CN110114510B - Plated steel sheet for hot pressing, method for producing hot-press formed article, and method for producing vehicle - Google Patents

Plated steel sheet for hot pressing, method for producing hot-press formed article, and method for producing vehicle Download PDF

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Publication number
CN110114510B
CN110114510B CN201780080183.4A CN201780080183A CN110114510B CN 110114510 B CN110114510 B CN 110114510B CN 201780080183 A CN201780080183 A CN 201780080183A CN 110114510 B CN110114510 B CN 110114510B
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steel sheet
zinc
plated steel
based metal
metal soap
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CN201780080183.4A
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CN110114510A (en
Inventor
久保雅宽
中泽嘉明
铃木利哉
野村成彦
藤田宗士
入川秀昭
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/12—Aluminium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
    • C23C28/023—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only
    • C23C28/025—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only with at least one zinc-based layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/02—Stamping using rigid devices or tools
    • B21D22/022—Stamping using rigid devices or tools by heating the blank or stamping associated with heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/208—Deep-drawing by heating the blank or deep-drawing associated with heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/26—Deep-drawing for making peculiarly, e.g. irregularly, shaped articles
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/02—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition
    • C23C18/12—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition characterised by the deposition of inorganic material other than metallic material
    • C23C18/1204—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition characterised by the deposition of inorganic material other than metallic material inorganic material, e.g. non-oxide and non-metallic such as sulfides, nitrides based compounds
    • C23C18/1208—Oxides, e.g. ceramics
    • C23C18/1216—Metal oxides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • C23C2/29—Cooling or quenching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/60—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using alkaline aqueous solutions with pH greater than 8
    • C23C22/66—Treatment of aluminium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
    • C23C28/321—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer with at least one metal alloy layer
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    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
    • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
    • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
    • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer

Abstract

The present invention relates to a plated steel sheet for hot pressing having a plated steel sheet main body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet, and a zinc-based metal soap coating film provided on the surface of the plated steel sheet main body on the aluminum plating layer side in an amount of 7.1 to 19.8g/m in terms of Zn amount2Wherein, in the case of having a zinc oxide film on the surface of the aluminum plating layer in the plated steel sheet body, the total adhesion amount of the zinc oxide film and the zinc-based metal soap film is 7.1 to 19.8g/m in terms of Zn amount2. The present invention also relates to a method for producing a hot press-formed article using the plated steel sheet for hot pressing and a method for producing a vehicle using a press-formed article produced by the method for producing a hot press-formed article.

Description

Plated steel sheet for hot pressing, method for producing hot-press formed article, and method for producing vehicle
Technical Field
The present application relates to a plated steel sheet for hot pressing, a method for producing a hot-press formed article, and a method for producing a vehicle.
Background
In recent years, there has been an increasing demand for suppression of chemical fuel consumption for environmental protection and prevention of global warming, and this demand has affected various manufacturing industries. For example, automobiles which are indispensable as means for movement in daily life and activities are no exception, and improvement in fuel efficiency and the like by weight reduction of the automobile body is required. However, in the case of automobiles, it is not acceptable in terms of product quality to simply reduce the weight of the vehicle body, and it is necessary to ensure appropriate safety.
The structure of an automobile is often formed of iron, particularly steel plate, and it is important to reduce the weight of the steel plate for reducing the weight of the automobile body. However, simply reducing the weight of the steel sheet as described above is not allowed, and it is also required to ensure the mechanical strength of the steel sheet. Such requirements for steel sheets are similar not only in the automobile manufacturing industry but also in various manufacturing industries. Therefore, research and development have been conducted on steel sheets that can maintain or improve the mechanical strength even when the steel sheets are thinner than the steel sheets used in the past by improving the mechanical strength of the steel sheets.
In general, a material having high mechanical strength tends to have a reduced shape fixability in a forming process such as a bending process, and when the material is processed into a complicated shape, the processing itself becomes difficult. One of means for solving the problem concerning the formability is a so-called "hot pressing method (hot pressing method, high-temperature pressing method, press hardening method)". In this hot pressing method, a material to be molded is once heated to a high temperature, and the material softened by heating is press-worked and molded, and then cooled.
According to this hot pressing method, the material is heated to a high temperature once and softened, so that the material can be easily subjected to press working. Therefore, by this hot-pressing, a molded article having both good shape fixability and high mechanical strength can be obtained. In particular, when the material is steel, the mechanical strength of the press-formed product can be improved by the quenching effect due to cooling after forming.
However, when this hot-pressing method is applied to a steel sheet, for example, heating to a high temperature of 800 ℃ or higher oxidizes iron or the like on the surface to generate scale (oxide). Therefore, a step of removing the scale (descaling step) is required after the hot-pressing process, and productivity is lowered. In addition, in the case of a member or the like requiring corrosion resistance, it is necessary to perform rust prevention treatment or metal coating on the surface of the member after processing, and a surface cleaning step and a surface treatment step are required, and productivity is still lowered.
An example of a method for suppressing such a decrease in productivity is a method of coating a steel sheet. In general, various materials such as organic materials and inorganic materials are used as a coating on a steel sheet. Among them, zinc-based plated steel sheets having an alternative anticorrosive action to steel sheets are widely used in automobile steel sheets and the like from the viewpoint of anticorrosive performance and steel sheet production technology. In order to obtain the quenching effect, the heating temperature in the hot press working is targeted to a temperature higher than the Ac3 transformation point of the steel. Namely, the heating temperature is about 700 to 1000 ℃. However, the heating temperature is higher than the decomposition temperature of the organic material, the boiling point of the metal material such as Zn material, or the like. Therefore, when heating for hot pressing, the plating layer on the surface may evaporate, which may cause significant deterioration of surface properties.
Therefore, for example, an Al-based metal-coated steel sheet having a boiling point higher than that of the organic material coating or Zn-based metal coating, so-called aluminum-coated steel sheet, is preferably used as the steel sheet subjected to hot pressing heated to a high temperature.
By coating with Al-based metal, scale can be prevented from adhering to the surface of the steel sheet, and a step such as a descaling step is not required, so that productivity is improved. Further, since the Al-based metal coating also has an anticorrosive effect, the corrosion resistance after coating is also improved. Patent document 1 describes a method of using an aluminum-plated steel sheet obtained by coating a steel having a predetermined steel composition with an Al-based metal for hot-pressing.
However, when the Al-based metal coating is applied, the Al coating is first melted under the condition of preliminary heating before press working in the hot pressing method, and then an Al — Fe compound layer is generated by diffusion of Fe from the steel sheet. The Al-Fe compound layer may grow to the surface of the steel sheet to become an Al-Fe compound layer. This compound layer will be referred to as an alloy layer hereinafter. Since the alloy layer is extremely hard, a processing flaw is formed by contact with a die during press processing.
On the other hand, patent document 2 discloses a method of forming a coating film of a wurtzite compound such as a ZnO coating film on the surface of an aluminum-plated steel sheet for the purpose of improving thermal lubricity and improving chemical conversion treatability and corrosion resistance while preventing the occurrence of processing flaws.
On the other hand, patent document 3 discloses a method of forming a coating of 1 or more Zn compounds selected from the group consisting of Zn hydroxide, Zn phosphate, and Zn organic acid on the surface of an Al-plated steel sheet for the purpose of improving the adhesion of the ZnO coating during press forming. In the method of patent document 2, a ZnO film is formed by heat generated when an aluminum-plated steel sheet having a film of a Zn compound formed thereon is hot-press formed, and a ZnO film having excellent adhesion is formed, so that hot lubricity, film adhesion, spot weldability, and post-coating corrosion resistance can be improved.
Patent document 1: japanese patent laid-open publication No. 2000-38640
Patent document 2: international publication No. 2009/131233
Patent document 3: japanese patent laid-open No. 2014-139350
Disclosure of Invention
Problems to be solved by the invention
Here, the plated steel sheets of patent documents 2 to 3 are excellent in heat soaking lubricity and can suppress the occurrence of processing flaws. However, in general, when hot press forming is performed using a non-plated material or a plated steel sheet, abrasion is generated on a sliding surface of a hot press die on which the plated steel sheet slides, such as a portion of a vertical wall portion or a flange portion of a press formed product. Therefore, as a measure against wear generated on the sliding surface of the die in the high-surface-pressure portion of the hot press molding, die inspection is required. It is expected that the die wear will be reduced by the plated steel sheets of patent documents 2 to 3, but even patent documents 2 to 3 cannot solve the die wear as in other non-plated materials or plated steel sheets.
Accordingly, an object of one embodiment of the present invention is to provide a plated steel sheet for hot pressing that suppresses the occurrence of wear on the sliding surface of a hot pressing die, and a method for manufacturing the same.
Another object of one aspect of the present invention is to provide a method for producing a hot-press formed article in which the occurrence of wear on the sliding surface of a hot-pressing die is suppressed using the plated steel sheet for hot-pressing, and a method for producing a vehicle using a press-formed article produced by the method for producing a hot-press formed article.
Means for solving the problems
The inventors have conducted studies and found the following. When a zinc oxide coating layer (ZnO coating) is formed on the surface of an aluminum plating layer, the surface properties of the aluminum plating layer having projections on the surface are reflected on the surface properties of the zinc oxide coating layer. When an aluminum-plated steel sheet having a zinc oxide film layer formed on the surface thereof slides on the surface of a hot-pressing die, local pressure is applied to the convex portion of the zinc oxide film, which causes abrasion on the sliding surface of the hot-pressing die. The inventors have found that when a zinc oxide film having high smoothness can be formed, the occurrence of wear on the sliding surface of the hot-pressing die can be suppressed.
The subject matter of the present application is as follows.
<1>
A plated steel sheet for hot pressing, comprising:
a plated steel sheet body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet; and
a zinc-based metal soap film provided on the surface of the plated steel sheet body on the side of the aluminum plating layer, wherein the amount of adhesion of the adhesion portion is 7.1 to 19.8g/m in terms of Zn amount2。
<2>
A plated steel sheet for hot pressing, comprising:
a plated steel sheet body having a steel sheet, an aluminum plating layer provided on one or both surfaces of the steel sheet, and a zinc oxide film provided on a surface of the aluminum plating layer; and
a zinc-based metal soap film provided on the surface of the zinc oxide film of the plated steel sheet body,
the amount of the zinc oxide film and the zinc-based metal soap film adhering to the total adhering portion is 7.1 to 19.8g/m in terms of Zn amount2。
<3>
The plated steel sheet for hot pressing according to <2>, wherein at least half of an adhesion amount of an adhesion portion of the zinc oxide film and the zinc-based metal soap film in total is an adhesion amount of an adhesion portion of the zinc-based metal soap film.
<4>
The plated steel sheet for hot pressing according to any one of <1> to <3>, wherein the zinc-based metal soap coating film is a coating film of at least one zinc-based metal soap selected from the group consisting of zinc dioctoate, zinc octoate, zinc laurate and zinc stearate.
<5>
A plated steel sheet for hot pressing, comprising:
a plated steel sheet body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet; and
a zinc oxide film provided on the surface of the plated steel sheet body on the side of the aluminum plating layer,
the maximum value of skewness Rsk (skewness) of the roughness curve of the surface of the zinc oxide film is less than 0.
<6>
A method for manufacturing a plated steel sheet for hot pressing, comprising the steps of: the surface of the plated steel sheet body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet on the aluminum plating layer side is 7.1 to 19.8g/m in terms of Zn amount in terms of the amount of deposit of a deposit portion2The zinc-based metal soap film is formed.
<7>
A method for manufacturing a plated steel sheet for hot pressing, comprising the steps of: on the surface of the zinc oxide film of a plated steel sheet body having a steel sheet, an aluminum plating layer provided on one or both surfaces of the steel sheet, and a zinc oxide film provided on the aluminum plating layer, the amount of adhesion of the adhesion portion in terms of Zn amount, which is the sum of the amount of adhesion of the zinc oxide film and the amount of adhesion of the adhesion portion, is 7.1 to 19.8g/m2The zinc-based metal soap film is formed.
<8>
The method of manufacturing a plated steel sheet for hot pressing <7>, wherein in the step of forming the zinc-based metal soap film, at least half of an adhesion amount of an adhesion portion of the total of the zinc oxide film and the zinc-based metal soap film is set as an adhesion amount of an adhesion portion of the zinc-based metal soap film.
<9>
The method of producing a plated steel sheet for hot pressing according to any one of <6> to <8>, which comprises a step of heating the zinc-based metal soap film at 300 ℃ or higher to form a zinc oxide film.
<10>
The method of manufacturing a plated steel sheet for hot pressing <9>, wherein a maximum value of a skewness Rsk of a roughness curve of a surface of the zinc oxide film formed by heating the zinc-based metal soap film is less than 0.
<11>
The method for producing a plated steel sheet for hot pressing as set forth in any one of <6> to <10>, wherein the zinc-based metal soap coating film is a coating film of at least one zinc-based metal soap selected from the group consisting of zinc dioctoate, zinc octoate, zinc laurate and zinc stearate.
<12>
A method for manufacturing a hot press molded article, comprising the steps of:
a step of manufacturing a plated steel sheet for hot pressing by the method for manufacturing a plated steel sheet for hot pressing according to any one of <6> to <11>, wherein the step of forming the zinc-based metal soap coating film forms at least the zinc-based metal soap coating film on a surface of the plated steel sheet body on the side of the aluminum plating layer, the surface being in contact with a sliding surface of a hot-pressing die in a subsequent hot-pressing step, thereby manufacturing the plated steel sheet for hot pressing; and
and a hot-pressing step of hot-press forming the plated steel sheet for hot-pressing.
<13>
A method for producing a hot press-formed article, comprising hot press-forming a plated steel sheet for hot pressing produced by the method for producing a plated steel sheet for hot pressing of <10 >.
<14>
A method for manufacturing a vehicle, comprising attaching a press-molded article manufactured by the method for manufacturing a hot press-molded article according to <12> or <13> to a surface having a zinc oxide film, the surface facing the outside of the vehicle.
Effects of the invention
According to one embodiment of the present application, a plated steel sheet for hot pressing and a method for manufacturing the same can be provided, in which the occurrence of wear on the sliding surface of a hot pressing die is suppressed.
Further, according to an aspect of the present invention, it is possible to provide a method for producing a hot press-formed article in which the occurrence of scratches on the sliding surface of a hot press die is suppressed using the plated steel sheet for hot pressing, and a method for producing a vehicle using a press-formed article produced by the method for producing a hot press-formed article.
Drawings
Fig. 1A is a schematic cross-sectional view showing an example of a plated steel sheet for hot pressing according to the present embodiment.
Fig. 1B is a schematic cross-sectional view showing a state in which the plated steel sheet for hot pressing according to the present embodiment is in contact with a die.
Fig. 2A is a schematic cross-sectional view showing an example of a conventional plated steel sheet for hot pressing.
Fig. 2B is a schematic cross-sectional view showing a state in which a conventional plated steel sheet for hot pressing is in contact with a die.
Fig. 3 is a process diagram showing an example of a typical process from the production of a plated steel sheet to hot press forming.
Fig. 4 is a schematic configuration diagram of an evaluation apparatus for thermal lubricity.
Detailed Description
Next, an embodiment as an example of the present application will be described in detail.
Hereinafter, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings.
In the present specification and the drawings, the same reference numerals are used to designate the components having substantially the same functional configuration, and the redundant description may be omitted.
The numerical range indicated by the term "to" means a range including numerical values described before and after the term "to" as a lower limit value and an upper limit value.
The term "step" is used to include not only an independent step but also a step that can achieve the intended purpose of the step if it cannot be clearly distinguished from other steps.
< plated steel sheet >
A plated steel sheet according to an embodiment of the present application will be described.
The plated steel sheet for hot pressing according to the present embodiment (hereinafter also referred to as "plated steel sheet") has a plated steel sheet main body having a steel sheet and an aluminum plating layer (hereinafter also referred to as "Al plating layer") provided on one or both surfaces of the steel sheet, and a zinc-based metal soap coating film provided on the Al plating layer of the plated steel sheet main bodyThe amount of the deposit on the side surface is 7.1 to 19.8g/m in terms of Zn amount2。
In the plated steel sheet according to the present embodiment, the plated steel sheet body may have a zinc oxide film (hereinafter, also referred to as "ZnO film") provided on the Al plating layer. Wherein, when the plated steel sheet body has a ZnO film, the amount of adhesion of the ZnO film and the zinc-based metal soap film at the total adhesion portion is set to 7.1 to 19.8g/m in terms of Zn amount2。
With the above configuration, the plated steel sheet according to the present embodiment suppresses the occurrence of wear on the sliding surface of a hot press die (hereinafter also referred to as "die") during hot press forming. The plated steel sheet according to the present embodiment is found from the following findings.
First, the following was confirmed by analyzing a press-formed product and a die obtained by hot press forming a plated steel sheet (a plated steel sheet having a ZnO film formed on an Al plating layer) of patent document 2. In the plated steel sheet of patent document 2, the ZnO film has a convex portion along the surface property of the Al plating layer (see fig. 2A: in fig. 2A, 12 denotes a steel sheet, 14 denotes an Al plating layer, and 16 denotes a ZnO film.). When the plated steel sheet is hot-press formed, local surface pressure is applied to the convex portion of the ZnO film from the sliding surface sliding on the die, so that the top of the convex portion of the ZnO film is peeled off, and the Al plating layer is exposed. In addition, a substance caused by the mold adheres to the vicinity of the exposed Al plating layer. From this, it was found that Al of the exposed Al plating layer reacts with Fe of the mold to generate an intermetallic compound, and the sliding surface of the mold was abraded.
That is, the following was found. 1) In the plated steel sheet of patent document 2, since a thin ZnO film is formed on the Al plating layer, the maximum value of the skewness Rsk of the roughness curve of the surface exceeds 0, and a convex portion protruding from the surface is formed. 2) The protrusions protruding from the surface make point contact with the mold. 3) When the pressing pressure of the hot press molding is increased, a high surface pressure is generated in the convex portion of the surface, and the sliding surface of the mold is worn (see fig. 2B: in fig. 2B, 12 denotes a steel sheet, 14 denotes an Al plating layer, 16 denotes a ZnO coating, and 26 denotes a die. ).
Then, the inventors found that the following method is effective in suppressing wear of the sliding surface of the mold. 1) In order to improve the smoothness of the ZnO film, a lubricant is applied. 2) In consideration of chemical conversion treatability and corrosion resistance after hot press forming, zinc-based metal soap containing Zn is used as a lubricant. Specifically, the inventors have found the following.
Since zinc-based metal soap is used for a lubricant, when the amount of zinc-based metal soap deposited is increased, it is less likely to be affected by the surface properties of the underlying plated steel sheet body (Al plating layer or ZnO film), and a zinc-based metal soap film having high smoothness can be formed (see fig. 1A: fig. 1A, in which 10 denotes a plated steel sheet, 10A denotes a plated steel sheet body, 12 denotes a steel sheet, 14 denotes an Al plating layer, 16 denotes a ZnO film, and 18 denotes a zinc-based metal soap film). The zinc-based metal soap film is oxidized by heating before pressurization in hot press molding, and organic substances other than zinc (fatty acid and the like) are decomposed, resulting in a ZnO film. That is, during the pressing of the hot press forming, a ZnO film having high smoothness (for example, a ZnO film having a maximum value of skewness Rsk of a roughness curve of the surface of less than 0) is formed on the surface of the plated steel sheet. The zinc-based metal soap film may be heated to form a ZnO film before hot press molding.
Since the ZnO coating on the outermost surface of the plated steel sheet is smooth, the surface pressure applied to the ZnO coating from the sliding surface that slides on the die is reduced when the plated steel sheet is hot-press formed. That is, the ZnO film of the plated steel sheet comes into surface contact with the sliding surface of the mold, the actual contact area between the ZnO film of the plated steel sheet and the sliding surface of the mold increases, and the contact surface pressure is reduced. Therefore, the peeling of the ZnO film is suppressed (see FIG. 1B, in FIG. 1B, 10 denotes a plated steel sheet, 10A denotes a plated steel sheet main body, 12 denotes a steel sheet, 14 denotes an Al plating layer, 16 denotes a ZnO film, 18A denotes a ZnO film formed of a zinc-based metal soap film, and 26 denotes a die.). Since the peeling of the ZnO coating is suppressed, the formation of intermetallic compounds due to the reaction occurring in contact with the Al plating layer can be suppressed. As a result, the generation of intermetallic compounds causing the wear of the die is suppressed, and therefore, the wear of the sliding surface of the die on which the plated steel sheet slides is suppressed.
From the above findings, the inventors have found that the plated steel sheet according to the present embodiment is configured as described above, and thereby suppresses the occurrence of wear on the sliding surface of the hot press die during hot press forming.
The inventors have also found the following. The ZnO coating formed of the zinc-based metal soap coating of the plated steel sheet according to the present embodiment is less likely to peel off during and after hot press forming, and is less likely to cause abrasion of the die. Therefore, a molded article having high chemical conversion treatability, excellent adhesion between the Al plating layer and the ZnO film after molding, and high corrosion resistance (i.e., corrosion resistance after coating) can be obtained with high mass productivity.
Hereinafter, the plated steel sheet according to the present embodiment will be described in detail.
< plated steel sheet body >
The plated steel sheet body has a steel sheet and an Al plating layer provided on one or both surfaces of the steel sheet. The plated steel sheet body may have a ZnO coating provided on the Al plating layer.
(Steel plate)
As the steel sheet (steel sheet before plating), for example, a steel sheet formed so as to have high mechanical strength (for example, various properties relating to mechanical deformation and fracture such as tensile strength, yield point, elongation, drawing, hardness, impact value, fatigue strength, creep strength) is preferably used. An example of a steel sheet (steel sheet before plating) that achieves high mechanical strength for use in the plated steel sheet according to the present embodiment is as follows. In addition,% represents% by mass unless otherwise specified.
The steel sheet preferably contains, in mass%, C: 0.1 to 0.6%, Si: 0.01-0.6%, Mn: 0.5-3%, Ti: 0.01 to 0.1% and B: 0.0001-0.1%, and the balance of Fe and impurities.
C is contained to secure the target mechanical strength. If C is less than 0.1%, the mechanical strength cannot be sufficiently improved, and the effect of containing C is insufficient. On the other hand, if C exceeds 0.6%, the steel sheet can be further hardened, but melt cracking tends to occur. Therefore, the C content is preferably set to 0.1% or more and 0.6% or less.
Si is one of strength-improving elements for improving mechanical strength, and is contained to secure a target mechanical strength as in C. When Si is less than 0.01%, the strength-improving effect is hardly exhibited, and sufficient improvement in mechanical strength cannot be obtained. On the other hand, Si is also an oxidizable element. Therefore, when Si exceeds 0.6%, wettability may be reduced and no plating may occur when hot dip aluminum plating is performed. Therefore, the Si content is preferably set to 0.01% or more and 0.6% or less.
Mn is one of the strengthening elements for strengthening steel and also one of the elements for improving hardenability. Further, Mn is also effective for preventing hot shortness due to S, which is one of impurities. When the Mn content is less than 0.5%, these effects cannot be obtained, and when the Mn content is 0.5% or more, the above effects are exhibited. On the other hand, if Mn exceeds 3%, the residual γ phase may become too much and the strength may decrease. Therefore, the Mn content is preferably set to 0.5% or more and 3% or less.
Ti is one of the strength-enhancing elements and also an element for improving the heat resistance of the Al plating layer. When Ti is less than 0.01%, the strength-improving effect and the oxidation resistance-improving effect cannot be obtained, and when Ti is 0.01% or more, these effects are exhibited. On the other hand, if Ti is contained excessively, for example, carbide or nitride may be formed to soften the steel. Particularly, when Ti exceeds 0.1%, the target mechanical strength is likely to be not obtained. Therefore, the Ti content is preferably set to 0.01% or more and 0.1% or less.
B has an effect of acting during quenching to improve strength. In the case where B is less than 0.0001%, such an intensity-improving effect is low. On the other hand, if B exceeds 0.1%, inclusions may be formed, resulting in embrittlement and a decrease in fatigue strength. Therefore, the B content is preferably set to 0.0001% or more and 0.1% or less.
The steel sheet may contain other impurities mixed in through a manufacturing process or the like.
The steel sheet formed with such a chemical composition can have a mechanical strength of about 1500MPa or more by being quenched by heating by a hot press method or the like. In spite of such a steel sheet having high mechanical strength, when it is processed by a hot pressing method, it can be hot pressed in a state softened by heating, and therefore it can be easily formed. In addition, the steel sheet can achieve high mechanical strength, and can maintain or improve mechanical strength even when the steel sheet is made thin for weight reduction.
(Al plating)
The Al plating layer is formed on one or both surfaces of the steel sheet before plating. The Al plating layer is formed on one surface or both surfaces of the steel sheet by, for example, hot dip plating, but the forming method is not limited thereto.
The composition of the Al plating layer may be 50% or more of Al. Elements other than Al are not particularly limited, but Si may be positively contained for the following reason.
When Si is contained, an Al — Fe — Si alloy layer is formed at the interface between the plating layer and the base metal, and the formation of a brittle Al — Fe alloy layer formed during hot dip plating can be suppressed. If Si is less than 3%, the Al — Fe alloy layer grows thick at the stage of aluminum plating, and cracking of the plating layer may be promoted during processing, which may adversely affect the corrosion resistance. On the other hand, if Si exceeds 15%, the volume fraction of the layer containing Si may increase, and the workability and corrosion resistance of the plating layer may decrease. Therefore, the Si content in the Al plating layer is preferably set to 3 to 15%.
The Al plating prevents corrosion of the steel sheet. In addition, when the plated steel sheet is processed by a hot pressing method, the Al plating layer does not oxidize and generate scale (iron oxide) on the surface even when heated to a high temperature. By preventing the scale from being generated by the Al plating layer, the step of removing the scale, the step of surface cleaning, the step of surface treatment, and the like can be omitted, and the productivity of the molded article can be improved. The Al plating layer has a higher boiling point and a higher melting point than a plating layer made of an organic material and a plating layer made of another metal material (for example, a Zn material). Therefore, since the plating layer does not evaporate when formed by hot press forming, hot press forming at a high temperature becomes possible. Therefore, the formability in the hot press forming can be further improved, and the forming can be easily performed.
The Al plating layer can be alloyed with Fe in the steel sheet by heating at the time of hot dip plating and at the time of hot pressing. Therefore, the Al plating layer is not necessarily limited to a single layer having a constant composition of components, and includes an Al plating layer of a partially alloyed layer (alloy layer).
(ZnO coating film)
A ZnO coating (coating containing ZnO) is formed on the surface of the Al plating layer of the plated steel sheet body as necessary. In particular, when a zinc-based metal soap film is formed on a part of the Al plating layer side surface of the plated steel sheet main body, the ZnO film is preferably formed on the entire Al plating layer of the plated steel sheet main body. In the region where the ZnO film becomes the outermost layer of the plated steel sheet, the ZnO film can impart thermal lubricity, chemical conversion treatability, and corrosion resistance to the plated steel sheet.
The method for forming the ZnO coating is not particularly limited, and for example, the ZnO coating can be formed on the Al plating layer by the methods described in patent documents 1 and 2.
The amount of the ZnO film adhering to the portion (hereinafter, also simply referred to as "adhering amount") is preferably set to 0.5 to 7g/m in terms of Zn amount per surface of the steel sheet2. The amount of the ZnO film deposited was 0.5g/m in terms of Zn amount2In the above case, the lubrication enhancing effect can be effectively exhibited in the region of contact with the outside of the sliding surface of the die during hot press forming. On the other hand, the amount of ZnO film deposited exceeds 7g/m in terms of Zn amount2In the case of (3), the thickness of the Al plating layer and the ZnO film may be too large, and weldability and paint adhesion may be deteriorated.
The amount of the ZnO film is particularly preferably 1 to 4g/m in terms of Zn amount per surface of the steel sheet2On the other hand, in the hot press molding, lubricity at the time of hot pressing can be secured also in the region in contact with the outside of the sliding surface of the die, and further weldability and paint adhesion are also improved.
As a method for measuring the amount of ZnO film deposited, a fluorescent X-ray method was used. Specifically, a calibration curve was prepared by using several types of standard samples in which the deposition amount of the ZnO film (converted in Zn amount) was known by a fluorescent X-ray method, and the deposition amount of the ZnO film was determined by converting the Zn intensity of the sample to be measured into the deposition amount of the ZnO film.
< zinc-based Metal soap film >
A zinc-based metal soap coating (a coating containing a zinc-based metal soap) is provided on the Al-plating-layer-side surface of the plated steel sheet body. Specifically, when no ZnO coating is provided on the Al plating layer of the plated steel sheet body, a zinc-based metal soap coating is provided on the surface (entire surface) of the Al plating layer. On the other hand, when a ZnO film is provided on the Al plating layer of the plated steel sheet body, a zinc-based metal soap film is provided on at least a part of the surface of the ZnO film.
Examples of the metal soap of the zinc-based metal soap film include metal salts (zinc salts of fatty acids) of zinc and a fatty acid (for example, a fatty acid having 7 to 20 carbon atoms). The fatty acid may be either a saturated fatty acid or an unsaturated fatty acid.
In particular, from the viewpoint of forming a zinc-based metal soap film having high smoothness, the metal soap of the zinc-based metal soap film is preferably a metal soap which is liquid at room temperature (25 ℃).
Specific examples of the zinc-based metal soap coating include, for example, a coating of at least one zinc-based metal soap selected from the group consisting of zinc dioctoate, zinc octoate, zinc laurate and zinc stearate.
The zinc-based metal soap coating film is formed using a zinc-based metal soap for use as a lubricant, and therefore has high smoothness. On the other hand, the zinc-based metal soap film is oxidized by heating at 300 ℃ or higher (heating before pressurization in hot press molding or heating before hot press molding), and organic substances other than zinc (fatty acid and the like) are decomposed to form a ZnO film. That is, the region of the plated steel sheet body on which the zinc-based metal soap film is provided is heated to become a region coated with a ZnO film derived from the zinc-based metal soap film.
Further, by heating the zinc-based metal soap film having high smoothness, a ZnO film having high smoothness (for example, a ZnO film in which the maximum value of the skewness Rsk of the roughness curve of the surface satisfies Rsk <0) can be formed. The ZnO film having high smoothness suppresses wear of the sliding surface of the die on which the plated steel sheet slides when the plated steel sheet is hot-pressed.
Here, in the case where the plated steel sheet body does not have a ZnO film (that is, in the case where a zinc-based metal soap film is formed on the surface of the Al plating layer of the plated steel sheet body), the amount of adhesion of the adhesion portion of the zinc-based metal soap film is affected by the surface properties of the underlying plated steel sheet body (Al plating layer) regardless of whether the amount is too small or too large, and the smoothness of the zinc-based metal soap film and the smoothness of the ZnO film formed of the zinc-based metal soap film are reduced. Therefore, the amount of Zn-based metal soap film adhering to the portion (hereinafter, also simply referred to as "adhering amount") is set to 7.1 to 19.8g/m in terms of Zn amount2Preferably 8.82 to 16.3g/m2. The amount of the deposit may be 8.9 to 19.8g/m in terms of Zn amount2、9.2～19.8g/m2Or 9.5 to 19.8g/m2Any range of (1).
On the other hand, in the case where the plated steel sheet main body has a ZnO film (that is, in the case where a zinc-based metal soap film is formed on the surface of the ZnO film of the plated steel sheet main body), the amount of the zinc-based metal soap film to be deposited needs to be considered so that the surface of the ZnO film becomes smooth in both the ZnO film of the underlying plated steel sheet main body and the ZnO film formed of the zinc-based metal soap film. Therefore, the amount of the zinc-based metal soap coating added to the total amount of the ZnO coating of the plated steel sheet body (the total amount of the ZnO coating and the zinc-based metal soap coating of the plated steel sheet body) is set to 7.1 to 19.8g/m in terms of Zn amount2Preferably 8.82 to 16.3g/m2. The amount of the deposit may be 8.9 to 16.3g/m in terms of Zn amount2、9.2～16.3g/m2Or 9.5 to 16.3g/m2Any range of (1).
In the case where the plated steel sheet body has a ZnO film (that is, in the case where a zinc-based metal soap film is formed on the surface of the ZnO film of the plated steel sheet body), from the viewpoint of improving the smoothness of the surface of the ZnO film formed of the zinc-based metal soap film, it is preferable to set the adhesion amount of the zinc-based metal soap film to be equal to or more than half of the total adhesion amount of the ZnO film and the zinc-based metal soap film.
As a method for measuring the amount of adhesion of the zinc-based metal soap coating, for example, a fluorescent X-ray method is used. Specifically, a calibration curve was prepared by using several kinds of standard samples in which the amount of adhesion of the zinc-based metal soap film (in terms of Zn amount) was known by a fluorescent X-ray method, and the amount of adhesion of the zinc-based metal soap film was obtained by converting the Zn intensity of the sample to be measured into the amount of adhesion of the zinc-based metal soap film.
Here, the zinc-based metal soap film is preferably formed on at least a surface of the Al-plated side of the plated steel sheet body, which is in contact with the sliding surface of the hot-pressing die.
Specifically, for example, when a ZnO coating is formed on an Al plating layer of a plated steel sheet main body, a zinc-based metallic soap coating is preferably formed at least on the surface of the plated steel sheet (Al plating layer or ZnO coating of the plated steel sheet main body) which becomes the vertical wall portion and flange portion of the press-formed product obtained when the plated steel sheet is hot press-formed by a hot press die. This is due to: the plated steel sheet at the portions of the vertical wall portion and the flange portion of the press-formed article is a region where abrasion is likely to occur in the die because the surface is a portion formed while sliding in the die (for example, "fixing portion and shoulder portion of the retained steel sheet" in the upper die, "fixing portion and shoulder portion of the retained steel sheet" in the lower die) (see fig. 3 (8)).
On the other hand, when no ZnO coating is formed on the Al plating layer of the plated steel sheet body, the zinc-based metallic soap coating is preferably formed on the entire surface of the Al plating layer.
The plated steel sheet according to the present embodiment described above may be used for hot press forming while having a zinc-based metal soap film, or may be used for hot press forming while a zinc-based metal soap film is heated in advance to form a ZnO film.
That is, the plated steel sheet according to the present embodiment may be used for hot press forming by being produced as a hot-press plated steel sheet having a plated steel sheet body having a steel sheet and an Al plating layer provided on one or both surfaces of the steel sheet, and a ZnO film provided on the surface of the plated steel sheet body on the Al plating layer side, and the maximum value of the skewness Rsk of the roughness curve of the surface of the ZnO film being lower than 0.
Here, the skewness Rsk of the roughness curve was measured in accordance with JIS B0601 (2001). Specifically, the skewness Rsk of the roughness curve was measured under the following measurement conditions in accordance with IS B0601 (2001).
Determination of conditions
A measuring device: "surface roughness/contour shape measuring machine Formtracer" manufactured by Mitutoyo, Ltd "
Measurement length L: 9.6mm
Cutoff wavelength λ c: 0.8mm
Stylus tip shape: cone with 60 degree front end angle
Stylus tip radius: 2 μm
Measuring speed: 1mm/sec
Here, the skewness Rsk of the roughness curve is defined by JIS B0601 (2001), and is an index representing symmetry of a peak portion and a valley portion with respect to an average line of the roughness curve. When Rsk is positive (0< Rsk), the peaks and valleys are shifted downward from the average line of the roughness curve. On the other hand, when Rsk is negative (Rsk <0), the peaks and valleys are shifted upward from the average line of the roughness curve. That is, when Rsk is negative (Rsk <0), the number of hills protruding from the surface is small, and the smoothness is high.
If the Rsk value is partially positive, a protruding convex portion is present on a part of the surface of the hot-pressing plated steel sheet. That is, the surface pressure of the convex portion of the surface against the sliding surface of the mold becomes relatively high, and the sliding surface of the mold is easily worn. Therefore, the maximum value of Rsk on the surface of the ZnO film is preferably set to less than 0. By setting the maximum value of Rsk on the surface of the ZnO film to be less than 0, uniform surface contact between the surface of the ZnO film and the sliding surface of the mold can be achieved, the effective surface pressure at the time of sliding of the mold can be reduced, and abrasion of the sliding surface of the mold can be suppressed.
< method for producing plated steel sheet for hot pressing >
The method for producing a plated steel sheet according to the present embodiment includes a step of forming a zinc-based metal soap coating on the surface of the plated steel sheet body on the Al plating layer side.
Specifically, for example, when no ZnO film is provided on the Al plating layer of the plated steel sheet main body, the method for producing a plated steel sheet includes a step of forming a zinc-based metal soap film on the surface of the Al plating layer. On the other hand, when a ZnO film is provided on the Al plating layer of the plated steel sheet main body, the method for producing a plated steel sheet includes a step of forming a zinc-based metal soap film on at least a part of the surface of the ZnO film.
In addition, when the plated steel sheet body does not have a ZnO film (that is, when a zinc-based metal soap film is formed on the surface of the Al plating layer of the plated steel sheet body), the amount of the zinc-based metal soap film deposited is set to 7.1 to 19.8g/m in terms of Zn amount2Preferably 8.82 to 16.3g/m2。
On the other hand, when the plated steel sheet body has a ZnO film (that is, when a zinc-based metal soap film is formed on the surface of the ZnO film of the plated steel sheet body), the total adhesion amount of the zinc-based metal soap film (the total adhesion amount of the ZnO film and the zinc-based metal soap film of the plated steel sheet body) added to the adhesion amount of the ZnO film of the plated steel sheet body is set to 7.1 to 19.8g/m in terms of Zn amount2Preferably 8.82 to 16.3g/m2. However, from the viewpoint of improving the smoothness of the surface of the ZnO film formed of the zinc-based metal soap film, it is preferable to set the adhesion amount of the zinc-based metal soap film to be equal to or more than half of the total adhesion amount of the ZnO film and the zinc-based metal soap film.
In the step of forming the zinc-based metal soap film, the zinc-based metal soap itself is applied by a known application apparatus such as a spray coater, a roll coater, or a die coater, thereby forming the zinc-based metal soap film. Further, a zinc-based metal soap film may be formed by using a sponge, an electrostatic oiling device, or the like. The viscosity of the zinc-based metal soap may be adjusted by an organic solvent during coating. After the zinc-based metal soap is applied, the zinc-based metal soap coating film is dried at 300 ℃ or higher and 2 minutes or higher as necessary, for example, to form a zinc-based metal soap coating film.
Here, in the step of forming the zinc-based metal soap film, the type of the zinc-based metal soap and the region where the zinc-based metal soap film is formed are as described above.
The method for producing a plated steel sheet according to the present embodiment may further include a step of heating the zinc-based metal soap film at 300 ℃ or higher to form a ZnO film. That is, the zinc of the zinc-based metal soap film may be oxidized by heating, and organic substances (fatty acids and the like) other than zinc may be decomposed to form a ZnO film (for example, a ZnO film having a surface roughness curve whose skewness Rsk satisfies Rsk <0), and the resulting plated steel sheet may be used for hot press forming.
The heating for forming the zinc-based metal soap film into a ZnO film is preferably performed at 300 ℃ or more and 2 minutes or more.
< method for producing Hot Press molded article >
The method for producing a hot press-formed article according to the present embodiment is a method for producing a formed article by hot press-forming the plated steel sheet according to the present embodiment.
Specifically, for example, in the method for producing a plated steel sheet according to the present embodiment, at least a zinc-based metal soap film is formed on a surface of the plated steel sheet body on the side of the Al plating layer, which is in contact with the sliding surface of the hot-pressing die, through the step of forming the zinc-based metal soap film, and then the produced plated steel sheet for hot-pressing is hot-press molded. In this case, after the zinc-based metal soap film of the plated steel sheet becomes a ZnO film by heating before pressing, the plated steel sheet is pressed.
For example, in the method for producing a hot press-formed product, a plated steel sheet produced in the method for producing a plated steel sheet according to the present embodiment through a step of heating a zinc-based metal soap film at 300 ℃.
In the method of manufacturing a hot press molded product according to the present embodiment, the hot press molding method is, for example, punching (blanking) as needed, and then heating to a high temperature to soften the plated steel sheet. Then, the softened plated steel sheet is pressed and formed using a die, and then cooled. In this manner, in the hot press forming, the plated steel sheet is once softened, whereby the subsequent pressing can be easily performed. The press-molded article after hot press molding is quenched by heating and cooling to obtain a molded article having a high tensile strength of about 1500MPa or more.
As a heating method in the hot press molding, a heating method using infrared heating, energization heating, induction heating, or the like can be employed in addition to a normal electric furnace or radiant tube furnace.
When the Al plating layer of the plated steel sheet is heated to a temperature not lower than the melting point, the Al plating layer melts and, at the same time, the Al phase changes into an Al — Fe alloy phase and an Al — Fe — Si alloy phase by interdiffusion with Fe. The melting points of the Al-Fe alloy phase and the Al-Fe-Si alloy phase are about 1150 ℃. There are many kinds of intermetallic compounds contained in the Al — Fe alloy phase and the Al — Fe — Si alloy phase, and when the alloy is heated at a high temperature or for a long time, the alloy phase changes to an alloy phase having a higher Fe concentration.
The state of the Al plating layer which is preferable as the press-formed article is a state of being alloyed to the surface and a state of not having a high Fe concentration in the alloy phase. If Al remains unalloyed, only this portion is rapidly corroded, and corrosion resistance after coating deteriorates, so that the coating film is extremely likely to swell, which is not preferable. On the other hand, if the Fe concentration in the alloy phase becomes too high, the corrosion resistance of the alloy phase itself is lowered, the corrosion resistance after coating is deteriorated, and the coating film is likely to swell. That is, the corrosion resistance of the alloy phase depends on the Al concentration in the alloy phase. Therefore, in order to improve the corrosion resistance after coating, the alloyed state is controlled by the amount of Al deposited and the heating condition.
In the heating method in the hot press forming, the average temperature rise rate in a temperature range from 50 ℃ to a temperature 10 ℃ lower than the maximum plate temperature is preferably set to 10 to 300 ℃/sec. The average temperature rise rate affects the productivity in hot press forming of the plated steel sheet. If the average rate of temperature rise is less than 10 ℃/sec, it takes time to soften the hot-press plated steel sheet. On the other hand, if the temperature exceeds 300 ℃, although softening is rapid, alloying of the Al plating layer may become a cause of pulverization. The average temperature rise rate is generally about 5 ℃/sec in the case of heating in an atmosphere. The average temperature rise rate of 100 ℃/sec or more can be achieved by electric heating or high-frequency induction heating.
On the other hand, since hot press forming is required in the austenite single phase region for the maximum reaching plate temperature, a temperature of about 900 to 950 ℃ is generally used in many cases. In hot press forming, the maximum reaching plate temperature is not particularly limited, but when it is less than 850 ℃, it is difficult to obtain sufficient quench hardness, which is not preferable. In addition, the Al plating layer also needs to be made into an Al-Fe alloy phase. From these viewpoints, the maximum reaching plate temperature is preferably set to 850 ℃ or higher. On the other hand, when the maximum plate temperature exceeds 1000 ℃, the alloying excessively proceeds, and the Fe concentration in the Al — Fe alloy phase increases, which may cause a decrease in the corrosion resistance after coating. From these viewpoints, the upper limit of the maximum reached plate temperature is not limited to all because it depends on the temperature increase rate and the amount of Al deposited, but it is also preferable to set the maximum reached plate temperature to 1100 ℃.
In hot press forming, a plated steel sheet heated to a high temperature is press-formed by a die. Thereafter, the molded article is cooled to obtain a press-molded article having a desired shape.
Here, an example of a general process from the production of the plated steel sheet to the hot press forming is as follows.
First, Al plating is formed on one or both surfaces of a steel sheet (FIG. 3 (1): 12 in FIG. 3) or (FIG. 3 (2): 14 in FIG. 3).
Next, a ZnO film was formed on the surface of the Al plating layer (FIG. 3 (3): 16 in FIG. 3 represents a ZnO film.)
Next, the obtained plated steel sheet is wound into a coil shape (fig. 3 (4): 20 in fig. 3 shows a plated steel sheet (plated steel sheet body in the present embodiment)) wound into a coil shape.
Subsequently, the plated steel sheet wound into a coil form is drawn out and punched (blanking process) (FIGS. 3(5) to 3 (6): 22 in FIG. 3 shows a blank).
Next, the ingot is heated by a heating furnace (FIGS. 3 and 7: 24 in FIG. 3 represents a heating furnace).
Then, the heated blank is pressed by a pair of dies of an upper die and a lower die to be formed and quenched (fig. 3(8), 26A in fig. 3 shows the upper die, and 26B shows the lower die).
Then, the molded article was removed from the mold to obtain a target press-molded article (FIGS. 3 and 9: 28 in FIG. 3 shows a press-molded article)
On the other hand, in the usual steps from the production of the plated steel sheet to the hot press forming, the zinc-based metal soap film is formed in each step or between the steps after the Al plating layer is formed and before the plated steel sheet (blank material) is heated. Specifically, regarding the zinc-based metal soap coating, 1) after the Al plating layer is formed, the zinc-based metal soap coating may be formed on the surface of the Al plating layer formed on the plated steel sheet body (e.g., a blank after punching) (note that, in the case where the zinc-based metal soap coating is formed on the entire surface of the Al plating layer, the formation of the ZnO coating may be omitted. ) (ii) a Or 2) after the ZnO film is formed, a zinc-based metal soap film is formed on the surface of the ZnO film of the plated steel sheet body (e.g., punched blank).
The zinc-based metal soap film is preferably formed on the entire surface of the Al plating layer or the ZnO film, but may be formed on a surface that contacts the sliding surface of the hot-pressing die. The surface of the plated steel sheet in contact with the sliding surface of the hot-pressing die is, for example, the surface of the plated steel sheet (Al plating layer or ZnO coating film of the plated steel sheet body) which is to be the vertical wall portion and the flange portion of the obtained press-formed product. Specifically, for example, the surfaces of the plated steel sheet that contact the sliding surfaces of the hot-pressing die are the surfaces of the plated steel sheet (plated steel sheet body) that contact the "fixing portion and shoulder portion of the retained steel sheet" in the upper die and the "fixing portion and shoulder portion of the retained steel sheet" in the lower die (see fig. 3 (8): 26a1 in fig. 3 represents the fixing portion of the upper die, 26a2 represents the shoulder portion of the upper die, 26B1 represents the fixing portion of the lower die, and 26B2 represents the shoulder portion of the lower die).
The heating of the plated steel sheet before pressing may be performed directly as a zinc-based metal soap coating or may be performed after forming the zinc-based metal soap coating into a ZnO coating.
< method for manufacturing vehicle >
Various press-molded articles can be produced by the hot press molding method according to the present embodiment. In addition, the surface of the produced press-molded article on which the ZnO film is formed is particularly excellent in corrosion resistance (i.e., coating corrosion resistance). Therefore, when a press-molded article for a vehicle is manufactured, it is preferable to manufacture a vehicle by mounting the manufactured press-molded article with the surface having the ZnO film facing the outside of the vehicle.
Specifically, for example, a press-formed article (for example, a center pillar outer, a door outer, a roof side rail outer, a side panel, a fender, etc.) exposed when mounted on a vehicle is manufactured by the hot press forming method according to the present embodiment. When these press-molded articles are mounted on a vehicle, the press-molded articles are mounted on the vehicle such that the "surface on which the ZnO film is formed" faces the outside of the vehicle (for example, such that the press-molded articles are exposed from the vehicle).
Examples
The present application will be further described below with reference to examples. The present application is not limited to the following examples.
< comparative examples 1 to 4>
Both surfaces of cold rolled steel sheets (in mass%, C: 0.21%, Si: 0.12%, Mn: 1.21%, P: 0.02%, S: 0.012%, Ti: 0.02%, B: 0.03%, Al: 0.04%, and the balance Fe and impurities) having the thicknesses shown in Table 1 were subjected to Al plating by the Sensen strip nitriding/dipping method. The annealing temperature was set to about 800 ℃, and the Al plating bath contained 9% of Si and also Fe eluted from the cold-rolled steel sheet. The Al basis weight after plating was adjusted by the gas wiping method, and after setting the Al basis weight per surface shown in table 1, cooling was performed. Then, a chemical solution (nanotek slurry manufactured by kasei corporation, zinc oxide particle size 70nm) was applied to the formed Al plating layer by a roll coater, and the resultant was sintered at about 80 ℃. Thus, a test material of the plated steel sheet was obtained.
< examples 1 to 4 and comparative examples 5 to 6>
Both surfaces of cold rolled steel sheets (in mass%, C: 0.21%, Si: 0.12%, Mn: 1.21%, P: 0.02%, S: 0.012%, Ti: 0.02%, B: 0.03%, Al: 0.04%, and the balance Fe and impurities) having the thicknesses shown in Table 1 were subjected to Al plating by the Sensen strip nitriding/dipping method. The annealing temperature was set to about 800 ℃, and the Al plating bath contained 9% of Si and also Fe eluted from the cold-rolled steel sheet. The Al basis weight after plating was adjusted by the gas wiping method to be set to the Al basis weight per surface shown in table 1, and then cooled. Then, a chemical solution (nanotek slurry manufactured by kasei corporation, particle size of zinc oxide particles 70nm) was applied to the formed Al plating layer by a roll coater, and the resultant was sintered at about 80 ℃. Then, zinc dioctoate (Zn — OCTOATE 22% solvent-free product, manufactured by DIC) as a zinc-based metal soap was applied onto the ZnO film by a roll coater to form a zinc-based metal soap film having an amount of deposition shown in table 1. Thus, a test material of the plated steel sheet was obtained.
< examples 5 to 8 and comparative examples 7 to 8>
Both surfaces of cold rolled steel sheets (in mass%, C: 0.21%, Si: 0.12%, Mn: 1.21%, P: 0.02%, S: 0.012%, Ti: 0.02%, B: 0.03%, Al: 0.04%, and the balance Fe and impurities) having the thicknesses shown in Table 1 were subjected to Al plating by the Sensen strip nitriding/dipping method. The annealing temperature was set to about 800 ℃, and the Al plating bath contained 9% of Si and also Fe eluted from the cold-rolled steel sheet. The Al basis weight after plating was adjusted by the gas wiping method to be set to the Al basis weight per surface shown in table 1, and then cooled. Then, zinc dioctoate (Zn-OCTOATE 22% solvent-free product, manufactured by DIC) as a zinc-based metal soap was applied to the Al plating layer formed by the roll coater to form a zinc-based metal soap film having an amount of adhesion shown in table 1. Thus, a test material of the plated steel sheet was obtained.
< evaluation >
The properties of the test materials of the plated steel sheets produced as described above were evaluated by the following methods. The average temperature increase rate when heating to 920 ℃ was set to 7.5 ℃/sec.
(1) Thermal lubricity
The thermal lubricity of the test materials of the plated steel sheets was evaluated using the thermal lubricity evaluation apparatus shown in fig. 4. The thermal lubricity evaluation device shown in fig. 4 includes a near-infrared heating furnace 100 and a mold composed of an upper mold 102A and a lower mold 102B. The upper die 102A and the lower die 102B have projections with a width of 10mm extending in a direction orthogonal to the drawing direction of the plated steel sheet, and the test material is sandwiched between the top surfaces of the projections, thereby applying a predetermined pressing load. The thermal lubricity evaluation device is further provided with a plated steel sheet heated in the near-infrared heating furnace 100 and a thermocouple (not shown) for measuring the temperature of the plated steel sheet when the plated steel sheet is clamped by the die. In fig. 4, reference numeral 10 denotes a sample of a plated steel sheet.
Using the thermal lubricity evaluation apparatus shown in fig. 4, a 30mm × 500mm test piece was heated to 920 ℃ in a nitrogen atmosphere in a near infrared heating furnace 100, and then the test piece having reached about 700 ℃ was pulled while applying a pressing load of 3kN (i.e., while sliding the test piece in a mold) through a mold composed of an upper mold 102A and a lower mold 102B, and the pulling load was measured. The drawing length was set to 100mm, and the drawing speed was set to 40 mm/s. Then, the coefficient of thermal friction (i.e., (pull load)/(press load)) was determined.
(2) Wear of die
The die wear amount was measured by analyzing the difference in surface shape of the "die of the thermal lubricity measuring apparatus" before and after (1) the evaluation test of the thermal lubricity. Specifically, a contact-type shape measuring machine was used to measure the profile of the mold surface in the sliding portion before and after sliding, and the mold wear amount was measured. The die wear amount is set to an average value of the wear amounts of the upper die and the lower die.
(3) Surface properties of test materials
The maximum value of the skewness Rsk of the roughness curve was evaluated in positive and negative with respect to the surface properties of the test material (ZnO film thereof) after (1) evaluation test of thermal lubricity. The skewness Rsk of the roughness curve was measured by the above-described method for 2 sections in the rolling direction and the rolling direction perpendicular to the rolling direction of the material. The maximum value of the values therein is used as the evaluation value. In the table, the "+" mark indicates "0 < Rsk", and the "-" mark indicates "Rsk < 0".
(4) Amount of ZnO film deposited on test Material
The amount of ZnO film deposited on the surface of the test material (in terms of Zn amount) after the evaluation test of (1) thermal lubricity was measured by the above-described method.
Table 1 below shows details of examples 1 to 8 and comparative examples 1 to 8 in a list.
In table 1, the total amount of Zn in terms of the amount of Zn adhering to the surface indicates "the amount of adhesion of the ZnO film and the zinc-based metal soap film (in terms of the amount of Zn)".
Figure GDA0002104658450000221
Confirmed by table 1: in examples 1 to 8, by forming an appropriate amount of zinc-based metal soap coating, a ZnO coating having high smoothness was formed from the zinc-based metal soap coating, and it was possible to improve the thermal lubricity and reduce the wear of the sliding surface of the mold.
In addition, it was confirmed that: in examples 1 to 8, after the evaluation test of the thermal lubricity, the peeling of the ZnO film on the surface of the test material was not observed, and the chemical conversion treatability and the corrosion resistance of the obtained molded article were improved.
In examples 2, 3, 6 and 7, the amount of zinc-based metal soap coating added to the amount of ZnO coating was more than 8.8g/m in terms of Zn amount2(excluding 8.8) and 16.3g/m2In the following case, the die wear is suppressed, and the thermal friction coefficient becomes 0.4 or less. The results confirmed that: the formability of the material in hot press forming (hot pressing) can be improved.
< examples 9 to 16, comparative example 9, and reference example 1>
During the period from the production of the plated steel sheet to the hot press forming (hot pressing) (see fig. 3), the objects (timing) and conditions (formation method, deposition amount, presence/absence of heating step for forming the zinc-based metal soap film into a ZnO film, and formation site) for forming the zinc-based metal soap film were changed as shown in table 2, and press-formed articles (dish-shaped formed articles) were produced. However, when the object of forming the zinc-based metal soap film is the surface of the Al plating layer, the ZnO film is not formed.
In hot press forming (hot pressing), the plated steel sheet was heated to 900 ℃ in the same manner as in the evaluation test of thermal lubricity, and then pressed under a pressing load of 700 ℃ and 3 kN.
The type of steel sheet, the conditions for forming the Al plating layer, the conditions for forming the ZnO coating, and the type of zinc-based metal soap were set to the same conditions as in example 1.
Then, the following evaluation was performed.
1) A test piece of plated steel sheet was prepared under the same conditions as those of the obtained molded article, and the above-described evaluation of thermal lubricity was performed using this test piece.
2) The wear amount of the die (the "fixing portion and shoulder portion of the retained steel plate" in the upper die, and the "fixing portion and shoulder portion of the retained steel plate" in the lower die) was measured in the same manner as in the evaluation of the die wear amount.
3) The surface properties of the molded article (vertical wall portion and flange portion) were evaluated in the same manner as the evaluation of the surface properties of the test material.
Table 2 below lists details of examples 9 to 16, comparative example 9, and reference example 1.
In table 2, regarding the column of the amount of adhesion of the zinc-based aliphatic metal soap coating (in terms of Zn amount), example 9 in which the zinc-based aliphatic metal soap coating was formed on the surface of the Al plating layer shows "the amount of adhesion of the zinc-based aliphatic metal soap coating itself (in terms of Zn amount)", and examples 10 to 16 in which the zinc-based aliphatic metal soap coating was formed on the surface of the ZnO coating show "the amount of adhesion of the total of the ZnO coating and the zinc-based aliphatic metal soap coating (in terms of Zn amount)".
Figure GDA0002104658450000241
Confirmed by table 2: as shown in examples 9 to 16, by forming a zinc-based metal soap coating on the surface of the Al plating layer or ZnO coating during the period from the production of the plated steel sheet to before the pressing in the hot press forming (hot pressing), it is possible to improve the hot lubricity and reduce the wear of the sliding surface of the die.
And (3) confirmation: as shown in examples 9 to 10, even when the zinc-based metal soap film was heated to form a ZnO film, the hot lubricity was improved and the wear of the sliding surface of the mold was reduced.
And (3) confirmation: as shown in examples 14 to 16, by forming at least a zinc-based metal soap film on the surface of the plated steel sheet (Al plating layer or ZnO film of plated steel sheet main body) to be the vertical wall portion and the flange portion of the molded article, wear of the sliding surface of the mold can be reduced.
And confirming that: in examples 9 to 16, peeling of the ZnO film on the surface of the molded article was not observed, and the chemical conversion treatability and corrosion resistance of the obtained molded article were improved.
In addition, it was confirmed that: as shown in comparative example 9, even when a zinc-based metal soap coating was formed on the surface of the die (the "shoulder portions and fixed portions of the upper and lower dies" on which the plated steel sheet slid during pressing), no improvement in thermal lubricity and no reduction in wear of the sliding surface of the die were observed.
However, as shown in reference example 1, by continuously supplying the metal soap so as not to cause film breakage, improvement in thermal lubricity and reduction in wear of the sliding surface of the die were seen.
While preferred embodiments of the present application have been described in detail with reference to the accompanying drawings, it is needless to say that the present application is not limited to the examples described above. Therefore, the following steps are carried out: it is obvious that a person having ordinary knowledge in the technical field to which the present application belongs can conceive various modifications and alterations within the scope of the technical idea described in the claims, and they naturally also belong to the technical scope of the present application.
It is to be noted that the disclosure of Japanese patent application No. 2016-.
All documents, patent applications, and technical specifications described in the present specification are incorporated by reference into the present specification to the same extent as if each document, patent application, and technical specification was specifically and individually described.

Claims (13)

1. A plated steel sheet for hot pressing, comprising:
a plated steel sheet body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet; and
a zinc-based metal soap film provided on the surface of the plated steel sheet body on the side of the aluminum plating layer, wherein the amount of adhesion of the adhesion portion is 7.1 to 19.8g/m in terms of Zn amount2。
2. A plated steel sheet for hot pressing, comprising:
a plated steel sheet body having a steel sheet, an aluminum plating layer provided on one or both surfaces of the steel sheet, and a zinc oxide film provided on a surface of the aluminum plating layer; and
a zinc-based metal soap film provided on the surface of the zinc oxide film of the plated steel sheet body,
the amount of the zinc oxide film and the zinc-based metal soap film adhering to the total adhering portion is calculated by the amount of Zn7.1～19.8g/m2。
3. The plated steel sheet for hot pressing according to claim 2, wherein at least half of the adhesion amount of the adhesion portion of the zinc oxide film and the zinc-based metal soap film in total is the adhesion amount of the adhesion portion of the zinc-based metal soap film.
4. The plated steel sheet for hot pressing according to any one of claims 1 to 3, wherein the zinc-based metal soap coating film is a coating film of at least one zinc-based metal soap selected from the group consisting of zinc dioctoate, zinc octoate, zinc laurate and zinc stearate.
5. A method for manufacturing a plated steel sheet for hot pressing, comprising the steps of: the surface of a plated steel sheet body having a steel sheet and an aluminum plating layer provided on one or both surfaces of the steel sheet on the aluminum plating layer side is 7.1 to 19.8g/m in terms of Zn amount in terms of the amount of deposit of a deposit portion2The zinc-based metal soap film is formed.
6. A method for manufacturing a plated steel sheet for hot pressing, comprising the steps of: on the surface of the zinc oxide film of a plated steel sheet body having a steel sheet, an aluminum plating layer provided on one or both surfaces of the steel sheet, and a zinc oxide film provided on the aluminum plating layer, the amount of adhesion of the adhesion portion in terms of Zn amount, which is the sum of the amount of adhesion of the zinc oxide film and the amount of adhesion of the adhesion portion, is 7.1 to 19.8g/m2The zinc-based metal soap film is formed.
7. The method of manufacturing a plated steel sheet for hot pressing according to claim 6, wherein in the step of forming the zinc-based metal soap film, at least half of an adhesion amount of an adhesion portion of the total of the zinc oxide film and the zinc-based metal soap film is set as an adhesion amount of an adhesion portion of the zinc-based metal soap film.
8. The method for producing a plated steel sheet for hot pressing according to any one of claims 5 to 7, which comprises a step of heating the zinc-based metal soap film at 300 ℃ or higher to form a zinc oxide film.
9. The method for producing a plated steel sheet for hot pressing according to claim 8, wherein a maximum value of a skewness Rsk of a roughness curve of a surface of the zinc oxide film formed by heating the zinc-based metal soap film is less than 0.
10. The method for producing a plated steel sheet for hot pressing according to any one of claims 5 to 7, wherein the zinc-based metal soap coating film is a coating film of at least one zinc-based metal soap selected from the group consisting of zinc dioctoate, zinc octoate, zinc laurate and zinc stearate.
11. A method for manufacturing a hot press molded article, comprising the steps of:
a step of producing a plated steel sheet for hot pressing by the method for producing a plated steel sheet for hot pressing according to any one of claims 5 to 10, wherein the step of forming the zinc-based metal soap coating film forms at least the zinc-based metal soap coating film on a surface of the plated steel sheet body on the side of the aluminum plating layer, the surface being in contact with a sliding surface of a hot-pressing die in a subsequent hot-pressing step, thereby producing the plated steel sheet for hot pressing; and
and a hot-pressing step of hot-press forming the plated steel sheet for hot-pressing.
12. A method for producing a hot press-formed product by hot press forming the plated steel sheet for hot press produced by the method for producing a plated steel sheet for hot press according to claim 9.
13. A method for manufacturing a vehicle, comprising attaching a press-molded article manufactured by the method for manufacturing a hot press-molded article according to claim 11 or claim 12 to a surface having a zinc oxide film, the surface facing the outside of the vehicle.
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