CN115053009A - Hot-pressed member, method for producing same, and plated steel sheet for hot pressing - Google Patents
Hot-pressed member, method for producing same, and plated steel sheet for hot pressing Download PDFInfo
- Publication number
- CN115053009A CN115053009A CN202080095524.7A CN202080095524A CN115053009A CN 115053009 A CN115053009 A CN 115053009A CN 202080095524 A CN202080095524 A CN 202080095524A CN 115053009 A CN115053009 A CN 115053009A
- Authority
- CN
- China
- Prior art keywords
- steel sheet
- hot
- plating layer
- alloy plating
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0242—Flattening; Dressing; Flexing
-
- 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
- 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
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
-
- 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
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C18/00—Alloys based on zinc
- C22C18/04—Alloys based on zinc with aluminium 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- 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
- C23C2/261—After-treatment in a gas atmosphere, e.g. inert or reducing atmosphere
-
- 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
- C23C2/34—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
- 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
- C23C28/322—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only
- C23C28/3225—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer only coatings of metal elements only with at least one zinc-based layer
-
- 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
- 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
-
- 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
- C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
- C23C30/005—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process on hard metal substrates
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/673—Quenching devices for die quenching
-
- 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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Inorganic Chemistry (AREA)
- Coating With Molten Metal (AREA)
- Chemical Treatment Of Metals (AREA)
- Electroplating Methods And Accessories (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
The invention provides a hot-pressed member which has excellent coating film adhesion and corrosion resistance after coating when performing electrodeposition coating after zirconium chemical conversion treatment. The hot-pressed member of the present invention is characterized by comprising a base steel sheet, and the amount of adhesion to at least one surface of the base steel sheet per one surface is 40 to 400g/m 2 The Fe-Zn-Al-Mg alloy plating layer containing alpha-Fe phase and gamma phase and the oxide layer containing Zn, Al and Mg formed on the Fe-Zn-Al-Mg alloy plating layer are formed by Co-Ka (wavelength of 25 DEG) at an incident angle of 25 DEG
) The ratio of the intensity of diffraction peak of (411) crystal face of gamma phase existing at 41.5 DEG to 2 theta to 43.0 DEG obtained by X-ray diffraction of a radiation source to the intensity of diffraction peak of (110) crystal face of alpha-Fe phase existing at 51.0 DEG to 2 theta to 52.0 DEG, I gamma/I alpha, is 0.5 or less, and the sum of Al concentration and Mg concentration of the oxide layer is 28 atom% or more.
Description
Technical Field
The present invention relates to a hot-pressed member, a method for manufacturing the same, and a plated steel sheet for hot pressing.
Background
Conventionally, chassis members, body structural members, and the like of automobiles are often manufactured by press working a steel sheet having a predetermined strength. In recent years, from the viewpoint of global environmental conservation, weight reduction of automobile bodies has been desired, and efforts have been made to increase the steel sheets used and reduce the sheet thickness thereof. However, as the strength of steel sheets increases, the press workability thereof decreases, and therefore, it is often difficult to machine the steel sheets into desired shapes of parts.
In order to solve such a problem, a processing technique called hot pressing has been proposed, which is capable of processing a heated steel sheet by a die composed of a die and a punch while increasing the working speed and simultaneously achieving both of easiness in processing and high strength. Since a plating layer having a lower electrochemical corrosion potential than that of the base steel sheet remains after heating, Zn alloy-plated steel sheets are attracting attention as hot-press steel sheets having high rust resistance, and hot-pressed parts using the Zn alloy-plated steel sheets and methods for producing the same have been proposed.
Patent document 1 describes that the Al concentration { Al } in the plating layer is 0.2 to 1.0g/m 2 And a hot-pressed member obtained by heating and hot-pressing the hot-pressed plated steel sheet in which the relationship between the concentration { Mg } (mass%) in the plating layer and the Al concentration is 0.10. ltoreq. Mg }/{ Al }. ltoreq.5
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 2006-265706
Disclosure of Invention
Patent document 1 describes that the hot-pressed member described in patent document 1 has excellent post-coating corrosion resistance when subjected to zinc phosphate-based chemical conversion treatment and then subjected to electrodeposition coating. Here, in recent years, zirconium-based chemical conversion treatment has begun to be widespread in place of conventional zinc phosphate-based chemical conversion treatment. Therefore, hot-pressed parts are also required to have coating adhesion when electrodeposition coating is performed after zirconium-based chemical conversion treatment and post-coating corrosion resistance. However, as a result of studies by the present inventors, it has been found that the hot-pressed member disclosed in patent document 1 is excellent in post-coating corrosion resistance when subjected to electrodeposition coating after zinc phosphate-based chemical conversion treatment, but is insufficient in coating adhesion and post-coating corrosion resistance when subjected to electrodeposition coating after zirconium-based chemical conversion treatment.
In view of the above problems, an object of the present invention is to provide a hot-pressed member excellent in coating adhesion when electrodeposition coating is performed after zirconium-based chemical conversion treatment and corrosion resistance after coating, and a preferable production method thereof.
Another object of the present invention is to provide a plated steel sheet for hot pressing suitable as a material for obtaining such a hot-pressed member.
The present inventors have conducted intensive studies to solve the above problems and have obtained the following findings.
In the Fe-Zn-Al-Mg alloy plating layer of a hot-pressed member, precipitation of a gamma phase composed of an intermetallic compound having a low electrochemical corrosion potential such as Fe3Zn10 is restricted, and the sum of the Al concentration and the Mg concentration is increased in a Zn-Al-Mg-containing oxide layer formed on the plating layer, whereby the coating adhesion at the time of electrodeposition coating after zirconium-based chemical conversion treatment and the corrosion resistance after coating can be improved.
In order to produce a hot-pressed member having an Fe-Zn-Al-Mg-based alloy plating layer with a small precipitation amount of the Γ phase and an oxide layer having a large total of Al concentration and Mg concentration as described above, it is necessary to heat a plated steel sheet for hot pressing having a Zn-Al-Mg-based alloy plating layer having a predetermined Al amount and Mg amount and a liquidus temperature of 400 ℃ or lower to a relatively low temperature and then hot press the steel sheet.
The gist of the present invention completed based on the above-described findings is as follows.
[1] A hot-pressed member characterized by comprising a base steel sheet, a Fe-Zn-Al-Mg alloy plating layer and an oxide layer,
the amount of the Fe-Zn-Al-Mg alloy coating layer to be coated per one surface is 40 to 400g/m 2 Formed on at least one surface of the base steel sheet and containing an alpha-Fe phase and a gamma phase,
the oxide layer is formed on the Fe-Zn-Al-Mg alloy plating layer and contains Zn, Al and Mg,
from Co-K alpha (wavelength) at an angle of incidence of 25 deg
) Intensity I of diffraction peak of (411) crystal face of gamma-phase existing at 41.5 DEG-2 theta-43.0 DEG obtained by X-ray diffraction of ray source Γ Intensity I of diffraction peak of (110) crystal face with alpha-Fe phase existing at 51.0 DEG 2 theta 52.0 DEG α Ratio of (A to (B)) Γ /I α The content of the acid-resistant acrylic resin is less than 0.5,
the sum of the Al concentration and the Mg concentration of the oxide layer is 28 atomic% or more.
[2]A method for manufacturing a hot-pressed member, characterized by heating a hot-pressed plated steel sheet to Ac 3 After the temperature range of the phase transition point to 1000 ℃, hot pressing is carried out,
the hot-pressing plated steel sheet comprises a base steel sheet and a Zn-Al-Mg alloy plating layer,
the Zn-Al-Mg alloy plating layer has an adhesion amount per one surface of 30 to 180g/m 2 A base steel sheet formed on at least one surface of the base steel sheet, and having a composition containing, in mass%, Al: 3-10% and Mg: 0.2 to 0.8%, and the balance of Zn and inevitable impurities, and has a liquidus temperature of 400 ℃ or lower in an atmospheric atmosphere.
[3] The method of producing a hot-pressed member according to item [2], wherein the Zn-Al-Mg-based alloy plating layer further contains at least one selected from the group consisting of Ca, Sr, Mn, V, Cr, Mo, Ti, Ni, Co, Sb, Zr and B in a composition of 1% by mass or less in total.
[4] A plated steel sheet for hot pressing, characterized by comprising a base steel sheet and a Zn-Al-Mg alloy plating layer,
the Zn-Al-Mg alloy plating layer has an adhesion amount per one surface of 30 to 180g/m 2 A base steel sheet formed on at least one surface of the base steel sheet, and having a composition containing, in mass%, Al: 3-10% and Mg: 0.2 to 0.8%, and the balance of Zn and inevitable impurities, and has a liquidus temperature of 400 ℃ or lower in an atmospheric atmosphere.
[5] The plated steel sheet for hot pressing according to item [4], wherein the Zn-Al-Mg-based alloy plating layer further contains at least one selected from the group consisting of Ca, Sr, Mn, V, Cr, Mo, Ti, Ni, Co, Sb, Zr and B in a composition of 1% by mass or less in total.
The hot-pressed member of the present invention has excellent coating adhesion when subjected to electrodeposition coating after zirconium-based chemical conversion treatment and excellent corrosion resistance after coating. Further, according to the method for producing a hot-pressed member of the present invention, a hot-pressed member excellent in coating adhesion when electrodeposition coating is performed after zirconium-based chemical conversion treatment and corrosion resistance after coating can be produced.
The plated steel sheet for hot pressing of the present invention is suitable as a material for producing a hot-pressed member excellent in coating adhesion when electrodeposition coating is performed after zirconium-based chemical conversion treatment and corrosion resistance after coating.
Drawings
FIG. 1 is a SEM image of a cross section of a Fe-Zn-Al-Mg alloy plating layer of No.2 hot-pressed member represented by an invention example.
FIG. 2 is a SEM image of a cross-section of the Fe-Zn-Al-Mg alloy plating layer of No.8 hot-pressed member represented by a comparative example.
Detailed Description
(Hot pressing parts)
A hot-pressed member according to one embodiment of the present invention includes a base steel sheet, an Fe-Zn-Al-Mg alloy plating layer formed on at least one surface of the base steel sheet, and an oxide layer formed on the Fe-Zn-Al-Mg alloy plating layer.
[ base Steel sheet ]
The base steel sheet in the hot-pressed member of the present embodiment is not particularly limited, and a steel sheet having a composition described in one item of a plated steel sheet for hot pressing described later is preferably used so that the tensile strength TS of the hot-pressed member is 1470MPa or more.
[ Fe-Zn-Al-Mg-based alloy plating layer ]
The Fe-Zn-Al-Mg alloy plating layer in the hot-pressed member of the present embodiment contains an α -Fe phase and a Γ phase, and preferably consists of an α -Fe phase and a Γ phase.
The α -Fe phase is a solid solution phase mainly composed of Fe and containing Zn, Al, and Mg. When a plated steel sheet for hot pressing having a Zn — Al — Mg alloy plating layer is hot-pressed, Zn, Al, and Mg in the plating layer diffuse into the base steel sheet, and a solid solution phase (α -Fe phase) containing Zn, Al, and Mg mainly containing Fe is formed in the diffusion region. It can be explained that the α -Fe phase is formed in such a manner as to attack the surface layer portion of the base steel sheet in the plated steel sheet, but generally constitutes a part of the Fe-Zn-Al-Mg system alloy plating layer located on the base steel sheet in the hot-pressed part.
The Γ phase is a phase composed of an intermetallic compound mainly composed of Zn and containing Al, Mg, and Fe, and is mainly composed of an Fe3Zn10 phase. Since the Γ phase has a crystal structure similar to that of the Γ phase and is difficult to distinguish by X-ray diffraction, the term "Γ phase" in the present specification also includes the Γ 1 phase. As intermetallic compounds having another composition constituting the Γ phase, Fe4Zn9, FeZn4, Fe5Zn21, and the like can be exemplified. During hot pressing, Fe diffused from the base steel sheet is introduced into the Zn-Al-Mg-based alloy plating layer remaining without contributing to diffusion into the base steel sheet, thereby forming a gamma phase composed of an intermetallic compound and constituting a part of the Fe-Zn-Al-Mg-based alloy plating layer in the hot-pressed member.
Here, the α -Fe phase and the Γ phase can be identified separately because they have significantly different contrasts in the cross-sectional SEM images of the Fe — Zn — Al — Mg system alloy plating layer of the hot-pressed component. Referring to fig. 1 and 2, a bright portion appears as a Γ phase and a dark portion appears as an α -Fe phase in the surface layer portion of the hot-pressed member. In addition, the alpha-Fe phase and the gamma phase can pass through Co-K alpha (wavelength) at an incident angle of 25 DEG
) Determined for X-ray diffraction from the source.
The Γ phase in the Fe-Zn-Al-Mg alloy plating layer has a significantly lower potential than the α -Fe phase of the base steel sheet, and therefore preferentially corrodes when exposed to a corrosive environment. That is, the Γ phase exhibits sacrificial corrosion protection capability to the base steel sheet, the α -Fe phase.
Here, the zinc phosphate-based chemical conversion coating film has an excellent function as a corrosion inhibitor for Zn-based alloys. Therefore, even if a hot-pressed member obtained by hot-pressing a Zn — Al — Mg alloy-plated steel sheet is subjected to zinc phosphate-based chemical conversion treatment and then subjected to electrodeposition coating, and the resulting member is in a sacrificial corrosion-resistant state due to defects that reach the base steel sheet through the coating film, the chemical conversion coating film, and the plating layer, the corrosion rate of the Γ phase is small, the corrosion rate under the coating film is sufficiently small, and the post-coating corrosion resistance is not problematic in an actual use environment.
On the other hand, the zirconium oxide-based chemical conversion coating does not have a corrosion inhibition function on the Zn-based alloy. Therefore, the corrosion rate of the Γ phase becomes high after the sacrificial anticorrosion state is achieved, and as a result, the corrosion rate under the coating film becomes high. Further, when the amount of the Γ phase is large and the Γ phase is present continuously in the Fe — Zn — Al — Mg based alloy plating layer without being broken, corrosion of the Γ phase in the under-coating environment propagates in the plane when the sacrificial anti-corrosion state is reached, and it is visually recognized as an appearance defect such as film swell. Therefore, when applying zirconium-based chemical conversion treatment, it is important to limit the amount of the Γ phase in order to ensure corrosion resistance after coating.
Therefore, in the present embodiment, as one of the requirements for improving the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating, it is important to limit the precipitation of the Γ phase composed of an intermetallic compound having a low electrochemical corrosion potential, such as Fe3Zn 10. Specifically, it is important to determine the angle of incidence of the incident light by Co-K α (wavelength) of 25 °
) Intensity I of diffraction peak of (411) crystal face of gamma-phase existing at 41.5 DEG-2 theta-43.0 DEG obtained by X-ray diffraction of ray source Γ Intensity I of diffraction peak of (110) crystal face with alpha-Fe phase existing at 51.0 DEG 2 theta 52.0 DEG α Ratio of (I) to (II) Γ /I α Is 0.5 or less. I is Γ /I α If the amount exceeds 0.5, the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating is insufficient. If I Γ /I α When the content is 0.5 or less, the gamma phase is sufficiently separated by the alpha-Fe phase in the Fe-Zn-Al-Mg based alloy plating layer, and excellent corrosion resistance after coating can be obtained when the hot-pressed member is subjected to the zirconium based chemical conversion treatment and then subjected to the electrodeposition coating.
I Γ /I α The lower limit is not particularly limited since the smaller the value of (A) is, the better, and the lower limit is, as described above, the I detected in the measurement by X-ray diffraction Γ /I α The value of (A) is usually 0.01 or more.
The ratio I is not affected by the incident angle and the measurement conditions of X-ray diffraction other than the radiation source Γ /I α The conditions described in the examples below can be adopted.
Amount of adhesion per one side: 40 to 400g/m 2
The amount of Fe-Zn-Al-Mg alloy coating of the hot-pressed member is 40 to 400g/m 2 A hot-pressed member having excellent corrosion resistance can be obtained. The adhering amount is less than 40g/m 2 In this case, a hot-pressed part having desired corrosion resistance cannot be obtained. The adhesion amount exceeds 400g/m 2 In this case, the number of cracks crossing the coating layer is significantly increased by the influence of solidification shrinkage of the coating layer after hot pressing, and the adhesion in the coating layer is significantly deteriorated. The amount of plating deposited on the hot-pressed member is preferably 50g/m 2 More preferably 60g/m or more 2 The above. Further, the amount of plating deposited on the hot-pressed member is preferably 350g/m 2 Hereinafter, more preferably 300g/m 2 The following.
In the present specification, the "amount of deposition on each surface of the Fe-Zn-Al-Mg alloy plating layer" of the hot-pressed member is determined by the following method. The hot-pressed member to be evaluated was punched out to collect 3 specimens each having a diameter of 48 mm. Then, the non-evaluation surface on the side opposite to the one surface for evaluating the adhesion amount was masked in each sample. First, each sample was immersed in a 20% chromium (VI) oxide aqueous solution at room temperature for 10 minutes to dissolve the oxide layer, and each sample was measured. Next, each sample was immersed for 120 minutes in a 500mL solution of 35% hydrochloric acid in water to a constant volume of 1L to which 3.5g of hexamethylenetetramine was added, thereby dissolving the Fe-Zn-Al-Mg-based alloy plating layer, and each sample was measured again. The amount of deposit per unit area in each sample was calculated from the difference in mass between the Fe-Zn-Al-Mg alloy plating layer before and after dissolution. Then, the average of the 3 samples was defined as the amount of adhesion per one surface.
[ oxide layer ]
The oxide layer in the hot-pressed member of the present embodiment is formed on the Fe — Zn — Al — Mg alloy plating layer, and contains Zn, Al, and Mg. When a hot-press coated steel sheet having a Zn-Al-Mg alloy plating layer is hot-pressed, Zn, Al, and Mg in the plating layer are bonded to oxygen present in a heating atmosphere to form an oxide layer containing Zn, Al, and Mg. The oxide layer is mainly composed of Al oxide, contains Zn and Mg contained in the plating layer, and may further contain elements constituting the base steel sheet, for example, Fe, Mn, Cr, and the like.
In the present embodiment, as another requirement for improving the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating, it is important that the sum of the Al concentration and the Mg concentration of the oxide layer is 28 atomic% or more. In the case where the sum of the Al concentration and the Mg concentration of the oxide layer is less than 28 atomic%, even if I is as described above Γ /I α A zirconium-based chemical conversion treatment of the hot-pressed member of 0.5 or less results in insufficient corrosion resistance after coating when electrodeposition coating is performed. This is presumably because, when the Zn concentration constituting the oxide layer is high, the reaction between the chemical conversion treatment solution and the oxide layer becomes uneven, and the unevenness in the thickness of the zirconium-based chemical conversion coating film formed on the surface of the oxide layer becomes large. That is, it is estimated that the oxide layer and the chemical conversion coating or the chemical conversion coating and the coating film are less closely adhered to each other or the coating of the chemical conversion coating is incomplete because a thin portion of the chemical conversion coating is easily formed. On the other hand, if the sum of the Al concentration and the Mg concentration of the oxide layer is 28 atomic% or more, a sound zirconium-based chemical conversion coating film is formed, and therefore, excellent post-coating corrosion resistance can be obtained when electrodeposition coating is performed after zirconium-based chemical conversion treatment is performed on the hot-pressed member.
When the sum of the Al concentration and the Mg concentration of the oxide layer is less than 28 atomic%, the oxide layer becomes brittle, and therefore, the coating film adhesion when electrodeposition coating is performed after the zirconium-based chemical conversion treatment is performed on the hot-pressed member becomes insufficient. On the other hand, if the sum of the Al concentration and the Mg concentration of the oxide layer is 28 atomic% or more, the oxide layer has sufficient strength, and therefore, the coating film adhesion when electrodeposition coating is performed after the zirconium-based chemical conversion treatment is performed on the hot-pressed member is good.
The upper limit of the sum of the Al concentration and the Mg concentration of the oxide layer is not particularly limited. However, an oxide layer containing Al and Mg at an excessively high concentration may be chemically stable in an acidic environment such as a chemical conversion treatment solution for coating a base treatment, and may inhibit formation of a chemical conversion coating film. Therefore, the sum of the Al concentration and the Mg concentration of the oxide layer is preferably 50 atomic% or less.
In the present embodiment, since the oxide layer is formed extremely thinly on the Fe — Zn — Al — Mg based alloy plating layer, it may not be visually recognized in the cross-sectional SEM image as shown in fig. 1. However, the oxide layer can be identified as a region where oxygen is detected by measuring a cross section of a surface layer portion of the hot-pressed member by energy dispersive X-ray analysis (EDX) combined with SEM and performing elemental mapping. In the present specification, "Al concentration and Mg concentration of the oxide layer" are values measured by the following methods. That is, the test piece for cross-sectional observation was taken from the flat portion of the hot-pressed member. The cross section of the Fe — Zn — Al — Mg alloy plating layer and the oxide layer containing the test piece was observed at 10000 times using a Scanning Electron Microscope (SEM) having an acceleration voltage of 15kV, and the composition of the oxide layer was measured by energy dispersive X-ray analysis (EDX) at any 3 points. The added average of the Al concentration and the Mg concentration at 3 is taken as "Al concentration of oxide layer" and "Mg concentration of oxide layer", respectively.
(method of manufacturing Hot-pressed Member)
A method for manufacturing a hot-pressed member according to an embodiment of the present invention is characterized by heating a plated steel sheet for hot pressing according to an embodiment of the present invention described later to Ac 3 After the temperature range of the phase transformation point to 1000 ℃, hot pressing is carried out.
The heating temperature of the hot-pressing steel sheet before hot-pressing is Ac 3 The Fe-Zn-Al-Mg alloy plating layer having the above-described alpha-Fe phase and gamma phase and the oxide layer having a predetermined Al concentration and Mg concentration can be obtained at a transformation point of 1000 ℃. Heating at a temperature below Ac 3 At the transformation point, after hot pressing, I of the Fe-Zn-Al-Mg system alloy coating Γ /I α May exceed 0.5. As a result, the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating is insufficient. When the heating temperature exceeds 1000 ℃, a desired oxide layer cannot be obtained, and the coating adhesion and the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating are insufficient. The term "heating temperature" as used herein refers to the maximum temperature of the steel sheet. It should be noted thatIn the present specification, "Ac 3 The transformation point "is a value calculated by the following formula based on the composition of the steel sheet.
Ac 3 Phase Change Point (. degree. C.) 910-203C 1/2 +44.7Si－4Mn+11Cr
The right element symbol of the formula represents the content of each element, and when Cr is not contained, Cr is 0.
The holding time after the temperature is raised to the heating temperature is not limited at all, and is preferably 30 seconds or more from the viewpoint of eliminating the Γ phase and avoiding liquid metal embrittlement cracking at the time of hot pressing. From the viewpoint of avoiding hydrogen intrusion due to water vapor introduced into the furnace during the holding time, the holding time is preferably within 5 minutes, more preferably within 3 minutes, and still more preferably within 2 minutes.
The method for heating the hot-pressing steel sheet is not limited at all, and examples thereof include furnace heating by an electric furnace or a gas furnace, electric heating, induction heating, high-frequency heating, flame heating, and the like.
In hot pressing, the plated steel sheet for hot pressing heated as described above is subjected to press forming and quenching simultaneously using a mold for molding to obtain a hot-pressed part having a predetermined shape. The conditions for hot pressing are not particularly limited, and a conventional method can be employed.
(plated steel sheet for hot pressing)
A coated steel sheet for hot pressing according to one embodiment of the present invention is characterized by comprising a base steel sheet and a Zn-Al-Mg alloy coating layer, wherein the Zn-Al-Mg alloy coating layer has a coating amount of 30 to 180g/m per one surface 2 A base steel sheet formed on at least one surface of the base steel sheet, and having a composition containing, in mass%, Al: 3-10% and Mg: 0.2 to 0.8%, and the balance of Zn and inevitable impurities, and has a liquidus temperature of 400 ℃ or lower in an atmospheric atmosphere.
[ base Steel sheet ]
In order to obtain a hot-pressed part having a tensile strength TS of 1470MPa or more, for example, a steel sheet having a composition containing C in mass% is preferably used as a base steel sheet: 0.20 to 0.35%, Si: 0.1-0.5%, Mn: 1.0 to 3.0%, P: 0.1% or less, S: 0.05% or less, Al: 0.1% or less, N: 0.01% or less, and the balance of Fe and inevitable impurities. The base steel sheet may be either a cold-rolled steel sheet or a hot-rolled steel sheet. The reasons for limiting the constituent elements will be described below.
C：0.20～0.35％
C increases strength by forming martensite or the like as a steel structure. In order to obtain a TS of 1470MPa or more, the C content must be 0.20% or more. On the other hand, if the C content exceeds 0.35%, the toughness of the spot welded portion deteriorates. Therefore, the amount of C is preferably 0.20 to 0.35%.
Si：0.1～0.5％
Si is an element effective for strengthening steel to obtain a good material. Therefore, the Si content needs to be 0.1% or more. On the other hand, if the Si content exceeds 0.5%, the ferrite is stabilized, and thus the hardenability is lowered. Therefore, the amount of Si is preferably 0.1 to 0.5%.
Mn：1.0～3.0％
Mn is an element effective for increasing the strength of steel. In order to ensure mechanical properties and strength, the Mn content needs to be 1.0% or more. On the other hand, if the Mn content exceeds 3.0%, surface enrichment during annealing increases, making it difficult to ensure plating adhesion. Therefore, the Mn content is preferably 1.0 to 3.0%.
P: less than 0.1%
If the amount of P exceeds 0.1%, P segregates to austenite grain boundaries during casting to cause grain boundary embrittlement, and the local deterioration of ductility lowers the balance between strength and ductility. Therefore, the P amount is preferably 0.1% or less. In addition, the amount of P is preferably 0.01% or more from the viewpoint of steel-making cost.
S: less than 0.05%
S becomes inclusions such as MnS, which causes deterioration of impact resistance and cracking of the metal flow along the welded portion. Therefore, the S content is preferably as small as possible, and is preferably 0.05% or less. In order to ensure good stretch flangeability, the S content is more preferably 0.01% or less. In addition, the S content is preferably 0.002% or more from the viewpoint of steel-making cost.
Al: less than 0.1%
If the Al content exceeds 0.1%, the punching workability and hardenability of the base steel sheet are reduced. Therefore, the amount of Al is preferably 0.1% or less. In addition, the amount of Al is preferably 0.01% or more from the viewpoint of ensuring the effect as a deoxidizing material.
N: less than 0.01%
If the N content exceeds 0.01%, AlN is formed during hot rolling or heating before hot pressing, and the blank workability and hardenability of the base steel sheet are lowered. Therefore, the amount of N is preferably 0.01% or less. In addition, the amount of N is preferably 0.001% or more from the viewpoint of steel-making cost.
The balance of the elements other than the above elements is Fe and inevitable impurities. However, for the following reasons, it is possible to appropriately contain Nb selected from the group consisting of: 0.05% or less, Ti: 0.05% or less, B: 0.0002 to 0.005%, Cr: 0.1 to 0.3%, Sb: 0.003-0.03% of at least 1 kind.
Nb: less than 0.05%
Nb is a component effective for strengthening steel, but if it is contained in excess, the shape freezing property may be reduced. Therefore, when Nb is contained, the Nb content is 0.05% or less.
Ti: less than 0.05%
Ti is also effective for strengthening steel as Nb, but if it is contained excessively, the shape freezing property may be lowered. Therefore, when Ti is contained, the Ti content is 0.05% or less.
B：0.0002～0.005％
B has an effect of inhibiting the generation and growth of ferrite from austenite grain boundaries. Therefore, the amount of B is preferably 0.0002% or more. On the other hand, addition of an excessive amount of B greatly impairs moldability. Therefore, when B is contained, the amount of B is 0.005% or less.
Cr：0.1～0.3％
Cr is useful for enhancing the strengthening and hardenability of steel. In order to exhibit such an effect, the amount of Cr is preferably 0.1% or more. On the other hand, in view of the alloy cost, when Cr is contained, the amount of Cr is 0.3% or less.
Sb：0.003～0.03％
Sb has an effect of suppressing decarburization of the surface layer of the steel sheet during hot pressing. In order to exhibit such an effect, the amount of Sb is preferably 0.003% or more. On the other hand, if the Sb amount exceeds 0.03%, the rolling load increases, and therefore the productivity decreases. Therefore, when Sb is contained, the Sb amount is 0.03% or less.
[ Zn-Al-Mg based alloy plating layer ]
In the present embodiment, the Zn — Al — Mg alloy plating layer of the hot-pressed coated steel sheet has the following composition: contains, in mass%, Al: 3-10% and Mg: 0.2 to 0.8%, the balance being Zn and unavoidable impurities, and the liquidus temperature in the atmospheric atmosphere being 400 ℃ or lower.
Al：3～10％
I of Fe-Zn-Al-Mg alloy plating layer after hot pressing when Al content is less than 3% Γ /I α May exceed 0.5 and, in addition, the sum of the Al concentration and the Mg concentration of the oxide layer may be less than 28 atomic%. As a result, the coating film adhesion and the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating are insufficient. When the Al content is less than 3%, the liquidus temperature described below cannot be set to 400 ℃ or lower by the Mg content. On the other hand, when the Al content exceeds 10%, the liquidus temperature described later cannot be set to 400 ℃ or lower, and after hot pressing, I in the Fe-Zn-Al-Mg alloy plating layer Γ /I α May exceed 0.5. As a result, the corrosion resistance after coating is insufficient when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating. Therefore, the Al content is 3 to 10%.
Mg：0.2～0.8％
Under the condition that the Mg content is less than 0.2 percent, after hot pressing, the I of the Fe-Zn-Al-Mg alloy plating layer Γ /I α May exceed 0.5. As a result, the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating is insufficient. Therefore, the Mg content is 0.2% or more, preferably 0.3% or more, and more preferably 0.4% or more. On the other hand, when the Mg content exceeds 0.8%, the sum of the Al concentration and the Mg concentration of the oxide layer after hot pressing may beLess than 28 atomic%. As a result, the coating film adhesion and the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating are insufficient. Therefore, the Mg content is 0.8% or less, preferably 0.7% or less, and more preferably 0.6% or less.
Liquidus temperature under atmospheric atmosphere: below 400 deg.C
In the present embodiment, it is important to control the Al content and the Mg content appropriately so that the liquidus temperature of the Zn — Al — Mg alloy plating layer in the atmospheric atmosphere is 400 ℃ or lower. I of Fe-Zn-Al-Mg system alloy coating after hot pressing under the condition that the liquidus temperature exceeds 400 DEG C Γ /I α May exceed 0.5. As a result, the post-coating corrosion resistance when the hot-pressed member is subjected to the zirconium-based chemical conversion treatment and then subjected to the electrodeposition coating is insufficient. The lower limit of the liquidus temperature is not particularly limited, and the liquidus temperature is about 380 ℃ or higher in the ranges of the Al content and the Mg content. The liquidus temperature of the Zn — Al — Mg alloy layer in the atmospheric atmosphere can be calculated by using the thermodynamic calculation software Thermo Calc using a database.
The inevitable impurities contained in the Zn — Al — Mg alloy plating layer include components of the base steel sheet introduced into the plating layer by the reaction between the plating bath and the base steel sheet during the plating treatment, and inevitable impurities in the plating bath. The base steel sheet to be introduced into the coating layer contains about 0.01% to several% of Fe. Examples of the type of the inevitable impurities in the plating bath include Fe, Cr, Cu, Mo, Ni, Zr, and the like. With respect to Fe in the plating layer, Fe introduced from the base steel sheet cannot be quantitatively distinguished from Fe introduced from the plating bath. The total content of the unavoidable impurities is not particularly limited, and the total content of the unavoidable impurities other than Fe is preferably 1 mass% or less from the viewpoint of uniformly melting the plating layer in the hot-pressing step.
The composition of the Zn — Al — Mg alloy plating layer may further contain, in mass%, at least one selected from Ca, Sr, Mn, V, Cr, Mo, Ti, Ni, Co, Sb, Zr, and B in the range of 1% or less in total.
Amount of adhesion per surface: 30 to 180g/m 2
The amount of Zn-Al-Mg alloy coating is set to 30 to 180g/m 2 A hot-pressed part excellent in corrosion resistance and resistance to embrittlement cracking of liquid metal at the time of hot pressing can be obtained. The adhering amount is less than 30g/m 2 In this case, a hot-pressed part having desired corrosion resistance cannot be obtained. If the amount of adhesion exceeds 180g/m 2 In the heating step before hot pressing, alloying is not completed and a liquid phase remains, and liquid metal embrittlement cracking may occur. The amount of Zn-Al-Mg-based alloy plating is preferably 45g/m 2 Above, more preferably 55g/m 2 The above. Further, the amount of Zn-Al-Mg-based alloy plating is preferably 120g/m 2 Hereinafter, more preferably 100g/m 2 The following.
In the present specification, the "amount of Zn — Al — Mg alloy plating deposited on one surface" is determined by the following method. A Zn-Al-Mg alloy-plated steel sheet to be evaluated was punched out, 3 specimens of 48mm phi were collected, and each specimen was measured. Then, the non-evaluation surface on the opposite side of the one surface for evaluating the adhesion amount was masked in each sample. Then, each sample was immersed for 10 minutes in 500mL of a 35% hydrochloric acid aqueous solution to a constant volume of 1L, to which 3.5g of hexamethylenetetramine was added, to dissolve the Zn-Al-Mg-based alloy plating layer, and each sample was measured again. The amount of deposit per unit area in each sample was calculated from the mass difference between the Zn-Al-Mg alloy plating layer before and after dissolution. Then, the average of the 3 samples was defined as the amount of adhesion per one surface.
In the present embodiment, a separate coating may be provided on the lower layer or the upper layer of the Zn — Al — Mg alloy plating layer depending on the purpose, within a range not affecting the operation and effect of the present invention. The lower layer coating film may be a nickel pre-plating film. Examples of the upper layer coating include a chemical conversion coating containing zirconium oxide and zirconium-titanium oxide.
Examples
A cold-rolled steel sheet (Ac) having a thickness of 1.4mm and having a composition of 3 814 ℃ C.) as a base steel sheet, the composition of the components being in mass%The composition comprises C: 0.23%, Si: 0.25%, Mn: 1.2%, P: 0.005%, S: 0.001%, Al: 0.03%, N: 0.004%, Nb: 0.02%, Ti: 0.02%, B: 0.002%, Cr: 0.2% and Sb: 0.008% and the balance of Fe and inevitable impurities.
The cold-rolled steel sheet was immersed in a Zn — Al — Mg hot-dip plating bath having a predetermined composition and bath temperature by a hot-dip plating facility, and then nitrogen gas was wiped off to produce hot-press plated steel sheets having levels No.1 to 14 shown in table 1. Table 1 shows the Al content, Mg content, and content of other elements in the Zn — Al — Mg based alloy plating layer and the liquidus temperature in the atmospheric atmosphere. The content and liquidus temperature of each element are controlled by adjusting the composition of the plating bath. The content of each element in the plating layer was determined by a method of quantitatively analyzing each component contained in the hydrochloric acid stripping solution for plating layer by ICP-AES. The liquidus temperature of the plating layer is determined by the above-described method. Further, Table 1 also shows the amount of deposition on each surface of the Zn-Al-Mg based alloy plating layer obtained by the above-described method. The amount of the deposited plating layer is controlled by adjusting the flow rate and linear velocity of the wiping gas.
Next, the steel sheet for hot pressing is subjected to hot pressing. That is, a test piece of 150mm × 300mm was collected from the obtained steel sheet for hot pressing, and heat-treated in an electric furnace. The heat treatment conditions (heating temperature and holding time) are shown in table 1. The heat-treated test piece was taken out of the electric furnace, and immediately hot-pressed at a molding start temperature of 700 ℃ using a cap mold, thereby obtaining a hot-pressed member. The shape of the hot-pressed member obtained was 100mm in the flat portion length of the upper surface, 50mm in the flat portion length of the side surface, and 50mm in the flat portion length of the lower surface. The mold has a radius of curvature R of 7R on both shoulders of the upper surface and both shoulders of the lower surface.
(evaluation of Fe-Zn-Al-Mg-based alloy plating layer/oxide layer of Hot-pressed parts)
A test piece for cross-sectional observation was taken from the flat portion of the upper surface of the obtained hot-pressed member, and the cross-section of the Fe-Zn-Al-Mg alloy plating layer was SEM observed. In each level, αthe-Fe and Γ phases have significantly different contrasts in cross-sectional SEM images and can therefore be identified separately. A SEM image of a cross section of the Fe-Zn-Al-Mg system alloy plating layer of the hot-pressed part of No.2 is shown in FIG. 1 as a representative of an inventive example, and a SEM image of a cross section of the Fe-Zn-Al-Mg system alloy plating layer of the hot-pressed part of No.8 is shown in FIG. 2 as a representative of a comparative example. In FIG. 1, precipitation of the Γ phase is suppressed, and the Γ phase is discontinuously dispersed in the α -Fe phase. On the other hand, in fig. 2, the Γ phase is precipitated in a large amount and exists in a continuous planar form. In addition, Co-K alpha (wavelength) at an incident angle of 25 DEG is used
) The intensity I of the diffraction peak of the (411) crystal face of the gamma-phase existing at 41.5 DEG-2 theta-43.0 DEG is measured for the X-ray diffraction of the radiation source Γ And the intensity I of the diffraction peak of the (110) crystal plane of the alpha-Fe phase existing at 51.0 DEG-2 theta-52.0 DEG α And the ratio I is Γ /I α Shown in table 1. The X-ray diffraction was measured using a bending IPX-ray diffraction apparatus (RINT-RAPID II-R, manufactured by Rigaku corporation) under the conditions of a tube voltage of 45kV, a tube current of 160mA, an integration time of 600 seconds, and a collimator diameter of 3 mm.
In addition, the Al concentration and Mg concentration of the oxide layer were measured by the above-described methods at each level, and are shown in table 1. In addition, the amount of deposition on one surface of the Fe-Zn-Al-Mg alloy plating layer was measured by the above-mentioned method at each level, and is shown in Table 1.
(evaluation 1: coating film adhesion)
A test piece of 70 mm. times.150 mm was cut out from the flat portion of the upper surface of the obtained hot-pressed member, and this test piece was subjected to zirconium-based chemical conversion treatment. Specifically, a commercially available chemical conversion treatment liquid (zirconium chemical conversion treatment: Palmyna (パルミナ)2100, manufactured by Nihon Parkerizing corporation) was used, and the bath temperature: 35 ℃ and treatment time: the chemical conversion treatment was performed for 120 seconds. Then, each test piece was subjected to voltage application for 30 seconds and held at a constant voltage for 150 seconds using a commercially available cationic electrodeposition paint, and then energized under a voltage condition that the thickness of the coating film after sintering and adhesion was 15 μm, and sintering and adhesion were carried out in an electric furnace at an atmospheric temperature of 170 ℃ for 20 minutes. As the cationic electrodeposition paint, use was made of ECTRON GT-100V-1 ash made of Kansai paint.
The electrodeposition-coated test piece was cut out with a cutter into 11 cuts reaching the base steel plate at intervals of 1mm in the longitudinal and transverse directions, respectively, to make 100 checkerboards. Cellophane tape (registered trademark) was strongly pressed against the checkerboard portion, and one end of the tape was peeled off at an angle of 45 °. The number of squares of the coating film peeled from the surface of the test piece was measured, and judged according to the following criteria, and evaluated as "excellent" or "good". The evaluation results are shown in table 1.
Very good: the number of peeling squares was 0
O: the number of peeling-off lattices is 1
And (delta): the number of peeling lattices is 2 to 5
X: the number of stripping lattices is more than 5
(evaluation 2: Corrosion resistance after coating)
A test piece subjected to electrodeposition coating was prepared in the same manner as in evaluation 1, and the end 7.5mm of the evaluation surface and the non-evaluation surface (back surface) were subjected to sealing treatment with an adhesive tape. Then, a cross-cut mark having a length of 60mm and a center angle of 60 ° was applied to the center of the evaluation surface by a cutter until reaching the depth of the base steel sheet. The test piece was subjected to a corrosion test (VDA 233-.
The maximum expansion width on one side from the cross-cut was measured, and judged according to the following criteria, and evaluated as "excellent" or "good". The evaluation results are shown in table 1.
Very good: the maximum expansion width of one side is less than 1.5mm
O: the maximum expansion width of the single side is less than or equal to 1.5mm and less than 3.0mm
And (delta): 3.0mm or less and the maximum expansion width of one side is less than 4.0mm
X: maximum expansion width of single side not greater than 4.0mm
[ Table 1]
From the results in table 1, it is understood that the hot-pressed member of the example of the present invention is excellent in the coating adhesion when the electrodeposition coating is performed after the zirconium-based chemical conversion treatment and the corrosion resistance after the coating.
Industrial applicability
The hot-pressed part of the present invention is suitable for use in chassis parts and body structure parts of automobiles.
Claims (5)
1. A hot-pressed member having a base steel sheet, a Fe-Zn-Al-Mg alloy plating layer and an oxide layer,
the amount of the Fe-Zn-Al-Mg alloy coating layer attached to each surface is 40 to 400g/m 2 Formed on at least one side of the base steel sheet and including an alpha-Fe phase and a gamma phase,
the oxide layer is formed on the Fe-Zn-Al-Mg alloy plating layer and contains Zn, Al and Mg,
intensity I of diffraction peak of (411) crystal face of gamma-phase existing at 41.5 DEG-2 theta-43.0 DEG obtained by X-ray diffraction using Co-K alpha with incidence angle of 25 DEG as radiation source Γ Intensity I of diffraction peak of (110) crystal face with alpha-Fe phase existing at 51.0 DEG 2 theta 52.0 DEG α Ratio of (A to (B)) Γ /I α Is 0.5 or less, wherein the Co-K alpha has a wavelength of
The sum of the Al concentration and the Mg concentration of the oxide layer is 28 atomic% or more.
2. A method for manufacturing a hot-pressed part, characterized by heating the plated steel sheet for hot pressing to Ac 3 Hot pressing is carried out after the temperature range of the phase transition point to 1000 ℃,
the hot-pressing plated steel sheet comprises a base steel sheet and a Zn-Al-Mg alloy plating layer,
the Zn-Al-Mg alloy plating layer has an adhesion amount per one surface of 30 to 180g/m 2 A base steel sheet formed on at least one surface of the base steel sheet, and having a composition containing Al: 3-10% and Mg: 0.2E &0.8%, and the balance of Zn and inevitable impurities, and has a liquidus temperature of 400 ℃ or lower in an atmospheric atmosphere.
3. The method of producing a hot-pressed part according to claim 2, wherein the Zn — Al — Mg alloy plating layer further contains at least one selected from Ca, Sr, Mn, V, Cr, Mo, Ti, Ni, Co, Sb, Zr, and B in a composition of 1% by mass or less in total.
4. A plated steel sheet for hot pressing, characterized by comprising a base steel sheet and a Zn-Al-Mg alloy plating layer,
the Zn-Al-Mg alloy plating layer has an adhesion amount per one surface of 30 to 180g/m 2 A base steel sheet formed on at least one surface of the base steel sheet, and having a composition containing Al: 3-10% and Mg: 0.2 to 0.8%, and the balance of Zn and inevitable impurities, and has a liquidus temperature of 400 ℃ or lower in an atmospheric atmosphere.
5. The plated steel sheet for hot pressing according to claim 4, wherein the Zn-Al-Mg-based alloy plating layer further contains at least one selected from the group consisting of Ca, Sr, Mn, V, Cr, Mo, Ti, Ni, Co, Sb, Zr, and B in a composition of 1% by mass or less in total.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020-036054 | 2020-03-03 | ||
| JP2020036054 | 2020-03-03 | ||
| PCT/JP2020/040696 WO2021176768A1 (en) | 2020-03-03 | 2020-10-29 | Hot-pressed member, method for manufacturing same, and plated steel sheet for hot pressing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115053009A true CN115053009A (en) | 2022-09-13 |
| CN115053009B CN115053009B (en) | 2024-05-31 |
Family
ID=77613213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080095524.7A Active CN115053009B (en) | 2020-03-03 | 2020-10-29 | Hot-pressed member, method for producing same, and plated steel sheet for hot pressing |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US20230095166A1 (en) |
| EP (1) | EP4116457B1 (en) |
| JP (1) | JP7056799B2 (en) |
| KR (1) | KR102666358B1 (en) |
| CN (1) | CN115053009B (en) |
| MX (1) | MX2022010448A (en) |
| WO (1) | WO2021176768A1 (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001348678A (en) * | 2000-04-03 | 2001-12-18 | Nisshin Steel Co Ltd | Precoated steel sheet excellent in durability |
| JP2005113233A (en) * | 2003-10-09 | 2005-04-28 | Nippon Steel Corp | Zn-plated steel for hot pressing |
| JP2006265706A (en) * | 2005-03-25 | 2006-10-05 | Kobe Steel Ltd | Hot dip galvanized steel sheet for heat treatment working having excellent phosphate treatability and post-painting corrosion resistance and method for manufacturing the same |
| WO2014122900A1 (en) * | 2013-02-08 | 2014-08-14 | Ｊｆｅスチール株式会社 | Surface treatment liquid for galvanized steel sheet, galvanized steel sheet with surface treatment film and method for producing same |
| CN104136650A (en) * | 2012-03-07 | 2014-11-05 | 杰富意钢铁株式会社 | Steel sheet for hot pressing, manufacturing process therefor, and process for producing hot-pressed member using same |
| KR20150073021A (en) * | 2013-12-20 | 2015-06-30 | 주식회사 포스코 | Alloy plated steel sheet for hot press forming having excellent anti-corrosion and method for manufacturing the same |
| CN104755655A (en) * | 2012-10-31 | 2015-07-01 | 杰富意钢铁株式会社 | Hot-pressing steel plate, hot-pressing member and manufacturing method for the hot-pressing member |
| CN108350555A (en) * | 2015-10-26 | 2018-07-31 | Posco公司 | The galvanized alloy steel plate and its manufacturing method of excellent in bending workability |
| CN108430662A (en) * | 2015-12-22 | 2018-08-21 | Posco公司 | The hot-forming product and its manufacturing method of corrosion resistance excellent |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012112010A (en) * | 2010-11-26 | 2012-06-14 | Jfe Steel Corp | Plated steel sheet for hot press, method for manufacturing hot-pressed member using the same, and hot-pressed member |
| TR201903572T4 (en) * | 2011-02-28 | 2019-04-22 | Nisshin Steel Co Ltd | Steel plate hot dip coated with Zn-Al-Mg based system, and the process of its production. |
| JP5341270B1 (en) * | 2012-04-25 | 2013-11-13 | 日新製鋼株式会社 | Method for producing black-plated steel sheet and method for producing molded body of black-plated steel sheet |
| CA2914464C (en) * | 2013-06-11 | 2017-07-18 | Nippon Steel & Sumitomo Metal Corporation | Hot stamp molded body, and method for producing hot stamp molded body |
| US20210180172A1 (en) * | 2016-08-08 | 2021-06-17 | John Speer | Modified hot-dip galvanize coatings with low liquidus temperature, methods of making and using the same |
-
2020
- 2020-10-29 WO PCT/JP2020/040696 patent/WO2021176768A1/en active Application Filing
- 2020-10-29 MX MX2022010448A patent/MX2022010448A/en unknown
- 2020-10-29 JP JP2021510138A patent/JP7056799B2/en active Active
- 2020-10-29 KR KR1020227023141A patent/KR102666358B1/en active Active
- 2020-10-29 EP EP20923408.7A patent/EP4116457B1/en active Active
- 2020-10-29 CN CN202080095524.7A patent/CN115053009B/en active Active
- 2020-10-29 US US17/905,277 patent/US20230095166A1/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001348678A (en) * | 2000-04-03 | 2001-12-18 | Nisshin Steel Co Ltd | Precoated steel sheet excellent in durability |
| JP2005113233A (en) * | 2003-10-09 | 2005-04-28 | Nippon Steel Corp | Zn-plated steel for hot pressing |
| JP2006265706A (en) * | 2005-03-25 | 2006-10-05 | Kobe Steel Ltd | Hot dip galvanized steel sheet for heat treatment working having excellent phosphate treatability and post-painting corrosion resistance and method for manufacturing the same |
| CN104136650A (en) * | 2012-03-07 | 2014-11-05 | 杰富意钢铁株式会社 | Steel sheet for hot pressing, manufacturing process therefor, and process for producing hot-pressed member using same |
| CN104755655A (en) * | 2012-10-31 | 2015-07-01 | 杰富意钢铁株式会社 | Hot-pressing steel plate, hot-pressing member and manufacturing method for the hot-pressing member |
| WO2014122900A1 (en) * | 2013-02-08 | 2014-08-14 | Ｊｆｅスチール株式会社 | Surface treatment liquid for galvanized steel sheet, galvanized steel sheet with surface treatment film and method for producing same |
| KR20150073021A (en) * | 2013-12-20 | 2015-06-30 | 주식회사 포스코 | Alloy plated steel sheet for hot press forming having excellent anti-corrosion and method for manufacturing the same |
| CN108350555A (en) * | 2015-10-26 | 2018-07-31 | Posco公司 | The galvanized alloy steel plate and its manufacturing method of excellent in bending workability |
| CN108430662A (en) * | 2015-12-22 | 2018-08-21 | Posco公司 | The hot-forming product and its manufacturing method of corrosion resistance excellent |
Also Published As
| Publication number | Publication date |
|---|---|
| EP4116457B1 (en) | 2024-05-08 |
| KR20220109459A (en) | 2022-08-04 |
| JP7056799B2 (en) | 2022-04-19 |
| CN115053009B (en) | 2024-05-31 |
| MX2022010448A (en) | 2022-09-19 |
| EP4116457A1 (en) | 2023-01-11 |
| EP4116457A4 (en) | 2023-01-11 |
| KR102666358B1 (en) | 2024-05-14 |
| JPWO2021176768A1 (en) | 2021-09-10 |
| WO2021176768A1 (en) | 2021-09-10 |
| US20230095166A1 (en) | 2023-03-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108699664B (en) | High-strength hot-dip galvanized steel sheet with excellent impact peeling resistance and corrosion resistance of processed parts | |
| KR101290030B1 (en) | Method for producing hot-pressed member | |
| KR101445813B1 (en) | HIGH-STRENGTH STEEL SHEET HAVING EXCELLENT HYDROGEN EMBRITTLEMENT RESISTANCE AND MAXIMUM TENSILE STRENGTH OF 900 MPa OR MORE, AND PROCESS FOR PRODUCTION THEREOF | |
| JP6004102B2 (en) | Hot stamp molded body and method for producing hot stamp molded body | |
| RU2635499C2 (en) | Galvanised hot dipping and alloyed steel sheet and method of its manufacture | |
| KR101668638B1 (en) | Hot-dip galvannealed steel sheet | |
| CN104245999B (en) | High-strength hot-dip zinc-coated steel sheet and manufacture method thereof | |
| CN102482753A (en) | High-strength hot-dip galvanized steel sheet and process for producing same | |
| JP2012132092A (en) | Method for manufacturing cold rolled steel sheet, cold rolled steel sheet and automobile member | |
| KR20110088551A (en) | Hot-dip galvanized steel sheet and its manufacturing method | |
| WO2012029631A1 (en) | Method for producing cold-rolled steel sheet, cold-rolled steel sheet, and vehicle member | |
| CN104145039B (en) | High-strength hot-dip zinc-coated steel sheet and manufacture method thereof | |
| CN112805395A (en) | Hot-rolled steel sheet and method for producing same | |
| JP6406475B1 (en) | Al-plated welded pipe for quenching, Al-plated hollow member and method for producing the same | |
| CN115667571A (en) | Hot-pressed component | |
| CN107849667A (en) | Steel plate, hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel plate and their manufacture method | |
| CN116209781B (en) | Steel Plate | |
| JP7453583B2 (en) | Al-plated hot stamping steel material | |
| WO2022091529A1 (en) | Hot-pressed member, steel sheet for hot-pressing, and methods for producing same | |
| JP5835547B2 (en) | Method for producing Si-containing cold-rolled steel sheet | |
| CN115053009B (en) | Hot-pressed member, method for producing same, and plated steel sheet for hot pressing | |
| WO2023132289A1 (en) | Steel sheet for hot stamping and hot stamp molded body | |
| CN118103543A (en) | Hot-pressed component | |
| JP5835548B2 (en) | Method for producing Si-containing cold-rolled steel sheet | |
| CN113614285A (en) | Hot stamp-molded body |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |