the Mo content of the base material, the effect is saturated. Therefore, the Mo content of the base metal may be from 0 to 0.50%. A further preferred lower limit of the Mo content of the base metal is 0.05%.
[0031]
　Base material constituting the hot stamping molded article of the present embodiment may further contain one or more selected from the group consisting of Nb and Ni.
[0032]
(Nb: preferably 0 ~ 0.10%)
　Nb contained in the base material, to form a carbide, the crystal grains of the base material is miniaturized during hot stamping, enhance the toughness of the molded article. However, if Sugire large, Nb content of the base material, the effect is saturated. Furthermore, Sugire large, Nb content of the base metal, hardenability of the base material may decrease. Therefore, the Nb content may be from 0 to 0.10%. A further preferred lower limit of the Nb content of the base metal is 0.02%.
[0033]
: (Ni preferably 0 ~ 1.0%)
　Ni contained in the base material, enhance the toughness of the base material of the shaped body. Ni of the base material is further upon heating in a hot stamp, suppressing embrittlement due to the presence of the molten Zn. However, if Sugire large, the Ni content of the base material, these effects are saturated. Therefore, the Ni content of the base metal may be 0 to 1.0%. A further preferred lower limit of the Ni content of the base metal is 0.1%.
[0034]
　The remainder of the chemical composition of the base material constituting the hot stamping molded article of the present embodiment is composed of Fe and impurities. In the present specification, the impurity, when the industrial production of moldings, which may be included in the ore or scrap as a raw material, or is one which can be mixed due to the manufacturing environment.
[0035]
[Plating Layer]
　Next, a description will be given plating layer 20 of the hot stamping molding 1 according to this embodiment. Plating layer 20 of the molded body 1, as shown in FIG. 7, toward the surface side of the molded body 1 from the base material 10 side of the molded body 1, the interfacial layer 21, an intermediate layer 22, oxide layer 23 and, sequentially, including the.
[0036]
[Interfacial layer]
　interfacial layer is formed adjacent to the base material. Most organizations of the interface layer, alpha iron, Fe 3 Al, and composed of FeAl. That is, the interface layer of the hot stamping molded body according to the present embodiment is composed mainly of Al content is less Fe-Al alloy phase. Note that inclusions caused by impurities mixed in the plating and the like, may be included only in the interfacial layer. But we, when observed a surface layer in the cross section of the plating layer of the hot stamping, tissue total 99 area% or more of the alpha iron, Fe 3 Al, and if it contains FeAl, as described above influence of inclusions was confirmed to the effect that can be ignored. To control as the tissue interface layer described above, it is necessary that the average Al content of the surface layer with 8.0 wt% or more 32.5% by mass or less. Incidentally, Al content of the surface layer as described later is not uniform, Al content of the surface layer nears the base material is reduced.
[0037]
　In the interface layer, Zn is present in a state of solid solution in Fe-Al alloy phase described above. However, according to the place which we have knowledge, the interface layer of the molded body according to the present embodiment is Zn is hardly dissolved, the average Zn content of the surface layer is not more than 5 wt%. The presence of the interfacial layer, liquid metal embrittlement cracks of the (LME) can be suppressed. Incidentally, there are cases Zn content of the surface layer is also not uniform, since LME long as the average Zn content of the surface layer is not more than 5 wt% is suppressed, the interface layer is greater than 5 wt% Zn it may include a region containing. Zn content of the surface layer is minimized at the interface between the interface layer and the base material. Therefore, the minimum value of the Zn content of the surface layer is a Zn content in excess of the base material.
[0038]
　The configuration of the interface layer shown schematically in FIG. As described above, Al content in the interfacial layer 21 is not uniform. Al content at the interface between the base material 10 and the interface layer 21 is the same as the Al content of the base member 10. Increasing distance from the interface between the base material 10 and the interface layer 21, Al content is increased, tissue lowest αFe phase Al content, a small Fe content of Al in the second 3 Al phase, and Al content in the third changes at a small FeAl phase order. Zn content at the interface between the base material 10 and the interface layer 21 is the same as the Zn content of the base member 10. Zn content also, but increases as the distance from the interface between the base material 10 and the interface layer 21, the amount is kept low, if the average of the Zn content in the entire interface layer 21, does not exceed 5 wt% .
[0039]
　If the average thickness of the interfacial layer is less than 1.0 .mu.m, LME suppressing effect can not be obtained sufficiently. Therefore, there is an average thickness of the interface layer must be at least 1.0 .mu.m. If the average thickness of the interface layer was not less than 2.0μm is achieved by the effect even higher level. The lower limit of the average thickness of the interfacial layer is more preferably from 5.0 .mu.m, 6.0 .mu.m or 7.0 .mu.m,. Since it is not necessary to define an average film upper limit of the thickness of the interface layer, the interface layer having an average film thickness is more than 15.0μm may degrade the performance of the corrosion resistance and the like, is not preferred. Therefore, the upper limit of the average thickness of the interface layer is preferably 15.0 .mu.m, more preferably from 10.0 [mu] m, 9.0 .mu.m or 8.0 .mu.m,.
[0040]
[Intermediate layer]
　The intermediate layer 22, Fe, a layer containing Al, and Zn, is formed on the interfacial layer 21. Most organizations of the intermediate layer, Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 composed. Fe (Al, Zn) 2 A, FeAl a kind of FeAl intermetallic compound 2 a part of Al in is the phase that has been replaced with Zn, Fe 2 (Al, Zn) 5 The , Fe is a kind of Fe-Al intermetallic compound 2 Al 5 some of Al in is the phase that has been replaced with Zn. Incidentally, like inclusions caused by mixed in plating impurities, it may be included only in the intermediate layer. However inventors have found that when observing the intermediate layer in the cross section of the plating layer of the hot stamping, tissue total 99 area% or more of Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 to include put it in, the effect of inclusions as described above was confirmed that the negligible.
[0041]
　In the intermediate layer, the content of Al and Zn is substantially uniform. Chemical composition of the intermediate layer is a unit mass%, including an average of 30% to 50% of Al, an average of 10% to 40% of the Zn. The average Al content of the intermediate layer is above the average Al content of the surface layer.
[0042]
　The configuration of the interface layer is controlled as described above, thereby suppressing the LME at the interface layer, if imparted with excellent fatigue properties in the molded body, the average Al content of the intermediate layer is 30 mass% or more. Further, by setting those composed of mainly Zn oxide oxide layer, to impart an excellent phosphating properties in the molded body, the average Al content of the intermediate layer is 50 wt% or less. That is, when the average Al content of the intermediate layer is outside the range of 30 to 50 wt%, the most likely structure of the interfacial layer or oxide layer is inappropriate. The lower limit of the average Al content of the surface layer is preferably 32 mass% or 35 mass%, in this case, it is possible to more reliably express LME suppressing effect of interface layer. Further, preferred upper limit of the average Al content of the surface layer is 50 wt% or 45 wt%, in this case, can be further reliably improved phosphating of oxide layer.
[0043]
　The oxide layer of the shaped body mainly as being composed of Zn oxide, to impart excellent phosphating properties in the molded body, an average Zn content in the intermediate layer is 10 mass% or more. Further, to suppress the LME at the interface layer, if imparted with excellent fatigue properties in the molded body, an average Zn content in the intermediate layer is 30 mass% or less. That is, when the average Zn content of the intermediate layer is outside the range of 10 to 40 wt%, the most likely structure of the interfacial layer or oxide layer is inappropriate. The preferable lower limit value of the average Zn content in the intermediate layer is 12 wt% or 13 wt%, in this case, can be further reliably improved phosphating of oxide layer. Preferred upper limit of the average Zn content in the intermediate layer is 28 wt% or 25 wt%, in this case, it is possible to more reliably express LME suppressing effect of interface layer.
[0044]
　Thickness of the intermediate layer does not directly affect the phosphating resistance and LME of moldings. However, when the thickness of the intermediate layer is small, the performance of the corrosion resistance of the molded article is lowered, the thickness of the intermediate layer is preferably set to more than 5.0 .mu.m. Further, the film thickness of the intermediate layer is excessively large, the production cost is high, there is a further HS heating time becomes longer concerns. Therefore, the thickness of the intermediate layer is less desirable 30.0.
[0045]
[Oxide layer]
　Further, the molded surface side of the intermediate layer, as the outermost surface layer of the molded article, an oxide layer 23 mainly composed of Zn oxide is formed. Oxide layer 23 is a heating process in producing the hot stamping material, plating the hot stamping plated steel material is that generated by oxidation. The oxide layer, enhancing the phosphating of hot stamping molding. To obtain the effect of improving the phosphating property and coating adhesion, it is necessary that the average thickness of the oxide layer and over 0.1 [mu] m. However, when the oxide layer is too thick, since an adverse effect on the corrosion resistance of the molded product and welding, etc., the average thickness of the oxide layer is set to 3.0μm or less. In the case where the average thickness of the oxide layer is 2.0μm or less, because the performance such as corrosion resistance and weldability of the molded body is exhibited at a high level, preferably.
[0046]
　Interfacial layer, an intermediate layer, and the oxide layer state can be identified by the following means.
　Al content of the surface layer is cut perpendicular the compact to the surface, polishing the cross section, is obtained by analyzing the Al content distribution in a region including the interface layer in the analyzer of EPMA or the like in this section . The average Zn content of the surface layer, the average Al content and an average Zn content in the intermediate layer, and an average Si content of the plating layer is obtained on the basis of the density distribution obtained by the above method.
　Metal structure of the interfacial layer and the intermediate layer is obtained by crystal structure analysis by TEM or the like.
　Interface layer, the thickness of the intermediate layer, and the oxide layer, the enlarged photograph of the aforementioned cross-section taken with an electron microscope, obtained by this enlarged photograph image analysis.
　Note that the structure of the plating layer of the molded body according to the present embodiment is not substantially uniform along a direction parallel to the surface of the molded body. In particular, the interface layer, an intermediate layer, and the thickness of the oxide layer, often differ in an area which is not processed and the machining area. Thus, above-described analysis must be carried out in a region which is not processed in the molded body. State of the plating layer in the area which is not processed is within the above range moldings, are considered to be molded body according to the present embodiment.
[0047]
　Having the configuration shown above, the hot stamp molded body according to the present embodiment, an alloy form of the interface layer and the intermediate layer constituting the plating layer, Al content and Zn content of the surface layer and the intermediate layer, and the interface layer It is performed intermediate layer, and an improvement on the film thickness of the oxide layer. As a result, according to the hot stamping material according to the present embodiment, it is possible to achieve both improved fatigue properties of the molded bodies based on suppression of LME generation, and a phosphoric improved salt treatment properties.
[0048]
　Having described the present embodiment, the present invention is not limited to the above embodiment, in a range that does not depart from the spirit of the invention, it is possible to make various changes.
[0049]
　For example, the plating layer, the total amount of Al and Zn in the plating layer is 20 g / m 2 or more 100 g / m 2 is preferably formed so as to be less. The total amount of Al and Zn in the plating layer 20 g / m 2 by the above, interfacial layers described above, an intermediate layer, and that further enhance the effect of oxide layer having (fatigue properties and phosphating property) it can. On the other hand, the total amount of 100 g / m 2 by mass or less, to suppress the raw material costs of the molded body, it is possible to reduce manufacturing cost, it can be further enhanced weldability of the hot stamping molding. Still further preferred lower limit of the total amount of Al and Zn in the plating layer is 30 g / m 2 is. A further preferred upper limit of the total amount of Al and Zn in the plating layer is 90 g / m 2 is.
[0050]
　The total amount of Al and Zn contained in the plated layer, a hot stamp compact was dissolved in hydrochloric acid, it can be measured by inducing lysates coupled plasma atomic emission spectrometry (ICP analysis). By using this method, it is possible to determine the amount of Al and Zn separately. When dissolving the plated steel material before hot stamping heated in order to dissolve only the plating layer, it is common to add suppressing inhibitor dissolution of Fe in the base material in hydrochloric acid. However, since the plating layer of the hot stamping molded article contains a Fe, in the above method, not sufficiently soluble plating layer of a hot stamping molded article, or the dissolution rate is very slow. Therefore, the plating in the Al and Zn content of the molded body when obtaining by ICP analysis using hydrochloric acid without inhibitor, the method of dissolving the plated layer at a liquid temperature of 40 ~ 50 ° C. are suitable. In order after dissolution to check whether there are no remaining melt of plating components such as Al and Zn, it is desirable to composition analysis of the surface of the hot stamping body after dissolution in EPMA. Above-described analysis must be carried out in a region which is not processed in the molded body.
[0051]
　Furthermore, the plating layer preferably contains an average 0 mass percent and 10.0 mass% of Si. The average Si content in the coating layer by 0 mass percent, it is possible to enhance the adhesion between the base material and the plated layer. On the other hand, the average Si content by 10.0 mass% or less, it is possible to prevent deterioration of the performance of corrosion resistance and weldability and the like of the hot stamping molding. A further preferred lower limit of the average Si content of the plating layer is 0.1 wt% or 0.3 wt%. A further preferred upper limit of the average Si content of the plating layer is 8.0 wt%. However, since the plating layer having excellent characteristics is hot stamp molded body according to the present embodiment, even when containing no Si, the lower limit of the average Si content of the plating layer is 0 wt%.
[0052]
　If the plating layer comprises an average 0 mass percent and 10.0 mass% of Si, structure of the intermediate layer of the phase change. As described above, if the plating layer does not contain Si, intermediate layers total 99 area% or more Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 including a plating layer is an average 0 mass If containing percent 10.0 wt% of Si, Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 is part of, is replaced with Fe (Al, Si). The Fe (Al, Si), a phase in which a part of Al in the FeAl is replaced with Si. If the average Si content of the plating layer to produce a hot stamping molded article according to the present embodiment as a 10.0% by weight, the amount of Fe (Al, Si) in the intermediate layer is about 50 area%. Therefore, if the plating layer comprises an average 0 mass percent and 10.0 mass% of Si, the intermediate layer is a total of 99 area% or more of Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 and Fe (Al includes Si) and the content of Fe (Al, Si) is 0-50% by area.
[0053]
　Incidentally, when the amount of Si is small, Si is Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 dissolved in the configuration of the intermediate layer does not change. According to a survey by the present inventors, when the average Si content of the plating layer is from 0 to 0.1 wt%, Fe (Al, Si) is estimated not to produce the intermediate layer. Further, according to the investigation of the present inventors, even when the plating layer comprises an average 0 mass percent and 10.0 mass% of Si, the phase structure of the interfacial layer is estimated unchanged. Therefore, even when the plating layer comprises an average 0 mass percent and 10.0 mass% of Si, the interface layer is total 99 area% or more alpha iron, Fe 3 include Al, and FeAl.
[0054]

　Next, a manufacturing method of hot stamping molded body according to the present embodiment. Method for producing a hot stamping of the present embodiment includes a step of producing a hot stamping plated steel and the step of hot stamping the hot stamping plated steel. Process for manufacturing a hot stamping plated steel, includes a step of producing a preform of the hot stamping plated steel, and forming the Al-Zn plating layer on the base material of the hot stamping plated steel. Method for producing a hot stamp molded body according to the present embodiment may optionally contain a rust oil film forming step and blanking process. It will be described in detail below each step.
[0055]
[Base material manufacturing process]
　plating steel is the material of the hot stamping member comprises a base material and a plating layer. The preform manufacturing process, to produce a preform of the hot stamping plated steel. For example, to produce a molten steel having the same chemical composition as the chemical composition of the base metal of a hot stamping molded article according to the present embodiment illustrated above, by using the molten steel, to produce a slab by casting. Or, by using the molten steel prepared as described above, it may be produced an ingot by ingot-making method. Then, by a slab or ingot is hot rolled, the base material of the hot stamping plated steel (hot-rolled sheet) is obtained. If necessary, subjected to pickling process on the hot-rolled plate, cold rolled steel sheet obtained by performing cold rolling with respect to hot-rolled sheet after pickling of the hot stamping plated steel base it may be used as the wood.
[0056]
[Plating process]
　The plating process, to form a Al-Zn plating layer on the base material of plating steel for the hot stamping, to produce a hot stamping plated steel.
[0057]
　The plating process, the Al content in the plating bath is 40 to 70 mass%, and the Zn content is 30 to 60 mass%. Such a plating bath composition to form a plating of hot stamping plated steel, and by hot stamping under conditions below the hot stamping plated steel, the structure of the plating layer of the hot stamping of above it can be so.
[0058]
　Incidentally, the Al content of the plating bath (the concentration) and Zn content (concentration) is substantially the same as the Al content of the plating layer of the hot stamping plated steel (concentration) and Zn content (concentration) but the average Al content of the plating layer of the hot stamping member (concentration) and the average Zn content (concentration) is lower than the Al content of the plating bath (concentration) and Zn content (concentration). Alloying occurring between the Al and Zn and Fe in the base material of the plating layer during the hot stamping is because Fe concentration in the coating layer is increased.
[0059]
　Hereinafter, the plating layer of the hot stamping plated steel, may be referred to as non-alloyed plating layer. The average Al content and an average Zn content of the non-alloyed plating layer is a non-alloyed plating layer, after dissolving in hydrochloric acid corrosion inhibitor (inhibitor) containing, analyzed by inductively coupled plasma emission spectroscopy It can be measured by. Further, in order to enhance the adhesion between the base material and the non-alloyed plating layer of the hot stamping plated steel, the Si from 0.1 to 15.0 mass% in the non-alloyed plating layer of the hot stamping plated steel it is preferable to further contain. Si content of the non-alloyed plating layer, since the Fe in the plating layer when alloying the plating and base material are diffused and decreased. Therefore, when the Si content of the non-alloyed plating layer is 0 to 15 mass%, the Si content of alloyed plated layer is 0 to 10 mass%.
[0060]
　Method of forming a non-alloyed plating layer, as long as the average Al content and average Zn content of the non-alloyed plating layer is controlled as follows, may be a hot-dip plating process, spray coating process, deposition plating treatment or the like may be any other process. For example, when forming a non-alloyed plating layer by melt plating, the plating treatment step, immersing the base material of the hot stamping plated steel, Al, the hot dipping bath contains Zn and impurities, including optionally further Si and a step of, and a step of pulling up the base material of the hot stamping plated steel material plated metal is deposited from a plating bath. When forming a non-alloyed plating layer by any other process, the chemical composition of non-alloyed plating layer obtained is such that the range described above, may be performed a plating process according to a conventional method.
[0061]
　Incidentally, as described above, in the hot stamping material, plated layer, with respect to the base material, the total weight per unit area of Al and Zn in the plating layer is 20 g / m 2 or more 100 g / m 2 or less, formation it is preferable to have been. To ensure total weight per unit area, in this step, the total weight per unit area of Al and Zn in the plating layer at the time of pulling up the base material of the hot stamping plated steel from the plating bath, 20g / m 2 or more 100 g / m 2 it is is important to less. Incidentally, the total weight per unit area of Al and Zn contained in the plated layer by oxidation and evaporation decreases slightly during alloying. In the present process, the pulling speed and steel from the plating bath, by appropriately adjusting the flow rate of wiping gases can be useful to meet the total amount.
[0062]
　Hot stamping plated steel material produced by the method described above, comprises a base material and a non-alloyed plating layer, and the non-alloyed plating layer of 40.0 to 70.0 wt% Al, 30.0 ~ including 60.0 mass% of Zn, and from 0 to 15.0 mass% Si. The hot stamping plated steel, when the hot stamping under conditions to be described later, hot stamping molded body according to the present embodiment is obtained. It will be described in detail below hot stamp conditions.
[0063]
Hot stamping step]
　In the hot stamping step, the hot stamping to the above hot stamping plated steel. Normal hot stamping is carried out by steel is heated to hot stamping temperature range (hot working temperature range), then the steel hot working, further cooling the steel. According to conventional hot stamping techniques, in order to shorten the manufacturing time, it is good that as large as possible a heating rate of the steel material. Further, since the alloying of the plating layer when heating the steel to a hot stamping temperature range progresses sufficiently, conventional hot stamping techniques, not important to control the heating condition of the steel. However, a hot stamping process for manufacturing a hot stamp member according to the present embodiment (1) the hot stamping plated steel was heated to the alloying temperature range, (2) alloying the temperature of the hot stamping plated steel material temperature held within a range, (3) heating the hot-stamping plated steel to hot stamping temperature range, (4) a hot stamping plated steel material to hot working and cooling. The present inventors have found that when raising the temperature of the hot stamping plated steel to hot stamping temperature range, substantially stopping the heating of the steel in the alloying temperature range, to be resumed after the Atsushi Nobori was above It was found to be essential for obtaining a plating layer having a configuration.
[0064]
　The hot stamping process, first, charged hot stamping plated steel material heating furnace (gas furnace, an electric furnace, an infrared furnace or the like). In a heating furnace, to heat the hot stamping plated steel to a temperature range of 500 ~ 750 ° C. (alloying temperature range), held within this temperature range 10-450 seconds. The temperature holding, Fe of the base material is diffused in the plating layer, the alloying proceeds. This alloying, non alloyed plating layer toward the surface side of the molded body from the base material side, changes to include the interface layer, an intermediate layer, and an oxide layer. The holding time with the above, is that the time the temperature of the hot stamping plated steel is in the alloying temperature range. As long as the retention time under the above conditions are satisfied, the temperature of the hot stamping plated steel, may vary within the alloying temperature range during the temperature holding.
[0065]
　Temperature maintenance of the hot stamping plated steel material, when done in less than the alloying temperature range (i.e. below 500 ° C.), the rate is very small the plating layer is alloyed, since the heating time is extended extremely, the viewpoint of productivity undesirable from. Temperature maintenance of the hot stamping plated steel material, the alloying temperature range greater, i.e. when done in 750 ° C. greater than the growth of oxide on the surface of the plating layer at this holding step is excessively promoted, obtained after HS welding of the molded article is lowered.
[0066]
　When the time for holding the temperature of the hot stamping plated steel in the alloying temperature range is less than 10 seconds, the alloying of the plating layer is not completed, the interface layer described above, an intermediate layer, and plating with an oxide layer layer can not be obtained. When the time for holding the temperature of the hot stamping plated steel in the alloying temperature range is 450 seconds greater than the growth of the oxide becomes excessive, also leading to reduction in productivity.
[0067]
　Heating condition for heating the hot stamping plated steel material to the alloying temperature range described above is not particularly limited. However, from the viewpoint of productivity, the heating time is short, it is desirable.
[0068]
　Hot stamp included in the production process of hot stamping molded body according to the present embodiment, after holding the hot stamping plated steel temperature in the alloying temperature range as described above, Ac 3 to a temperature range of point ~ 950 ° C. heating the hot stamping plated steel, followed by a hot working. At this time, plating steel temperature for hot stamp Ac 3 it is necessary to limit the time within a temperature range of point ~ 950 ° C. (oxidation temperature range) below 60 seconds. When plating steel temperature for hot stamping is in oxidation temperature range, the oxide layer of the surface layer of the plating layer is grown. If the time-plated steel temperature for hot stamping is in oxidation temperature range is greater than 60 seconds, the oxide film is excessively grown, a decrease in weldability of the shaped body is concerned. On the other hand, the rate of formation of the oxide coating is very fast, the lower limit of the time-plated steel temperature for hot stamping is in oxidation temperature range is 0 seconds greater. However, when the heating of the hot stamping plated steel was made in a non-oxidizing atmosphere such as a 100% nitrogen atmosphere, since the oxide layer is not formed, the heating of the hot stamping plated steel have to be carried out in an oxidizing atmosphere such as air atmosphere there is.
[0069]
　As long time plating steel temperature for hot stamping is in oxidation temperature range is less than 60 seconds, the heating rate and maximum conditions of the heating temperature are not particularly specified, selecting the various conditions that may perform hot stamp can.
[0070]
　Next, a hot stamping plated steel that has been removed from the furnace, to press molding using a mold. In this step, simultaneously with the press molding, quenching the steel material by the mold. The the mold and the cooling medium (e.g. water) is circulated, mold encourage heat extraction of the hot stamping plated steel, quenching is performed. Through the above steps, it is possible to produce a hot stamping molded article.
[0071]
　In the above description, it was heated hot stamping plated steel with heating furnace. However, it may be heated hot stamping plated steel by electric heating. Even in this case, the steel material was heated for a predetermined time by electrical heating, performing press molding of the steel using a mold.
[0072]
　The above is an essential step in the production process of hot stamping molded article of the present embodiment, also shown an optional step in the manufacturing method below.
[0073]
[Rustproof oil film forming step]
　rustproof oil film forming step, after the plating treatment step, and before the hot stamping process, forms a rustproof oil film by coating a rust preventive oil on the surface of the hot stamping plated steel There may be optionally included in the production process. If the time from when the hot stamping plated steel is produced until the hot stamping is carried out is long, there is a possibility that the surface of the hot stamping plated steel is oxidized. However, since the surface of the hot stamping plated steel rust oil film is formed is not easily oxidized by rustproof oil film forming step, rustproof oil film forming step, can suppress the formation of scale of the molded article. In addition, the method of forming the anti-corrosion oil film can also be used any known technique.
[0074]
[Blanking processing step]
　This step, after the rust preventive oil film forming step, and before the hot stamping process, carried out shearing and / or punching against hot stamping plated steel, specific shape the steel a step of forming a. Shear plane of the steel material after blanking working is easily oxidized. However, if it is pre-rust oil film is formed on the steel surface, rust-preventive oil spreads to some extent on the shear plane. This makes it possible to suppress oxidation of the steel material after blanking working.
[0075]
　Having described the embodiments of the present invention, the above-described embodiments are merely illustrative of the present invention. Accordingly, the present invention is not limited to the embodiment described above, in a range not departing from its spirit, it is possible to appropriately design changed.
Example
[0076]
　It will be specifically described by the inventors example the effect of the present invention. The present invention is not limited to the conditions used in the following invention examples.
Example 1
[0077]
　The present inventors have, Al-Zn-based plating layer on the base material 10, to form each a Zn-based plating layer and the Al-based plating layer. Al-Zn-based plating layer is intended to include and 55.0 wt% Al, and 45.0 wt% Zn, Zn-based plating layer is assumed to consist substantially only Zn, Al-based plating layer is substantially It consisted of Al only in manner.
[0078]
　Next, the steel material each plating layer is formed (plated steel comprised of a base material and the plating layer) was charged into the first heating furnace, and heated to 700 ° C., 120 seconds held within this temperature range did. Thereafter, the plating steel immediately charged to the second heating furnace was heated to 900 ° C., and then the steel material temperature Ac 3 so that the time which is within the range of points ~ 950 ° C. is 30 seconds, the plating steel No. It was removed from the second heating furnace. Immediately after the plating steel was taken out from the second heating furnace and subjected to hot V bending test in the plating steel using a hand press machine. After removing the steel from the furnace, the time is approximately 5 seconds before the start of machining in steel, bending was carried out at the steel temperature 800 ° C. approximately. V bending, the outer diameter of the portion to be bent has been carried out to increase the pre-bending V of about 15%. Thereafter, by cooling the steel material and hardened steel material. Cooling, cooling rate from about 800 ° C. until the martensite transformation start point (about 410 ° C.) is performed such that the 50 ° C. / sec or higher. Finally, SEM images of bending the outer portion of the working portion of the cooling after the end of the molding shooting, the grounds occurrence of LME, were evaluated fatigue properties of the molded product (anti-LME resistance).
[0079]
　Figures 1 3 is a cross-sectional photograph of the processed portion of the produced molded bodies from Al-Zn-based plating steel, Zn-plated steel and Al-based plated steel. The molded article of FIG. 1, alloyed Al-Zn-based plating layer 30 is formed on the base material 1, the molded article of FIG. 2, alloyed Zn-based plating layer 40 is formed on the base material 1, the molding of Figure 3 the body, alloyed Al-based plating layer 50 on the base material 1 is formed. The processing unit of the observed moldings, a tensile processing is made part, occurrence of LME is concerned, the V bending portion is the outer part against bending center.
[0080]
　According FIGS. 1 to 3, while the shaped body having an alloying Zn-based plating layer 40 extends crack to the inside of the base member 10, molded with alloyed Al-Zn-based plating layer 30 in the molded article having a body and alloying Al-plated layer 50, it is understood that the cracks in the interior of the base member 10 does not extend.
[0081]
　Further, removed steel is heated and the temperature maintained as above from the furnace, after forming a steel with a flat plate mold having a water cooling jacket, at the cooling rate is slower part, the martensite transformation start point (about 410 ° C.) until was hardened so that the 50 ° C. / sec or more cooling rate. Then, by adjusting the surface of the molded body was subjected to phosphating on the molding member. Finally, SEM images of the surface of the molded product was taken, the grounds around the formation of phosphate coatings were evaluated phosphating properties.
[0082]
　Figures 4 to 6, Al-Zn-based plating steel taken from the second heating furnace, the Zn-based plating steel and Al-based plated steel material was quenched with machining a flat mold having a water cooling jacket, then phosphorus when subjected to salt treatment, which is an example of a SEM image showing the surface of the molded body (secondary electron image).
[0083]
　According FIGS. 4 to 6, for the Al-Zn-based plating and Zn-based plating, whereas the entire chemical conversion crystal surface 60 (phosphate coating) is formed, for Al-based plated, surface areas not part chemical conversion crystals form, it can be seen that the so-called transparent region 70 is present.
Example 2
[0084]
　First, using a molten steel having a chemical composition shown in Table 1, it was produced slabs by continuous casting. Then, the slab to produce a hot-rolled steel and hot rolled, after further pickled hot-rolled steel was prepared cold-rolled steel by performing the cold rolling. Then, a base material using the cold rolled steel in the manufacture of hot stamping molded article (thickness 1.4 mm). Ac of the base material 3 -point was about 810 ℃.
[0085]
[Table 1]

[0086]
　Next, the thus produced preform, to form a plating using a plating bath having the composition shown in Table 2, to obtain a hot stamp steel material. Coating weight of plating, the total weight of Al and Zn are controlled to be values shown in Table 2. The steel is heated to alloy the temperature shown in Table 2, the temperature was maintained during the alloying time shown in Table 2. Then charged with steel material heating furnace Ac 3 was heated to a temperature range of point ~ 950 ° C., and then the time which the temperature of the steel is within this temperature range is set to be the retention time shown in Table 2, steel It was taken from the heating furnace.
[0087]
　Then, in order to perform hot V bending test was carried out following steps. The steel was removed from the furnace and immediately subjected to hot V bending with a hand press. Time from the start of taking out the steel from the furnace to the start of the processing of steel was set to 5 seconds. The shape of the mold was a shape such that the outer portion of the bending radius by V bending is extended about 15% at the processing end bend.
[0088]
　Further, in order to carry out phosphating evaluation test and paint adherence evaluation test it was carried out following steps. The steel was removed from the furnace and immediately subjected to hot stamped with a flat plate mold having a water cooling jacket, and then accelerated cooling. Cooling rate, to the extent martensitic transformation start point (410 ° C.), was set to be above 50 ° C. / sec cooling rate. Further, each hot stamping member, Nippon Parkerizing Co., Ltd. of surface conditioning treatment agent (trade name: Prepalene X) with the surface conditioning was performed at room temperature for 20 seconds. Then, Japan Parkerizing zinc phosphate treatment solution Co., Ltd. (trade name: PALBOND 3020) was used to perform each of the hot stamping body in phosphate processing. In phosphate treatment, the temperature of the processing solution and 43 ° C., was immersed for 120 seconds a hot stamping molded article to the processing liquid. After performing the phosphating described above, each hot stamping member, at Nippon Paint Co., Ltd. of cationic electrodeposition paint, and electrodeposition coating in the slope energizing voltage 160 V, further, the baking temperature 170 ° C. 20 minutes to baking. The average thickness of the paint after electrodeposition coating, either of the inventive example and comparative examples were also 10 [mu] m.
[0089]
[Table 2]

[0090]
　The configuration of the invention examples and comparative examples obtained by the above means was confirmed by the following method.
[0091]
　Interfacial layer of the inventive example and comparative example, the state of the intermediate layer, and the oxide layer was determined by the following means. The average Al content and an average Zn content of the surface layer, the average Al content and an average Zn content in the intermediate layer, and an average Si content of the plating layer, the shaped body was cut perpendicular to the surface of the molded body, polished cross-section, obtained by analyzing the cross-section analyzer of EPMA or the like. Metal structure of the interfacial layer and the intermediate layer was obtained by crystal structure analysis by TEM or the like. Examples satisfying the requirements of the metal structure present invention is described as "OK", an example not satisfying has been described as "NG". Interface layer, the thickness of the intermediate layer, and the oxide layer, the enlarged photograph of the aforementioned cross-section taken with an electron microscope, were obtained by this enlarged photograph image analysis. Above-described analysis was carried out in a region which is not processed in the molded body.
[0092]
　The total weight of Al and Zn in the plating layer of the invention examples and comparative examples were measured by inductively coupled plasma emission spectrometry (ICP-OES). That is, samples were taken from the unprocessed portion of the invention and comparative examples (V bending that is not point), was dissolved plating layer with aqueous 10% HCl, and analyzed. Energizing the plasma to each solution, to excite the constituent elements, by measuring the position and intensity of the emission line (spectral lines) emitted was identified and surveying of each element.
[0093]
　The configuration of the invention examples and comparative examples were confirmed by the aforementioned means shown in Table 3. Remainder of the average composition of the surface layer and the intermediate layer shown in Table 3 was Fe and impurities.
[0094]
[table 3]

[0095]
　Further, the fatigue characteristics of the invention examples and comparative examples were obtained by the above means (anti LME resistance), phosphate treatment resistance, coating adhesion, and the weldability was confirmed by the following method.
[0096]
　Fatigue Properties of Examples and Comparative Examples were evaluated by the following means. In the steel cross section in the thickness direction of the V bending processed portions of the examples and comparative examples, by observing the reflected electron image with a scanning electron microscope (SEM) and the reflected electron detector, liquid metal embrittlement cracks ( to observe the presence or absence of the occurrence of LME). Then, the sample is a sample and cracks cracks does not occur has occurred terminates in plating layer were evaluated as good (GOOD) Fatigue characteristics. On the other hand, the sample cracks extend to the base material over the plating layer was evaluated as defective (BAD) Fatigue characteristics.
[0097]
　Phosphating of Examples and Comparative Examples were evaluated by the following means. Each sample phosphate salt coating is formed which is phosphate treatment, lysed with ammonium bichromate solution, removed, and monitoring the difference in weight steel before and after removal of the coating, phosphate this It was considered adhesion amount of the coating. The deposition amount 2.0 g / m 2 of the above samples were evaluated good in phosphating properties (GOOD). On the other hand, the amount of adhesion 2.0 g / m 2 Sample of less than, was evaluated as bad for phosphating properties (BAD).
[0098]
　Paint adhesion of Examples and Comparative Examples were evaluated by the following means. Each sample was electrodeposition coating was immersed for 500 hours in aqueous 5% NaCl solution having a temperature of 50 ° C.. After immersion, the test area the entire surface of 60 mm × 120 mm, adhered to polyester tape, then pulled off. Measuring the area of a region where the coating film by tape peeling was peeled was determined coating exfoliation rate (%) based on the following equation.
　Coating peeling rate = (A2 / A1) × 100
　A1 is the area of the test area (60 mm × 120 mm = 7200Mm 2 are), A2 is the area of a region where the coating film is peeled off (mm 2 is). Samples of the coating film peeling rate is less than 5.0% was evaluated as good (GOOD) for paint adhesion. On the other hand, the coating film peeling rate of 5.0% or more of the samples was evaluated as defective (BAD) for paint adhesion.
[0099]
　Weldability of Examples and Comparative Examples were evaluated by the surface resistivity. Surface resistivity of the samples, using a pressurized DC inverter power supply at pressure 250 kgf, was calculated from the voltage value when a current flows 2A to the sample. Samples value of surface resistance is less than 20 m [Omega, was evaluated as good (GOOD) for weldability.
[0100]
　Fatigue characteristics of the invention examples and comparative examples were confirmed by the aforementioned means (anti LME resistance), shown phosphating resistance, coating adhesion, and weldability in Table 4.
[0101]
[Table 4]

[0102]
[Evaluation Results]
　As shown in Table 3, improvement in the alloy form and composition of the plating layer, as well, is performed improvement in the thickness of the oxide formed as the outermost surface layer of the plating layer, the invention examples of hot the stamping member, either, it can be seen that the fatigue characteristics improve the molded bodies based on suppression of LME generation, both the improvement of phosphating of moldings has been achieved.
[0103]
　In contrast, not subjected to improvement in the alloy form and composition of the plating layer, for hot stamping molded article of Comparative Example, both, the fatigue characteristics, phosphating properties, and one of the weldability, it can be seen that that has not been sufficiently improved.
[0104]
　Comparative Example 101, since it was produced using a plating bath Al content is insufficient, it is impossible to prevent the LME. Therefore, the fatigue characteristics of the comparative example 101 was poor.
　Comparative Example 102, since it was produced using a plating bath Zn content is insufficient, the organization of the intermediate layer becomes inappropriate due to Zn deficient. Therefore, phosphating of Comparative Example 102 is impaired, coating adhesion was poor.
　Comparative Example 103, since the alloying temperature in the hot stamp was too high, the film thickness of the oxide layer becomes excessive, weldability was poor.
　Comparative Example 104, since the alloying temperature in the hot stamp was too low, alloying of the plating layer becomes insufficient, Zn-rich phase occurs, it is impossible to prevent the LME. Therefore, the fatigue characteristics of the comparative example 104 was poor.
　Comparative Example 105, since the alloying time in the hot stamp is too long, the thickness of the oxide layer becomes excessive, weldability was poor.
　Comparative Example 106, since the alloying time in the hot stamp was too short, became insufficient heating for alloying. Therefore, in Comparative Examples 106 LME occurs, the fatigue characteristics deteriorated. In Comparative Example 106, the heating is less oxide amount because it is insufficient, the phosphate treatability and coating film adhesion is insufficient.
　Comparative Example 107, since the holding time in the alloying temperature and hot stamp was excessive, the film thickness of the oxide layer becomes excessive, weldability was poor.
Industrial Applicability
[0105]
　According to the present invention, the hot stamp molded plating layer is formed on the surface of the base material, both the fatigue properties and the phosphating property is sufficiently exhibited. Accordingly, the present invention is particularly promising in the field such as structural members for use in an automobile or the like.
DESCRIPTION OF SYMBOLS
[0106]
　1 hot stamping molded body
　10 base material
　20 plated layer
　21 the interfacial layer
　22 intermediate layer
　23 oxide layer
　30 Al-Zn-based plating layer
　40 Zn-based plating layer
　50 Al-based plating layer
　60 Kasei crystal
　70 transparent region

claims

Base material and
　the plated layer;
a hot stamping member comprising,
　said plating layer comprises, in order toward the surface side from the base material side includes an interfacial layer, an intermediate layer, an oxide layer, a ,
　the interface layer, tissue total 99 area% or more of the alpha iron, Fe 3 Al, and include FeAl, average Al content is in the range of the 8.0 mass% or more 32.5 mass% or less, limited average Zn content is below Zn content super 5 wt% of the base material, the remainder of the chemical component comprises Fe and impurities, and the average thickness is at 1.0μm or more,
　the intermediate layer, the tissue There total 99 area% or more Fe (Al, Zn) 2 and Fe 2 (Al, Zn) 5 wherein the average is a Al content of 30 to 50 mass%, average Zn content of 10 to 40 mass% There, the chemical components remainder includes Fe and impurities, and the average film The thickness is not less than 5.0 .mu.m,
　the oxide layer has an average thickness is 0.1 ~ 3.0 [mu] m
hot stamping molded article, characterized in that.
[Requested item 2]
　The interfacial layer has an average thickness is 1.0 ~ 10.0 [mu] m
hot stamping molded article according to claim 1, characterized in that.
[Requested item 3]
　The total weight per unit area of Al and Zn of the plating layer is 20 g / m 2 or more 100 g / m 2 or less
hot stamping molded article according to claim 1 or 2, characterized in that.
[Requested item 4]
　The plating layer may further include a zero mean mass percent and 10.0 mass% or less of Si,
　in the intermediate layer, the Fe (Al, Zn) 2 and the Fe 2 (Al, Zn) 5 0 ~ 50 of area percent, Fe (Al, Si) are replaced by
a hot stamping molded article according to any one of claims 1 3, characterized in that.