Technical field
[0001]The present invention, hot press at the workability (lubricity) and corrosion resistance (corrosion resistance after painting) can be well expressed, of the preferred Al-based plated steel sheet as a hot press.
BACKGROUND
[0002]Recently, for environmental protection and suppression of global warming, there is an increasing inhibit request the consumption of fossil fuels, the demand has affected to various manufacturing industries. No exception for the automotive industry to produce a moving means indispensable to everyday life such as to suppress the consumption of fuel, such as by reducing vehicle weight are demanded. Many automotive components are iron, which is formed in particular steel, to reduce the total weight of the steel sheet used, weight of the vehicle body, is important for eventual fuel consumption suppression.
[0003]However, since the motor vehicle is required to secure safety, simply it is not allowed to reduce the plate thickness of the steel sheet is required to have the maintenance of the mechanical strength of the steel sheet. Demand for such steel sheet, not only in the automotive industry, has increased as well in a variety of manufacturing industries. Therefore, by increasing the mechanical strength of the steel sheet, even thinner than the steel plate which has been conventionally used, for the steel sheet which can maintain or improve the mechanical strength, research and development have been conducted.
[0004]In general, a material having excellent mechanical strength, in a molding process of bending, etc., tend to formability, shape fixability is lowered, the case of processing into complex shapes, processing itself becomes difficult. As a means for solving the problems of the moldability, so-called "hot press method (hot stamping method, a hot press method, die quenching method, also called press hardening.)" Can be mentioned. In the hot pressing method, by heating to a material that is molded object once high temperature (austenite region), after shaping by performing press working with respect to the softened steel sheet by heating and cooling.
[0005]According to this hot pressing process, since the once softened by heating to a high temperature material, the material can be easily press working, further, by hardening effect due to cooling after molding, the mechanical strength of the material it is possible to increase. Thus, this hot pressing, it is possible to obtain a good shape fixability and high mechanical strength and both the molded article.
[0006]
　However, if the steel sheet to hot-pressing, for example, when heated to a high temperature of at least 800 ° C., the iron is oxidized scale (oxide) on the surface is generated. Therefore, after the hot pressing, the step of removing the scale (descaling process) is required, the productivity is lowered. Furthermore, in the case of a molded article corrosion resistance is required, subjected to rust-preventive treatment to the surface of the molded article after the hot pressing, or for forming a metal film, surface cleaning process or surface treatment step is required, even more productivity is reduced.
[0007]
　Examples of suppressing such a decrease in productivity, and a method of forming a film on the steel sheet. Generally, the coating on the steel sheet, various materials such as organic materials and inorganic materials are used. Of these zinc-plated steel sheet with a sacrificial corrosion protection action on the steel sheet, in view of the corrosion protection and the steel sheet production technology, widely used in the automotive steel sheets, etc. (Patent Document 1).
[0008]
　However, the heating temperature in the hot press (700 ° C. or higher, 1000 ° C. or less) is higher than such boiling point of the decomposition temperature and Zn (zinc) in the organic material. Therefore, when heating the steel sheet for hot press, since the plated layer of the steel sheet surface or evaporate or oxidize, the surface properties are significantly deteriorated, slidability also be exacerbated during hot pressing . To prevent this by containing aluminum in a predetermined range in the zinc plating layer, further measures such as forming a coating that melts at a press temperature is needed on the galvanized layer (Patent Document 2).
[0009]
　Therefore, with respect to the steel sheet is heated to a high temperature during hot pressing, for example, as compared with the metal coating of the organic material film or Zn-based form a high boiling point Al (aluminum) -based metal film, the so-called Al-based plated it is desirable that the steel plate. By forming the Al-based metal coating, it is possible to prevent the adhesion of scale to the steel sheet surface, thereby improving the productivity because the process is not necessary, such as descaling process. Further, since the metal film of Al-based also anticorrosive effect is also improved corrosion resistance after painting.
[0010]
　Such a method of using an Al-based plated steel sheet formed on the steel for hot pressing having a predetermined steel composition of metal coating Al systems have been proposed (e.g., see Patent Document 3). One of the challenges of hot pressing an aluminum-based plating material as disclosed in Patent Document 3, there is improvement in the workability during hot pressing. The workability during hot pressing, Dari wedged mold for Fe-Al-Si plating layer formed during the heating is rigid, or deposited in a mold for the friction coefficient is large, such as there is a concern. These concerns, scratched surface of the product, which may lower the appearance quality.
[0011]
　As a means for solving the above problems, a method of adhering a coating layer containing zinc oxide (ZnO) on the plating surface has been proposed (e.g., see Patent Document 4). The method disclosed in Patent Document 4, specifically, for the shedding inhibition of ZnO a resin component and a silane coupling agent or the like is deposited on the surface of the steel sheet a coating layer containing as a binder, 300 ° C. or higher during hot pressing, 500 ° C. to volatilize the organic solvent component of the binder in the following is a way to leave only ZnO. Such method, an organic solvent is burned, and the ZnO and gold metal by voids generated by evaporation becomes point contact, lubricity is to be improved.
[0012]
　In addition to lubricity during hot pressing, in performing the heating by the heating and infrared in the heating furnace, and Atsushi Nobori characteristics, chemical conversion treatability after hot pressing, to improve the corrosion resistance after painting a method utilizing an oxide of ZnO or the like has been proposed (e.g., see Patent documents 5 to 8).
CITATION
Patent Document
[0013]
Patent Document 1: JP 2010-242188 Patent Publication
Patent Document 2: JP 2011-32498 JP
Patent Document 3: JP 2000-38640 JP
Patent Document 4: WO 2009/131233 Patent
Patent Document 5: JP 2012-92365 JP
Patent Document 6: JP 2013-227620 Patent Publication
Patent Document 7: JP 2013-221202 JP
Patent Document 8: WO 2014/181653
Summary of the Invention
Problems that the Invention is to Solve
[0014]
　As disclosed in Patent Documents 4 to 8, by forming a surface coating layer containing ZnO on the Al-based plating, slidability during hot pressing is improved. However, the present inventors have studied, preheat the Al-based plated steel sheet before hot pressing and heated placed on a conveyor for conveying, for ZnO film superposition portion in contact with the conveyor is lost, the reduces the hot slidability of the site, it was found that it is not possible as a whole obtain sufficient workability (lubricity).
[0015]
　The present invention was made in view of the above circumstances, to suppress disappearance of ZnO at the contact portion between the conveyor during heating, hot pressing time of workability (lubricity) and corrosion resistance (corrosion resistance after painting) and to provide a suitable Al-based plated steel sheet as well is capable of expressing, for hot pressing and the like.
Means for Solving the Problems
[0016]
　In order to solve the above problems, the present inventors first investigated the reason why ZnO film superposition portion in contact with the conveyor is lost. Usually, the atmospheric furnace in the continuous heating Al present in the organic resin component and the plated surface is oxidized by combining with atmospheric oxygen. However, becomes poor supply of oxygen in the overlapping portion of the plated steel sheet and the conveyor is in contact, Al is oxidized by reduction of ZnO. That is, pairs reaction of the oxidation of Al present in the organic resin component and the plated surface, ZnO is reduced to metallic Zn, more it was found to disappear with the metal Zn vaporizes.
[0017]
　Under such circumstances, the present inventors have further the Al-based plating layer surface formed on the surface of the steel sheet, and the ZnO particles, and an organic resin used as the binder, oxidizing agent for suppressing Al loss ZnO ( oxygen and supplies) to al, by forming the surface film containing the disappearance of ZnO is suppressed at the contact portion with the conveyor during the heating, thus during hot press workability and a sufficiently express corrosion resistance thereby to obtain a knowledge that.
[0018]
　Based on the above findings, the present inventors have completed the invention. Its gist is as follows.
[0019]
　[1] and the base material,
　wherein the Al-based plating layer formed on at least one surface of the base material,
　a surface coating layer formed on the Al-based plating layer, and the ZnO particles, and an organic resin, said surface 10 mass% or more with respect to the coating layer total weight, and acetylacetonate of 30 wt% or less, as well as containing an average particle size of the ZnO particles, 0.10 .mu.m or more and less 5.00, the ZnO amount of adhering particles of metal Zn converted at 0.5 g / m 2 or more, 10.0 g / m 2 or less, and the surface coating layer,
　characterized in that it comprises the, Al-based plated steel sheet for hot press.
[2] Al-based plated steel sheet of the present invention, characterized in that on both surfaces of the base material, the Al-based plating layer and the surface coating layer was formed.
[0020]
　The Al-based plated steel sheet according to the present invention is performed to the components of the surface coating layer formed as the outermost layer, the adhesion amount of ZnO grains, which is one of the element, the improvement for. As a result, according to the Al-based plated steel sheet according to the present invention, the hot press when the workability (lubricity) and corrosion resistance (corrosion resistance after painting) can be sufficiently exhibited.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
[1] conceptual cross-sectional view of the Al-based plated steel sheet of the present invention provided with the Al-based plating layer and the surface coating layer on one side.
[2] a cross-sectional conceptual view of Al-based plated steel sheet of the present invention on both surfaces, providing the Al-based plating layer and the surface coating layer.
DESCRIPTION OF THE INVENTION
[0022]
　Hereinafter, suitable as a hot press, Al-based plated steel sheet according to the present invention (hereinafter, simply referred to as "steel plate") describing the embodiments in detail. The following embodiments are not intended to limit the present invention. The constituent elements of the above embodiments, those skilled person that can be easily replaced, or substantially the same. Moreover, various forms included in the embodiment, a person skilled in the art can arbitrarily combined within obvious limits.
[0023]
　It shows an example of Al-based plated steel sheet of the present invention in FIG. Al-based plated steel sheet 100 of the present invention, by the Al-based plating layer 103 is formed on the surface of the base 101, to form a surface film layer 107 on the surface of the Al-based plating layer 103 configured. The surface coating layer 107 may include acetylacetonate, made of ZnO particles 109 conjugated with the organic resin 111. Al-based plating layer 103, the surface coating layer 107, may each be formed on both surfaces of the base material 101 (see FIG. 2). Each layer will be described in detail below.
[0024]
　
[preform 101]
　The Al-based embodiment coated steel sheet 100, (member for forming the Al-based plating layer 103) base material 101 used for, hot press after plating layer formed be performed, excellent mechanical strength (tensile strength, yield point, elongation, diaphragm, hardness, impact value, fatigue strength, which means the properties related to mechanical deformation and fracture of the creep strength, etc.) using the member as having. For example, using a member having enhanced hardenability by the addition of C (carbon) and alloying elements. Thus, as will be described later, with respect to Al-based plated steel sheet 100 obtained by forming an Al-based plated layer 103 and the surface film layer 107, in the automotive parts obtained by applying the hot press, superior mechanical strength is expressed.
[0025]
　That is, the base material 101 of the Al-based plating steel sheet 100 of the present embodiment can be used known ones as long as it has excellent mechanical strength. For example, although those having the following ingredients can be used as the base material 101, components of the base material 101 is not limited to this.
[0026]
　Preform 101 of the present embodiment, for example, by mass%, C: 0.01% or more, 0.5% or less, Si: 2.0% or less, Mn: 0.01% or more, 3.5% or less , P: 0.1% or less, S: 0.05% or less, Al: 0.001% or more, 0.1% or less, N: contains 0.01% or less, Ti: 0.005% or more, 0.1% or less, B: 0.0003% or more, 0.01% or less, Cr: 0.01% or more, 1.0% or less, Ni: 0.01% or more, 5.0% or less, Mo: 0.005% or more, 2.0% or less, Cu: 0.005% or more, can contain one or more than 1.0% optionally, further W, V, Nb, can contain elements such as Sb, the balance consists of Fe and unavoidable impurities. Hereinafter, each component added in the base material 101 will be described in detail. Units% of each component means all mass% in the following description.
[0027]
　(C: 0.01% or more, 0.5% or less)
　carbon (C) is inevitably contained in steel, also be contained in order to ensure the mechanical strength for the purpose of the base material 101. Thereby excessively reducing the content of C is to increase the smelting cost, it is preferable to contain 0.01% or more. Further, when the content of C is 0.1% or more, because a large amount is not necessary to add other alloying elements to improve the mechanical strength, a large effect of improving strength by the addition of C . On the other hand, when the content of C is 0.5 percent, but it is possible to further cure the preform 101, is easily melt cracking occurs. Therefore, C is 0.01% or more, preferably contained at 0.5% or less, from the viewpoint of melt-break preventing a strength increase of 0.1% or more, it added in a content of 0.4% or less it is more preferable to be. The content of C is 0.15% or more, still more preferably 0.35% or less.
[0028]
　(Si: 2.0% or less)
　of silicon (Si), such as is added as a deoxidizing agent, is an element inevitably contained in refining process of steel. However, since impairing the like surface properties as ductility lowered and the resulting hot-rolled process during excessive addition steel sheet production of Si, it is preferable that 2.0% or less.
　Further, Si is one of the strengthening element to improve the mechanical strength of the base material 101, similarly and C, and may be added in order to ensure the mechanical strength of interest. When the content of Si is less than 0.01%, hardly exhibits the strength improving effect, sufficient improvement in mechanical strength is difficult to obtain. Meanwhile, Si because it is also a oxidizable elements, the content of Si is 0.6 percent, when performing molten Al-based plating, decreased wettability, there is a possibility that the non-coating occurs . Therefore, Si is 0.01% or more, and more preferably added at a content of 0.6% or less. The content of Si is 0.05% or more, more preferably 0.5% or less.
[0029]
　(Mn: 0.01% or more, 3.5% or less)
　manganese (Mn), such as is added as a deoxidizing agent, is an element inevitably contained in refining process of steel. However, excessive addition of Mn impairs the quality of uniformity due to segregation of Mn during casting, the steel sheet is excessively hardened, hot, because it causes a decrease in ductility during cold working, 3.5% or less it is preferable that the. On the other hand, decreasing the content of Mn less than 0.01%, the process and cost increases, the content of Mn is preferably 0.01% or more. Therefore, Mn is preferably 0.01% or more, 3.5% or less.
　In addition, Mn is one of the strengthening elements of the base material 101, is also one of the elements to improve the hardenability. Further, Mn is also is effective suppressing the hot embrittlement due, which is one of the inevitable impurities S (sulfur). Therefore, the content of Mn by 0.5% or more, can be obtained improving hardenability and the effect of hot shortness suppressed. On the other hand, when the content of Mn is 3 percent, there is a possibility that the residual γ phase becomes too much strength decreases. Therefore, Mn is 0.5% or more, and more preferably added in an amount of 3% or less. The content of Mn is 1% or more, still more preferably 2% or less.
[0030]
　(P: 0.1% or less)
　phosphorus (P) is also a solid solution strengthening element while an element which is inevitably contained, which is an element which relatively inexpensively increase the strength of the base material 101. However, it is preferable to 0.001% the lower limit of the content of economic refining limits. On the other hand, when the content of P is 0.1 percent, there is a possibility that the toughness of the base material 101 is lowered. Therefore, the P content is 0.001% or more and 0.1% or less. The content of P is 0.01% or more, still more preferably 0.08% or less.
[0031]
　(S: 0.05% or less)
　sulfur (S) is an element inevitably contained, become starting points of fracture becomes inclusions in the matrix 101 as MnS, to inhibit ductility and toughness machining It becomes a factor of sexual degradation. Therefore, the S content is preferably as low, it is preferable to 0.05% the upper limit of the content. Meanwhile, since the increase in manufacturing costs in order to reduce the content of S is expected, the lower limit of the content is preferably set to 0.001%. The content of S is 0.01% or more, still more preferably 0.02% or less.
[0032]
　(Al: 0.001% or more, 0.1% or less)
　aluminum (Al) is a component contained in the base material 101 as a deoxidizer, but also plating inhibition element. Therefore, the upper limit of the content of Al is preferably 0.1%. On the other hand, although not the lower limit of the content of Al is particularly specified, from an economic refining limits, for example, preferably set to 0.001%. The content of Al is 0.01% or more, still more preferably 0.08% or less.
[0033]
　(N: 0.01% or less)
　nitrogen (N) is an element which is inevitably contained, from the viewpoint of stabilizing the various properties of the base material 101, it is preferable to fix the content Specifically, it is possible to fix on the basis of Ti, the content of elements such as Al. On the other hand, when the content of N is too large, Ti, becomes large content of such Al, an increase in the manufacturing cost of the base material 101 is expected, the upper limit of the content of N is set to 0.01% preferable.
[0034]
　(Ti: 0.005% or more, 0.1% or less, B: 0.0003% or more, 0.01% or less, Cr: 0.01% or more, 1.0% or less, Ni: 0.01% or more , 5.0% or less, Mo: 0.005% or more, 2.0% or less, Cu: 0.005% or more, one or more of 1.0% or
　less) (Ti: 0.005% or more 0.1% or less)
　of titanium (Ti) is one of the strengthening elements of the base material 101, is also an element improving the heat resistance of the Al-based plating layer 103 formed on the base material 101 surface. When the content of Ti is less than 0.005%, it is impossible to obtain the strength improving effect and heat resistance and sufficient. Meanwhile, Ti is excessively added, for example, by forming a carbide or nitride, the base material 101 is likely to be softened. In particular, when the content of Ti is 0.1 percent, is likely not to obtain the mechanical strength of interest. Therefore, Ti is 0.005% or more, it is preferably added at a content of 0.1% or less. The content of Ti is 0.03% or more, still more preferably 0.08% or less.
[0035]
　(B: 0.0003% or more, 0.01% or less)
　of boron (B) is an element which acts during quenching has the effect of improving the strength of the base material 101.
　When the content of B is less than 0.0003%, such effect of improving the strength is not sufficiently obtained. On the other hand, when the content of B is 0.01 percent, inclusions in the matrix 101 (e.g., BN, carbonitrides borides, etc.) is embrittled is formed, which may lower the fatigue strength. Therefore, B is 0.0003% or more, it is preferably added in a content of 0.01% or less. The content of B is 0.001% or more, still more preferably 0.008% or less.
[0036]
　(Cr: 0.01% or more, 1.0% or less)
　Chromium (Cr), the Al-based plating layer 103 when forming the Al-Fe alloy layer alloyed base material an Al-based plated layer 103 101 by generating the interface between, Al-based plating layer 103 has an effect of suppressing generation of AlN which causes peeling off. Further, Cr is one of the elements to improve the wear resistance, is also one of the elements to improve the hardenability. When the content of Cr is less than 0.01%, it is impossible to sufficiently obtain the aforementioned effect. On the other hand, when the content of Cr is 1.0 percent, also increases the manufacturing cost of the steel sheet not only the above effect is saturated. Therefore, Cr is 0.01% or more, it is preferably added at a content of 1.0% or less. The content of Cr is 0.5% or more, more preferably 1.0% or less.
[0037]
　(Ni: 0.01% or more, 5.0% or less)
　of nickel (Ni) has the effect of improving the hardenability during hot pressing. Further, the Ni also has the effect of increasing the corrosion resistance of the base material 101. However, when the content of Ni is less than 0.01%, it is impossible to sufficiently obtain the aforementioned effect. On the other hand, when the content of Ni is 5.0 percent, also increases the manufacturing cost of the steel sheet not only the above effect is saturated. Therefore, Ni is 0.01% or more, it is preferably added in a content of 5.0% or less.
[0038]
　(Mo: 0.005% or more, 2.0% or less)
　of molybdenum (Mo) has the effect of improving the hardenability during hot pressing. Further, the Mo has the effect of increasing the corrosion resistance of the base material 101. However, when the content of Mo is less than 0.005%, it is impossible to sufficiently obtain the aforementioned effect. On the other hand, if the content of Mo is 2.0 percent, also increases the manufacturing cost of the steel sheet not only the above effect is saturated. Therefore, Mo is preferably added in an amount of 2.0% 0.005% or more.
[0039]
　(Cu: 0.005% or more, 1.0% or less)
　of copper (Cu) has the effect of improving the hardenability during hot pressing. Further, the Cu also has the effect of increasing the corrosion resistance of the base material 101. When the content of Cu is less than 0.005%, it is impossible to sufficiently obtain the aforementioned effect. On the other hand, when the content of Cu is 1.0 percent, also increases the manufacturing cost of the steel sheet not only the above effect is saturated. Therefore, Cu is 0.005% or more, it is preferably added at a content of 1.0% or less.
[0040]
　(W, V, Nb, Sb )
　Incidentally, the base material 101 of the present embodiment, in addition to the plurality of elements of the tungsten (W), vanadium (V), niobium (Nb), antimony (Sb) etc. elements may be selectively added. The addition amount of these elements, if known range may be employed for any of the added amount.
[0041]
　(Balance)
　the remainder of the base material 101 is iron (Fe) and only unavoidable impurities. The inevitable impurities, a component to be mixed in the course of the components, or the production is contained in the raw material, refers to intentionally not were contained Ingredient in the base material 101.
[0042]
　Such preform 101 formed by component, by hardening by heating due to hot pressing, it is possible to have a mechanical strength of at least about 1500 MPa. There is a steel sheet having such excellent mechanical strength but, if processed by hot pressing, it is possible to perform the press in a state softened by heating, can be easily molded. Further, after pressing, the base material 101 which is cooled from the high temperature, high mechanical strength can realize, may also be maintained or improved mechanical strength as the thin to the thus lighter.
[0043]
　[Al-based plating layer
　103] Al-based plating layer 103 is formed on at least one surface of the base material 101. Al-based plating layer 103 is, for example, can be formed by hot dipping method, not the forming method is not limited to this. Al-based plating layer 103 only needs to contain Al as a main component. Herein, the term "main component" refers to containing Al 50 mass% or more. Preferred major amount is, Al is not less than 70 mass%, Al-based plating layer 103 preferably contains an Al 70 mass% or more. Components other than Al is not particularly limited, may include Si at any concentration.
[0044]
　Al-based plating layer 103 prevents corrosion of the base material 101. Also, Al-based plating layer 103, when the hot press prior to the heating to prevent the scale (iron oxide) is formed on the surface of the steel sheet. Therefore, by Al-based plating layer 103 on at least one surface of the base material 101 is present, the scale removal step can be omitted and surface cleaning step and surface treatment step, and thus improve the productivity of automobile parts it can be. Furthermore, Al-based plating layer 103, and coating by an organic material, other metal-based material (e.g., Zn-based materials) because of its high melting point than the coating by, during hot pressing, and can be processed at high temperatures Become.
[0045]
　A part or all of Al included in the Al-based plating layer 103, and when hot-dip plating, during hot pressing, may be Fe alloyed with the base material 101. Therefore, Al-based plating layer 103 is not necessarily limited to component is formed of a single layer is constant, partially alloyed layer (alloy layer), or changes from a concentration gradient surface steel - it may become encompasses aluminum gradient alloy layer.
[0046]
　[Surface film layer 107 '
　surface film layer 107 is formed on the Al-based plating layer 103. Surface film layer 107 has an average particle diameter of 0.10μm or more, and less ZnO particles 109 5.00, while containing an organic resin 111, 0.5 g / m deposition amount of metal Zn terms of the ZnO particles 109 2 above, 10.0 g / m 2 is required to be less. In the case where the Al-based plated layer 103 on both surfaces of the base material 101 is formed, it can form a surface film layer 107 on at least one side of the Al-based plating layer 103.
[0047]
　Surface film layer 107, for example, can be formed using a solution prepared by mixing the components in the various solvents mentioned above such as water or an organic solvent.
[0048]
　(ZnO particles 109)
　in order to obtain good workability and corrosion resistance in hot pressing, on the Al-based plating layer 103, an average particle diameter of 0.10μm or more, the following ZnO particles 109 5.00 is a metal Zn terms 0.5 g / m 2 or more, 10.0 g / m 2 is required to be formed at a coverage of less. ZnO particles 109 contacts the mold and the point to improve the workability by lowering the dynamic friction coefficient. However, the average particle size is less than 0.10μm of ZnO particles 109, since the contact point between the ZnO grains 109 and the mold is too large at the time of press working, can not be sufficiently improved processability.
[0049]
　On the other hand, the average particle size of the ZnO particles 109 is more than 5.00, weldability is deteriorated. ZnO is an insulating, when the particle size is small, it is possible to sufficiently ensure the current point to collapse during welding 圧加. However, ZnO particles 109 is less likely to collapse during the welding 圧加 average particle diameter of the ZnO grains 109 grow to larger than 5 [mu] m. As a result, it is impossible to ensure a sufficient current supply point, weldability since dust is likely out worse.
[0050]
　The method of measuring the average particle size of the ZnO particles 109 is not particularly limited. For example, scanning electron microscopy (SEM, Scanning Electron Microscope) such as by, by observing any 10 or more ZnO particles 109 at 2000 times to measure the maximum particle diameter of each particle, be determined by calculating the average value good. Alternatively, using a particle size distribution measuring device may determine the average particle size of the ZnO particles 109.
[0051]
　Further, 0.5 g / m at a coverage of all of the ZnO particles 109 of the surface coating layer 107 is metal Zn terms 2 by weight, it is impossible to obtain sufficient workability during hot pressing. Further, as the amount of deposition of the ZnO particles 109 increases, although the workability and the corrosion resistance of the steel sheet is increased, since the film resistance of the surface coating layer 107 is increased, the steel sheet resistance weldability (for example, spot weldability) There is reduced. In other words, the adhesion amount of all of the ZnO particles 109 of the surface coating layer 107 is 10.0 g / m of a metal Zn terms 2 exceeds, it is difficult to obtain a sufficient resistance weldability of the steel sheet.
[0052]
　Incidentally, adhesion of ZnO particles 109 to Al-based plating layer 103 above can be measured by a calibration curve method using a XRF (fluorescent X-ray, X-ray Fluorescence).
　Herein, the term coating weight and, at the time of hot press, a deposition amount before heating placed on a conveyor.
[0053]
　(Organic resin 111)
　in the steel sheet of the present embodiment, the organic resin 111 which is a component of the surface coating layer 107, as long as it functions as a binder to hold the ZnO particles 109 in the film is not particularly limited. The organic resin 111 is lost by burning during hot pressing prior to the heating, it does not affect the press working, welding, or the like is a subsequent process. The organic resin 111 when the drug water-based, it is preferable to use a ZnO as well as stable cation resin in weakly alkaline, for example, can be used cationic urethane resin and a cationic acrylic resin. In the present embodiment, for the concentration (g / kg) ratio of the organic resin in the drug, not specified. The resin that can be used as the organic resin 111 of the present invention, cationic urethane resin (Dai-ichi Kogyo Seiyaku Co., product name SUPERFLEX 650), and the like.
[0054]
　In order to sufficiently express the function as a binder in the organic resin 111, the content of the organic resin 111 on the entire surface coating layer 107, by mass%, 10% or more, it is preferable that 60% or less. When the content is less than 10%, acts as a binder is not sufficiently expressed, the coating film before the heating is likely to peel. In order to get a stable an action as the binder, the content of the organic resin 111, more preferably 15% or more. On the other hand, when the content of the organic resin 111 is 60 percent, the occurrence of unpleasant odor upon heating becomes remarkable.
[0055]
　(Acetylacetonate)
　in steel sheet of the present embodiment, acetylacetonate included surface film layer 107, the Al inter alia a surface coating layer 107 as an oxidizing agent for oxidation is extremely important. In the contact portion between the Al-based plated steel sheet 100 and the conveyor during continuous heating, the Al of the organic resin 111 Yamekki surface is oxidized, due to this, ZnO is reduced to metallic Zn, thus metallic Zn is vaporized. However, by the surface coating layer 107 to include a higher ZnO reducing property (hard to be oxidized) acetylacetonate, the behavior of ZnO is suppressed, it is possible to suppress the result loss of ZnO. That is, by the addition of acetyl acetonate to the surface coating layer 107, loss contributes ZnO lubricity is suppressed, the workability and corrosion resistance in hot pressing can be stably obtained.
[0056]
　Acetylacetonate may be added per se, or may be added in the form of acetylacetonate complex (acetylacetonate metal salt). The acetylacetonato complex, copper complex, a manganese complex, a nickel complex, zinc complex, titanium complex, vanadyl complexes and the like. Since acetylacetonate zinc among them (zinc complex) acts as a ZnO source to produce ZnO in itself, a more preferred.
[0057]
　Further, ZnO, the total surface film layer 107 medium, including acetyl acetonate, amount of acetylacetonate is less than 10% by mass acetylacetonate terms sufficiently suppress reduction of ZnO, disappearance it can not be. As a result, hot lubricity is deteriorated. Furthermore, in order to reduce the content of zinc oxide acetylacetonate is small, also decreases corrosion resistance after coating. On the other hand, when it exceeds 30 wt%, acetylacetonate becomes poor paint adhesion since solubility, corrosion resistance after coating is deteriorated.
[0058]
　Incidentally, acetylacetonate equivalent amount is determined as follows. First, the peeling at fuming nitric surface coating layer 107 of a given area, to calculate a film adhesion amount by measuring the weight before and after peeling. Then, the post-peeling coating was sufficiently stirred in a known amount aqueous solution of 30 ° C. to elute acetylacetonate in the film by, with the acetylacetonate concentration of the solution was measured by a calibration curve method of liquid chromatography, an aqueous solution than acetylacetonate weight and film coating weight in the film than the amount calculated acetylacetonate ratio.
[0059]
　Next, the method of forming the surface film layer 107 on the Al-based plating layer 103 above is not particularly limited, but the main component of the, ZnO particles 109, Ya aqueous solution prepared by dissolving the organic resin 111 and acetylacetonate solvent, on the Al-based plating layer 103 was applied by a known method such as a roll coater or a spray can be formed by drying. Although there is no particular limitation on the drying method after coating, hot air, the IH (induction heating), NIR (near infrared), such as electric heating, can be used each method. Furthermore, the heating temperature in drying, taking into account the glass transition temperature of the organic resin 111 is a binder (Tg), is preferably set as appropriate.
[0060]
　As described above, according to the Al-based plated steel sheet 100 of the present embodiment, the surface coating layer 107 of the outermost layer, excellent lubricity at the hot pressing without ZnO film is lost at the contact portion between the conveyor to express, it is possible to achieve excellent corrosion resistance after excellent workability and hot pressing during hot pressing or the like. Further, according to the Al-based plated steel sheet 100 of the present embodiment, the presence of surface film layer 107 having excellent lubricating properties, it is possible to suppress the adhesion to the mold. Even if the Al-based plating layer 103 was powdering by heating, the presence of the surface coating layer 107 having excellent lubricity, the molds used in the subsequent press powder (Al-Fe powder, etc.) that adhesion is suppressed. Therefore, in the case of hot pressing the Al-based plated steel sheet 100 of the present embodiment, such step of removing the Al-Fe powder and adhesion to the mold is not required, it is possible to achieve excellent productivity .
Example
[0061]
　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.
[0062]
　Cold-rolled steel sheet having a composition shown in Table 1 (the balance Fe and unavoidable impurities, thickness 1.4 mm) was used to form an Al-based plated layer 103 in Sendzimir method on both surfaces of the cold-rolled steel sheet. Al-based annealing temperature of the plating layer 103 formed was about 800 ° C.. Al-based plating bath, using a conventional Al-based plating bath.
　Incidentally, the amount of Al-based plating layer 103 adhering to the base material 101, in the gas wiping method, one side 160 g / m 2 was adjusted to.
[0063]
[Table 1]

[0064]
　Thereafter, the dispersant of ZnO particles 109 (manufactured by Sakai Chemical Industry Co., Ltd., product name DIF-3ST4S) and as the organic resin 111, a cationic urethane resin (Dai-ichi Kogyo Seiyaku Co., product name SUPERFLEX 650) to and acetylacetonate the mixture was adjusted solution was applied on the Al-based plating layer 103 by a roll coater, dried at peak metal temperature of 80 ° C., to form a surface coating layer 107. As for Sample No. 17, without using an organic resin 111, and dried at 80 ° C. After applying the cyclopentasiloxane containing dispersed ZnO particles 109.
　There was thus obtained the Al-based plated steel sheet of each test example. The above solution for forming a surface coating layer 107 shown in Table 2, was adjusted by using commercially available reagents, is mixed with distilled water
it was. Here, the "Zn adhered amount" in Table 2, 1 values obtained the total coating weight in terms of the mass of metal Zn in ZnO particles 109 per square meter (unit is "g / m 2 ") be It was determined by a calibration curve method using a XRF.
[Measurement conditions]
　The amount of acetylacetonate, the particle size of the ZnO particles 109, ZnO coating weight were identified in the following manner.
1. The addition amount of the acetylacetonate
　, as described above, a surface coating layer 107 was peeled off with fuming nitric acid, and the peeled acetylacetonate concentration was determined by the calibration curve method of liquid chromatography.
2. The particle size of the ZnO particles 109
　Manufactured by JEOL Ltd. scanning electron microscope (product name: JSM-7800F) with the ZnO particles 109 was observed at 2000-fold magnification, measuring the maximum particle size of 20 ZnO particles 109, calculates an average value and the particle size of the ZnO particles 109.
3. ZnO deposition amount
　manufactured by Rigaku Corporation X-ray fluorescence analyzer (product name: ZSX Primus) was measured using a ZnO deposition amount under the following conditions. For the measurement, in advance, preparing a calibration curve showing the relationship between fluorescent X-ray intensity of metal Zn amount conversion, based on the calibration curve to determine the deposition amount.
　Measurement diameter: 30mm
　Measurement Atmosphere: Vacuum
　Spectrum: Zn-K [alpha
　with peak number counting Zn-K [alpha X-ray fluorescence analysis was measured under the above conditions.
[0065]
[Table 2]

[0066]
　Next, the way various properties of the steel sheet of each test example was prepared like was evaluated by the following method. The results are shown in Table 3.
[0067]
　(1) Hot lubricity (lubricating property)
　against steel of each test example, by performing the mold pull-out tests in hot, to evaluate hot lubricity. More specifically, by inserting the steel sheet of each test example of 30 mm × 350 mm into the furnace, sandwiched between 2 sheets of width 60 mm × length 200 mm × thickness 30 mm SiC plate made of, and heated for 6 minutes at 900 ° C., the furnace after removal, the pressing SKD11 steel Tairakin type (width 50 mm × length 40 mm) from both sides of the steel sheet at about 700 ° C., was drawn. By sandwiching the both sides of the steel sheet by the SiC plate, the supply of oxygen from the surface sufficiently prevented, they simulate a situation in which ZnO film superposition portion in contact with the conveyor disappears at more severe conditions. Pressing and measuring the load and pulling loads, the value obtained in / pull-out load (2 × pressing load) was hot friction coefficient. The value of the dynamic friction coefficient means that the better hot lubricity is small, in the evaluation shown in Table 3, was passed less than 0.52.
[0068]
　(2) corrosion resistance after painting
　by inserting steel sheet of each test example of 120 mm × 200 mm into the furnace, placed in a direction contacting the evaluation surface on the SiC furnace pedestal, 50 mm × 50 mm × heated to 900 ° C. while carrying the SUS304 block of 70 mm, heated standing furnace 6 minutes at 900 ° C., after removal from the oven and immediately quenched sandwich in a stainless steel mold. The cooling rate at this time was about 0.99 ° C. / sec. Then sheared to 70 mm × 150 mm from the center of each steel sheet after cooling, Nippon Parkerizing Co., Ltd. chemical treatment solution after (PB-SX35) in the chemical conversion treatment, Nippon Paint Co., Ltd. electrodeposition coating ( the POWERNICS 110) thickness was applied to a 20 [mu] m, baked at 170 ° C.. Incidentally, inserting each steel sheet 70 mm × 150 mm with a welded thermocouple in the atmosphere furnace set at 900 ° C., where a temperature of until 900 ° C. was measured to calculate the average heating rate, 5 ° C. / sec Met.
[0069]
　Corrosion resistance after painting evaluation was carried out by the method specified in the Society of Automotive Engineers enactment of JASO M609. That is, crosscut in advance cutter in the coating film, the width of blistering the coating from the cross-cut after the corrosion test 180 cycles (60 days) the (one-sided maximum value) was measured. The value of the width of blistering the coating means the superiority of the smaller corrosion resistance, in the evaluation shown in Table 3, was evaluated as acceptable 5mm or less.
[0070]
　(3) Spot weldability
　spot weldability was evaluated as follows.
　Put steel of each test example was produced in the heating furnace, and heated standing furnace 6 minutes at 900 ° C., and quenched by sandwiching immediately mold stainless after removal. The cooling rate at this time was about 0.99 ° C. / sec. Then, sheared each steel sheet after cooling to 30 × 50 mm, the optimal spot welding current range - were measured (upper current limit current). Measurement conditions are as shown below. The lower limit current is a current value when a nugget diameter 3 × (t) 0.5, the upper limit current was scattered generated current.
　Current: DC
　electrode: chromium copper, DR (tip 6mmφ is 40R)
　pressure: 400 kgf (1 kgf is 9.8 N.)
　Energizing time: 240 microseconds
　above values that enough are spot weldability excellent large means, in the evaluation shown in Table 3, was evaluated as acceptable or 1.0KA.
[0071]
　(4) ZnO loss test
　punched steel plates of each test example 30 mm?, Superimposed on a SiC furnace pedestal 70 mm × 70 mm, while carrying the SUS304 block of 50 mm × 50 mm × 70 mm heated to 900 ° C., 900 heating standing furnace 6 minutes at ° C., after removal, was immediately quenched sandwich in a stainless steel mold. The Zn deposition amount before and after heating was measured by XRF to measure the Zn deposition amount of Zn in terms were calculated ZnO residual ratio of Zn terms.
　The evaluation shown in Table 3, in Zn residual ratio of 75% or more, 0.40 g / m of Zn remaining amount 2 was passed over.
[0072]
[table 3]

[0073]
　Table 2 As is apparent from, the surface coating layer 107 comprises an organic resin 111, the average particle size of the ZnO particles 109 0.10μm or more and less 5.00, the adhesion amount of the ZnO particles 109 metal Zn converted at 0.5 g / m 2 or more, 10.0 g / m 2 comprises the following, acetylacetonate, surface film layer 107 to more than 10% acetyl acetonate terms are added to 30% the hot-press Al-based plated steel sheet within the scope of the present application (test No. 1 to 10), both, for all four evaluation of the (various characteristics and ZnO loss test), good results have been obtained it can be seen that there.
[0074]
　In contrast, if not contained organic resin 111, or contain a range of acetylacetonate, the average particle size of the ZnO particles 109, any of the deposition amount of the ZnO particles 109 is out of the present application a predetermined range (test No. 11 to 18), for the hot-press Al-based plated steel sheets outside the scope of the present application, both, for at least one of the four evaluation of the (various characteristics and ZnO loss test), good results it can be seen that has not been obtained.
DESCRIPTION OF SYMBOLS
[0075]
　　　100 ... Al-based plated steel sheet
　　　101 ... base material
　　　103 ... Al-based plating layer
　　　107 ... surface film layer
　　　109 ... ZnO particles
　　　111 ... organic resin

The scope of the claims
[Requested item 1]
　And the base material,
　wherein the Al-based plating layer formed on at least one surface of the base material,
　a surface coating layer formed on the Al-based plating layer, and the ZnO particles, and the organic resin, the surface film layer all 10 mass% or more with respect to the mass, and acetylacetonate of 30 wt% or less, as well as containing an average particle size of the ZnO particles, 0.10 .mu.m or more and less 5.00, adhesion of the ZnO particles the amount of metal Zn converted at 0.5 g / m 2 or more, 10.0 g / m 2 or less, and the surface coating layer,
　characterized in that it comprises the, Al-based plated steel sheet for hot press.
[Requested item 2]
　Al-based plated steel sheet according to claim 1, characterized in that on both surfaces of the base material, the Al-based plating layer and the surface coating layer was formed.