WO2020213688A1 - めっき鋼板 - Google Patents
めっき鋼板 Download PDFInfo
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- WO2020213688A1 WO2020213688A1 PCT/JP2020/016756 JP2020016756W WO2020213688A1 WO 2020213688 A1 WO2020213688 A1 WO 2020213688A1 JP 2020016756 W JP2020016756 W JP 2020016756W WO 2020213688 A1 WO2020213688 A1 WO 2020213688A1
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- WIPO (PCT)
- Prior art keywords
- phase
- plating layer
- mgzn
- steel sheet
- plated steel
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/012—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/043—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of metal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/18—Layered products comprising a layer of metal comprising iron or steel
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- 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
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- 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
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- 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
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
- C23C2/0222—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating in a reactive atmosphere, e.g. oxidising or reducing atmosphere
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- 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
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- C—CHEMISTRY; METALLURGY
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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
- 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
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- 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
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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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
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- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
- C23C2/285—Thermal after-treatment, e.g. treatment in oil bath for remelting the coating
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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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
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- C23C2/29—Cooling or quenching
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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
- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
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- Y10T428/1275—Next to Group VIII or IB metal-base component
- Y10T428/12757—Fe
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12951—Fe-base component
- Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]
Definitions
- the present invention relates to a plated steel sheet.
- the present application claims priority based on Japanese Patent Application No. 2019-080288 filed in Japan on April 19, 2019, the contents of which are incorporated herein by reference.
- Patent Document 1 in mass%, Al: 25 to 90% and Sn: 0.01 to 10% are contained, and more than one selected from the group consisting of Mg, Ca and Sr is 0.
- a hot-dip Al—Zn-based plated steel sheet having a plating layer containing 01 to 10% is disclosed.
- Patent Document 2 uses a molten Zn—Al—Mg alloy plated steel plate in which the ratio of [Al / Zn / Zn 2 Mg ternary eutectic structure] to the outermost surface of the plating layer is 60 area% or more as a base material. It contains at least one selected from Ni, Co, Fe, and Mn, and the total amount of Ni, Co, and Fe attached is in the range of 0.05 to 5.0 mg / m 2 , and the amount of Mn attached is 0.05 to.
- Precipitated layer in the range of 30 mg / m 2 , average particle size: phosphate film consisting of phosphate crystals of 0.5 to 5.0 ⁇ m, valve metal oxide or hydroxide and valve metal fluoride
- the surface of the plating layer is covered with a coexisting chemical conversion coating, the base of the phosphate crystal bites into the plating layer and stands up from the plating layer, and the chemical conversion coating is an exposed plating layer or precipitation between the phosphate crystals.
- a chemical conversion-treated steel plate characterized by being an organic resin film via an interfacial reaction layer formed at an interface with a layer is disclosed.
- the surface of the steel material contains Mg: 1 to 10%, Al: 2 to 19%, Si: 0.01 to 2%, and Fe: 2 to 75% in mass%.
- a zinc-based alloy-plated steel material is disclosed, wherein the balance has a zinc-based alloy-plated layer composed of Zn and unavoidable impurities.
- Patent Document 4 discloses a technique of adding Mg to an Al—Zn-based plating layer for the purpose of providing a zinc-based alloy-plated steel material having excellent corrosion resistance and weldability.
- Patent Documents 1 to 4 when the techniques disclosed in Patent Documents 1 to 4 are applied to automobile applications, Al oxide is formed on the surface of the plating layer due to Al contained in the plating layer, and as a result, chemical conversion is formed. There was a possibility that the processability was inferior. In particular, in Patent Document 4, a large amount of Fe—Zn phase, which lowers the chemical conversion processability, is formed in the plating layer.
- the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plated steel sheet having excellent chemical conversion processability.
- the present invention adopts the following configuration. That is, the plated steel sheet according to a certain viewpoint of the present invention includes a steel material and a plating layer provided on the surface of the steel material, and the plating layer is mass% and Al: 5.00 to 35.00%. It contains Mg: 2.50 to 13.00%, Fe: 5.00 to 35.00%, Si: 0 to 2.00%, and Ca: 0.03 to 2.00%, and the balance is It is composed of Zn and impurities, and on the surface of the plating layer, the area fraction of the Fe—Al phase is 0 to 30%, and the area fraction of the lamellar structure of rod-shaped Zn and MgZn 2 is 5 to 90%, which is massive. The area fraction of the MgZn 2- phase is 10 to 70%, and the area fraction of the balance is 10% or less.
- the plating layer may contain Al: 10.00 to 30.00% in mass%.
- the plating layer may contain Mg: 3.00 to 10.00% in mass%.
- the plating layer may contain 4.00% or more of Mg in mass%.
- the plating layer may contain Ca: 0.03 to 1.00% in mass%.
- the surface integral of the lamellar structure may be 10 to 60% on the surface of the plating layer.
- the area fraction of Al—Zn dendrite mainly composed of an Al phase and a Zn phase may be 5% or less.
- the surface integral of the Zn / Al / MgZn 2 ternary eutectic structure may be 5% or less on the surface of the plating layer.
- the surface integral of the massive Zn phase may be 10% or less on the surface of the plating layer.
- the surface integral of the plate-shaped Zn / MgZn 2 lamellar structure on the surface of the plating layer may be 10% or less.
- the surface integral of the Mg 2 Si phase may be 10% or less on the surface of the plating layer.
- the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
- the plated steel sheet according to the present embodiment includes a steel material and a plating layer provided on the surface of the steel material.
- the plating layer is by mass%. Al: 5.00 to 35.00%, Mg: 2.50 to 13.00%, Fe: 5.00 to 35.00%, Si: 0 to 2.00% and Ca: 0 to 2.00%, The rest consists of Zn and impurities
- the area fraction of the Fe—Al phase is 0 to 30%
- the area fraction of the lamellar structure of rod-shaped Zn and MgZn 2 is 5 to 90%
- the area fraction of the massive MgZn 2 phase The rate is 10 to 70%
- the area fraction of the balance is 10% or less.
- the lamella structure of rod-shaped Zn and MgZn 2 having excellent chemical conversion treatment property and the massive MgZn 2 phase, preferably further Fe—Al phase are positively generated in the plating layer, while By suppressing the formation of phases that reduce the chemical conversion processability, such as Al—Zn dendrite and Fe—Zn phase, the chemical conversion processability of the plated steel sheet is enhanced. Further, since the plated steel sheet according to the present embodiment contains a large amount of lamellar structure of rod-shaped Zn and MgZn 2 , liquid metal embrittlement cracking (LME) during spot welding is suitably prevented (excellent LME resistance is obtained). ) Can also be done.
- LME liquid metal embrittlement cracking
- the material of the steel material (base steel sheet) that is the base of the plated steel sheet is not particularly limited. It is possible to use general steel, Ni pre-plated steel, Al killed steel, and some high alloy steels. The shape of the steel material is also not particularly limited.
- the plated steel sheet having excellent chemical conversion processability according to the present embodiment includes a plating layer on the surface of the steel material.
- Al 5.0 to 35.00%
- Al is an element necessary for containing an element other than Zn in the plating layer.
- Zn layer Zn plating layer
- Mg Mg cannot be added at a high concentration.
- Al is contained in the plating layer (Zn-based plating layer)
- a plating layer containing Mg can be produced.
- Fe dispersed in the plating layer reacts (alloys) with Al in preference to Zn, and is an Fe—Al phase (for example, Fe 2 Al 5 ) which is advantageous in corrosion resistance and LME resistance after coating. Phase) can be formed.
- the Fe—Al phase does not necessarily have to be formed in the plating layer, but when the Fe—Al phase is formed in the plating layer, corrosion resistance and LME resistance after coating can be further improved. .. Further, addition of Mg is also effective for suppressing the formation of the Fe—Zn phase, and the effect is particularly exhibited when the Mg concentration is 2.50% or more.
- the Mg concentration is more preferably 4.00% or more.
- the Al concentration is less than 5.00%, it tends to be difficult to contain an alloying element that imparts performance to the plating layer in addition to Mg. Further, since Al has a low density, a large amount of Al phase is formed with respect to the mass-based content as compared with Zn. However, when the Al concentration is less than 5.00%, most of the plating layer tends to be in the Zn phase. As a result, the chemical conversion processability is significantly reduced. In the plating layer, it is not preferable that the Zn phase becomes the first phase from the viewpoint of chemical conversion treatment. Further, if the Al concentration is less than 5.0%, a large amount of dross is generated on the plating bath when Mg is added, which makes it impossible to manufacture a plated steel sheet. Therefore, the Al concentration is 5.0% or more, preferably 5.00% or more, and more preferably 10.00% or more.
- the Al concentration is set to 35.00% or less, preferably 30.00% or less.
- Al concentration is set to 35.00% or less, preferably 30.00% or less.
- the amount of Al existing as the Al phase is reduced, and as a result, the Al phase is mainly a factor for lowering the corrosion resistance.
- the content of dendrites composed of the Zn phase is reduced.
- Mg 2.50 to 13.00% Mg is an element necessary for imparting chemical conversion treatment property.
- Mg When Mg is added to the Zn-based plating layer, Mg forms MgZn 2 which is an intermetallic compound. Further, Mg also has a property of suppressing the formation of the Fe—Zn phase.
- the minimum Mg concentration required to sufficiently improve the chemical conversion processability of the plating layer and further suppress the formation of the Fe—Zn phase is 2.50%. Therefore, the Mg concentration is 2.50% or more, preferably 3.00% or more, and more preferably 4.00% or more.
- the Mg concentration is 13.00% or less, preferably 11.00% or less, and more preferably 10.00% or less.
- the formation of the Fe—Zn phase is suppressed by adding a predetermined amount of Al and Mg to the plating layer. Therefore, in the present embodiment, the Fe—Zn phase is substantially not present in the plating layer.
- the Fe—Zn phase not only lowers the corrosion resistance after coating, but also tends to generate red rust when the coated surface is scratched, so it is preferable not to generate it as much as possible.
- Examples of the type of Fe—Zn phase include ⁇ phase, ⁇ phase, and ⁇ phase.
- the chemical composition of the plating layer is adjusted to the composition of the present embodiment (particularly Al concentration and Mg concentration are important), and the alloying temperature is set to 440 ° C to 480 ° C. Must be.
- Fe 5.00 to 35.00% If the Fe concentration is less than 5.00%, the amount of Fe is insufficient, and the Fe—Al phase formed may decrease, which is not preferable. Further, if the Fe concentration is less than 5.00%, the area ratio of Al—Zn dendrite that does not contribute to the improvement of chemical conversion treatment property may exceed 5%, which is not preferable. Therefore, the Fe concentration is set to 5.00% or more, preferably 10.00% or more, and more preferably 15.00% or more. If the Fe concentration exceeds 35.00%, there is a high possibility that the desired metal structure is not formed in the plating layer according to the present embodiment, and the potential rises with the increase in the Fe component, which is an appropriate sacrifice for the steel material.
- the Fe concentration is set to 35.00% or less, preferably 30.00% or less, and more preferably 25.00% or less. Further, the Fe concentration is preferably such that Fe / Al is 0.9 to 1.2 with respect to the Al concentration.
- the Fe concentration is set to 35.00% or less in the above range, the Fe 2 Al 5 phase can be easily formed. If Fe / Al is less than 0.9, it becomes difficult to generate a sufficient amount of Fe 2 Al 5 phase, and as a result, dendrites composed of Al phase and Zn phase are excessively generated. Further, when Fe / Al exceeds 1.2, the Fe—Zn-based intermetallic compound phase is likely to be formed, and in this case as well, the Fe 2 Al 5 phase is difficult to be formed.
- Si 0 to 2.00% Since Si is an element effective for improving the adhesion between the steel material and the plating layer, Si may be contained in the plating layer. Since Si does not have to be contained in the plating layer, the lower limit of the Si concentration is 0%. Since the effect of improving the adhesion by Si is exhibited when the Si concentration in the plating layer is 0.03% or more, it is preferably 0.03% or more when Si is contained in the plating layer. On the other hand, even if the Si concentration in the plating layer exceeds 2.00%, the adhesion improving effect of Si is saturated. Therefore, even when Si is contained in the plating layer, the Si concentration is 2.00% or less. And. The Si concentration is preferably 1.00% or less.
- Ca 0.03 to 2.00% Since Ca is an element effective for improving the chemical conversion treatment property of the plated steel sheet, Ca is contained in the plating layer. Since the effect of improving the chemical conversion treatment property by Ca is expressed when the Ca concentration in the plating layer is 0.03% or more, the Ca concentration is 0.03% or more, preferably 0.05% or more. On the other hand, even if the Ca concentration in the plating layer exceeds 2.00%, the effect of improving the chemical conversion treatment property by Ca is saturated. Therefore, even when Ca is contained in the plating layer, the Ca concentration is 2.00%. It is as follows. The Ca concentration is preferably 1.00% or less.
- the remaining part excluding Al, Mg, Fe, Si and Ca is Zn and impurities.
- the impurity means an element that is inevitably mixed in the plating process, and these impurities may be contained in a total of about 3.00%. That is, the content of impurities in the plating layer may be 3.00% or less.
- the elements that can be contained as impurities and the concentrations of those elements are, for example, Sb: 0 to 0.50%, Pb: 0 to 0.50%, Cu: 0 to 1.00%, Sn: 0 to 1.
- Examples thereof include 00%, Ti: 0 to 1.00%, Sr: 0 to 0.50%, Ni: 0 to 1.00%, and Mn: 0 to 1.00%. If an impurity element is contained in the plating layer in excess of these concentrations, it may hinder the acquisition of desired properties, which is not preferable.
- the chemical composition of the plating layer can be measured by, for example, the following method. First, an acid solution in which the plating layer is peeled and dissolved with an acid containing an inhibitor that suppresses corrosion of the base iron (steel material) is obtained. Next, the chemical composition (type and content of chemical components) of the plating layer can be obtained by measuring the obtained acid solution by ICP analysis.
- the acid type is not particularly limited as long as it is an acid capable of dissolving the plating layer.
- the chemical composition is measured as the average chemical composition of the entire plating layer to be measured. In the examples described later, the chemical composition (chemical composition) of the plating layer was measured by this method.
- the area fraction of the Fe—Al phase is 0 to 30%, and the area fraction of the lamellar structure (Zn / MgZn 2 lamellar structure) of the rod-shaped Zn and MgZn 2 is It is 5 to 90%, the area fraction of the massive MgZn 2 phase is 10 to 70%, and the area fraction of the rest is 10% or less.
- FIG. 1 is an SEM image showing the structure of the surface of the plating layer 10 according to the present embodiment. As shown in FIG. 1, on the surface of the plating layer 10 according to the present embodiment, observation using SEM shows that the lamellar structure 11 of rod-shaped Zn and MgZn 2 and the hexagonal massive MgZn 2- phase 12 The Fe—Al phase 13 is observed.
- FIG. 2 is an SEM image showing the structure of the surface of the plating layer 100 according to the prior art.
- the plating layer 100 according to the prior art shown in FIG. 2 is formed by subjecting a steel material to hot-dip Zn—Al—Mg-based plating according to the prior art.
- Al—Zn dendrite 14 and Zn / Al / MgZn 2 ternary eutectic structure 15 occupy most of the plating layer 100.
- the massive Zn phase 16 and Mg 2 Si phase 17 are also observed.
- the massive MgZn 2 phase 18 is not hexagonal, and the lamellar structure of rod-shaped Zn and MgZn 2 , the hexagonal massive MgZn 2 phase, and the Fe—Al phase are not observed.
- the structure of the plating layer according to this embodiment will be described.
- the Fe—Al phase according to the present embodiment is a phase containing an intermetallic compound of Fe and Al, and examples of the intermetallic compound include Fe 2 Al 5 and Fe Al.
- the chemical conversion treatment property is excellent. Since the surface integral of the Fe—Al phase that does not impair the chemical conversion treatment property is 30%, the upper limit thereof is set to 30%, preferably less than 20%.
- the Fe—Al phase is an important structure not only for chemical conversion treatment but also for suitably preventing liquid metal embrittlement cracking (LME) during spot welding (obtaining excellent LME resistance).
- Rod-shaped Zn / MgZn 2 Surface integral of lamellar structure 5 to 90%
- the rod-shaped Zn / MgZn 2 lamellar structure is a rod-shaped lamellar structure composed of a Zn phase and an intermetallic compound MgZn 2 phase.
- the rod shape means that the three-dimensional shape of the MgZn 2 phase contained in the Zn / MgZn 2 lamellar structure is rod-shaped, and the Zn phase surrounds the rod-shaped MgZn 2 phase.
- This rod-shaped Zn / MgZn 2 lamellar structure is an important structure for the plating layer according to the present embodiment to exhibit suitable chemical conversion treatment properties.
- the plating layer according to the present embodiment contains Ca, and as described later, the rod-shaped Zn / MgZn 2 lamella is rapidly cooled at an average cooling rate of 20 ° C./sec or more after the alloying step. Tissue is formed.
- the surface integral ratio of the rod-shaped Zn / MgZn 2 lamellar structure is 5% or more, suitable chemical conversion treatment property can be obtained. Therefore, the surface integral of the rod-shaped Zn / MgZn 2 lamellar structure is set to 5% or more, preferably 10% or more.
- the surface integral of the rod-shaped Zn / MgZn 2 lamellar structure is set to 90% or less, preferably 70% or less, and more preferably 60% or less.
- the rod-shaped Zn / MgZn 2 lamellar structure is important not only for chemical conversion treatment but also for the plated steel sheet to obtain desired LME resistance. Although the details of the mechanism are unknown, it is considered that the reason why the rod-shaped Zn / MgZn 2 lamellar structure provides excellent LME resistance is that Ca is efficiently contained in the structure.
- the surface integral of the hexagonal massive MgZn 2 phase is preferably 10% or more, more preferably 70% or more.
- the area fraction of the hexagonal massive MgZn 2 phase is more than 70%, the area fraction of the Fe—Al phase or the rod-shaped Zn / MgZn 2 lamellar structure is too low, which is suitable for chemical conversion treatment. Since it is difficult to obtain the property, the area fraction of the massive MgZn 2- phase is set to 70% or less.
- the total area fraction of the remaining structure other than the Fe—Al phase, rod-shaped Zn / MgZn 2 lamellar structure, and massive MgZn 2 phase is 10%. It is preferably 7.5% or less, and more preferably 5% or less.
- the structure contained in the remaining portion include a plate-shaped Zn / MgZn 2 lamellar structure, Al—Zn dendrite, Zn / Al / MgZn 2 ternary eutectic structure, a massive Zn phase, and an Mg 2 Si phase, which will be described later. Each of these tissues contained in the rest will be described below.
- the plate-shaped Zn / MgZn 2 lamellar structure is a plate-shaped lamellar structure composed of a Zn phase and an intermetallic compound MgZn 2 phase.
- the rod-shaped Zn / MgZn 2 lamellar structure is a structure necessary for obtaining chemical conversion treatment, but the plate-shaped Zn / MgZn 2 lamellar structure does not contribute to the chemical conversion treatment. Therefore, from the viewpoint of obtaining suitable chemical conversion treatment property, the surface integral of the plate-shaped Zn / MgZn 2 lamellar structure is set to 10% or less, preferably 5% or less.
- the rod-shaped Zn / MgZn 2 lamellar structure and the plate-shaped Zn / MgZn 2 lamellar structure are identified by the difference in structure, and the MgZn 2 phase is identified by whether it is rod-shaped or plate-shaped.
- the rod shape means that the three-dimensional shape of the MgZn 2 phase contained in the Zn / MgZn 2 lamellar structure is rod-shaped, and the Zn phase surrounds the rod-shaped MgZn 2 phase.
- the plate shape means that the three-dimensional shape of the MgZn two- phase contained in the Zn / MgZn 2 lamellar structure is plate-like.
- the plate-shaped Zn / MgZn 2 lamellar structure a structure in which the plate-shaped Zn phase and the plate-shaped MgZn 2 phase are alternately laminated is formed.
- the three-dimensional shape of the MgZn two- phase can be investigated by observing the metal structure while scraping the metal structure in the depth direction by mechanical polishing or FIB processing.
- Al—Zn dendrite Area fraction of dendrite (Al—Zn dendrite) mainly composed of Al phase and Zn phase: 5% or less
- Al primary crystals ⁇ - (Zn, Al) phase crystallized as primary crystals
- Al—Zn dendrites After that, by heating to a temperature range of 440 ° C. to 480 ° C. and performing the alloying treatment, most of the Al—Zn dendrites are replaced with another structure, but some of them remain after the alloying treatment.
- the surface integral of Al—Zn dendrite is set to 5% or less, more preferably 3% or less.
- “mainly” means that the Al phase and the Zn phase of the dendrite are contained in an area fraction of about 15% or more, and the balance other than the Al phase and the Zn phase is 5% or less of Fe and 3%.
- the following Mg and 1% or less steel component elements (Ni, Mn) may be contained.
- Zn / Al / MgZn 2 Area fraction of ternary eutectic structure: 5% or less Zn / Al / MgZn 2 ternary eutectic structure is outside the Al primary crystal part by Zn—Al—Mg based eutectic reaction. It is a layered structure of a Zn layer, an Al layer, and an MgZn 2 layer, which is composed of a Zn phase, an Al phase, and an MgZn 2 phase finally solidified.
- the Zn / Al / MgZn 2 ternary eutectic structure also has an effect of improving the chemical conversion treatment property, but the improvement effect is inferior to that of the Fe—Al phase or the rod-shaped Zn / MgZn 2 lamellar structure. Therefore, it is preferable that the surface integral of the Zn / Al / MgZn 2 ternary eutectic structure is lower. Therefore, in the plating layer according to the present embodiment, the area fraction of Zn / Al / MgZn 2 ternary eutectic structure is 5% or less, more preferably 3% or less.
- the bulk Zn phase is a structure that may be formed when the Mg content in the plating layer is low. When the lumpy Zn phase is formed, the swelling width of the coating film tends to be large, so that the area ratio is preferably low, preferably 10% or less.
- Bulk Zn phase and Zn phase contained in the Zn / MgZn 2 binary eutectic structure is a separate phase.
- the massive Zn phase has a dendrite shape and may be observed as a circle on the cross-sectional structure.
- intermetallic compound phase 10% or less Since the other intermetallic compound phase does not have a favorable effect on the chemical conversion treatment property, the area fraction is preferably 10% or less, more preferably 5% or less.
- the term "surface integral" refers to the arithmetic of five randomly selected different samples when the area fraction of the desired structure on the surface of the plating layer is calculated, unless otherwise specified. Refers to the average value. This surface integral actually represents the volume fraction in the plating layer.
- the surface integral of each structure in the plating layer is determined by the following method. First, the plated steel sheet to be measured is cut into 25 (c) ⁇ 25 (L) mm to obtain a surface SEM image of the plating layer and an element distribution image by EDS.
- Constituent structure of the plating layer that is, Fe—Al phase, lamellar structure of rod-shaped Zn and MgZn 2 , massive MgZn 2 phase, Al—Zn dendrite, Zn / Al / MgZn 2 ternary eutectic structure, massive Zn phase, plate
- the area fraction of the Zn / MgZn 2 lamellar structure, Mg 2 Si phase, and other intermetallic compound phase is a total of 5 visual fields (1500 times magnification) from 5 different samples of the surface EDS mapping image of the plating layer. ) Is photographed, and the area fraction of each tissue is measured by image analysis.
- the regions containing Fe, Zn, Al, Mg, and Si can be displayed in different colors. Therefore, in this mapping image, the phase composed of Al and Fe is determined to be the Fe—Al phase. Further, in the mapping image, the structure composed of the rod-shaped MgZn 2 phase and the Zn phase surrounding the rod-shaped MgZn 2 phase is determined to be the rod-shaped Zn / MgZn 2 lamellar structure. Other phases can be determined in the same way.
- the area of the visual field may be, for example, 45 ⁇ m ⁇ 60 ⁇ m.
- the plated steel sheet according to the present embodiment has excellent chemical conversion treatment property by providing a steel material and a plating layer having the above-mentioned characteristics. Further, the plated steel sheet according to the present embodiment has excellent LME resistance by providing the steel material and the plating layer having the above-mentioned characteristics.
- the chemical conversion-treated film applicable to the plated steel sheet according to the present embodiment is not particularly limited, but may be, for example, a Zn-phosphate treated film in which hopite, which is a Zn-phosphate crystal, is mainly formed.
- the method for producing a plated steel sheet according to the present embodiment includes a hot-dip galvanizing step in which a base steel sheet is immersed in a plating bath containing at least Al, Mg, Ca, and Zn to perform hot-dip galvanizing, and the hot-dip galvanized base material. It has an alloying step of heating the steel sheet to 440 ° C. to 480 ° C. for 2 to 8 seconds, and a cooling step of cooling the steel sheet to 335 ° C. at an average cooling rate of 20 ° C./sec or more.
- hot-dip galvanizing is performed by immersing the base steel sheet in a plating bath containing at least Al, Mg, Ca, and Zn.
- a plating bath is attached to the surface of the base steel sheet, and then the base steel sheet is pulled up from the plating bath to solidify the molten metal adhering to the surface of the base steel sheet by a so-called hot-dip galvanizing method.
- the composition of the plating bath may contain at least Al, Mg, Ca, and Zn, and the raw material may be mixed and dissolved so as to have the composition of the plating layer described above.
- the temperature of the plating bath is preferably in the range of more than 380 ° C. and 600 ° C. or lower, and may be in the range of 400 to 600 ° C.
- the surface of the base steel sheet by heating the base steel sheet in a reducing atmosphere before immersing it in the plating bath.
- heat treatment is performed at 600 ° C. or higher, preferably 750 ° C. or higher for 30 seconds or longer in a mixed atmosphere of nitrogen and hydrogen.
- the base steel sheet after the reduction treatment is cooled to the temperature of the plating bath and then immersed in the plating bath.
- the immersion time may be, for example, 1 second or more.
- the amount of plating adhered is adjusted by gas wiping.
- the amount of adhesion is preferably in the range of 10 to 300 g / m 2 per one side of the base steel sheet, and may be in the range of 20 to 250 g / m 2 .
- the method for producing a plated steel sheet according to the present embodiment includes an alloying step in which the hot-dip galvanized base steel sheet is heated in a temperature range of 440 ° C. to 480 ° C. for 2 to 8 seconds after the hot-dip galvanizing step.
- the alloying step a plating layer having a desired structure (that is, a structure having a surface integral as described above) is formed, and excellent chemical conversion treatment property can be obtained.
- the alloying temperature In the alloying step, if the heating temperature (hereinafter referred to as alloying temperature) is less than 440 ° C., the alloying progress is slow, which is not preferable. Therefore, the alloying temperature is set to 440 ° C. or higher. On the other hand, if the alloying temperature exceeds 480 ° C., the alloying process proceeds excessively in a short time, and the alloying process cannot be suitably controlled, which is not preferable. For example, in the alloying step, Fe dispersed in the plating layer reacts with Al in preference to Zn to form an Fe—Al phase, but if the alloying proceeds excessively, the surplus that does not react with Al Fe reacts with Zn in the plating layer to form a large amount of Fe—Zn phase. Therefore, the alloying temperature is set to 480 ° C. or lower.
- the alloying time is set to 2 seconds or more.
- the alloying time exceeds 8 seconds, the alloying proceeds remarkably, which is not preferable. For example, a large amount of Fe—Zn phase is produced as in the case where the alloying temperature is too high. Therefore, the alloying time is set to 8 seconds or less.
- the heating means is not particularly limited, and examples thereof include heating means such as induction heating.
- the temperature range from the alloying temperature to 335 ° C (hereinafter referred to as a cooling temperature range) is cooled at an average cooling rate of 20 ° C./sec or more. Has a cooling step.
- the average cooling rate in the cooling temperature range is set to 20 ° C./sec or more, preferably 25 ° C./sec or more.
- the plated steel sheet according to the present embodiment can be manufactured.
- the plated steel sheet according to this embodiment has excellent chemical conversion treatment properties. Further, the plated steel sheet according to the present embodiment has excellent LME resistance.
- Example 1 ⁇ Base steel plate>
- a cold-rolled steel sheet (0.2% C-1.5% Si-2.6% Mn) having a thickness of 1.6 mm was used.
- Test No. 1 was formed so that the plating layer of the chemical components shown in Table 1 was formed on the base steel sheet. Plating baths with different chemical components were constructed for each (level). The chemical composition of the plating layer was measured by the method described above.
- the plated steel sheet was subjected to an alloying step under the conditions of the alloying temperature and alloying time shown in Table 1. In the alloying step, an induction heating device was used.
- the prepared sample was cut into 25 (c) ⁇ 25 (L) mm to obtain a surface SEM image of the plating layer and an element distribution image by EDS.
- Constituent structure of the plating layer that is, Fe—Al phase, lamellar structure of rod-shaped Zn and MgZn 2 , massive MgZn 2 phase, Al—Zn dendrite, Zn / Al / MgZn 2 ternary eutectic structure, massive Zn phase, plate Jo of Zn / MgZn 2 lamellar structure, Fe-Zn phase, Mg 2 Si phase, total area fraction of other intermetallic phases, from five different sample surface EDS mapping image of the plating layer, in each one field of view 5
- the visual field (magnification 1500 times) was photographed, and the area fraction of each tissue was measured by image analysis.
- the area of each visual field was 45 ⁇ m ⁇ 60 ⁇ m.
- the specific measurement method is as described above.
- the Fe—Zn phase was recorded as another intermetallic compound phase), and the performance was inferior.
- the cooling rate was too slow (Comparative Example 16)
- the Zn / MgZn 2- rod-shaped lamellar structure was not formed, and the remaining structure was excessively formed, resulting in inferior performance.
- Example 2 In Example 2, the LME resistance of some of the examples used in Example 1 was examined. That is, the components, structure, and manufacturing conditions of the plated steel sheet used in Example 2 are shown in Table 1.
- ⁇ LME resistance> The plated steel sheets according to some of the examples used in Example 1 were cut into a size of 200 ⁇ 20 mm, subjected to a hot V-bending test, and subjected to hot V-bending at 800 ° C. The presence or absence of LME cracks was investigated by observing the cross section of the processed portion after the V-bending process, and the LME resistance was evaluated. In a V-bending die with an angle of 90 °, "AAA” means that LME cracking does not occur even if R is 6 mm, “AA” means that LME cracking does not occur even if R is 8 mm, and LME cracking occurs when R is 16 mm. Was not generated as "A”. The passing level was A or higher.
- the evaluation results of LME resistance of each example are shown in Table 3. Since the surface integral ratio of each tissue is shown in Table 2, it is not shown in Table 3.
- LME resistance was suitable in each example. Above all, in the example in which the rod-shaped Zn / MgZn 2 lamellar structure was present in an amount of 30% or more, the LME resistance tended to be “AA”. Further, in the example in which the Fe—Al phase was present in an amount of 20% or more, the LME resistance was “AAA”. When the LME resistance was evaluated in the same manner in the comparative examples, the LME resistance was B or less in all the comparative examples.
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Abstract
Description
本願は、2019年4月19日付で日本に出願された特願2019-080288号に基づき優先権を主張し、その内容をここに援用する。
すなわち、本発明のある観点によるめっき鋼板は、鋼材と、前記鋼材の表面に設けられためっき層と、を備え、前記めっき層は、質量%で、Al:5.00~35.00%、Mg:2.50~13.00%、Fe:5.00~35.00%、Si:0~2.00%、及び、Ca:0.03~2.00%、を含有し、残部がZn及び不純物からなり、前記めっき層の表面において、Fe-Al相の面積分率が0~30%、棒状のZnとMgZn2とのラメラ組織の面積分率が5~90%であり、塊状MgZn2相の面積分率が10~70%であり、残部の面積分率が10%以下である。
本実施形態に係るめっき鋼板は、鋼材と、前記鋼材の表面に設けられためっき層と、を備え、
前記めっき層は、質量%で、
Al:5.00~35.00%、
Mg:2.50~13.00%、
Fe:5.00~35.00%、
Si:0~2.00%、及び、
Ca:0~2.00%、を含有し、
残部がZn及び不純物からなり、
前記めっき層の表面において、Fe-Al相の面積分率が0~30%、棒状のZnとMgZn2とのラメラ組織の面積分率が5~90%であり、塊状MgZn2相の面積分率が10~70%であり、残部の面積分率が10%以下である。つまり、本実施形態では、化成処理性に優れた棒状のZnとMgZn2とのラメラ組織、及び塊状MgZn2相、好ましくはさらにFe-Al相をめっき層内に積極的に生成させる一方で、化成処理性を低下させる相、例えばAl-Znデンドライト及びFe-Zn相等の生成を抑制することにより、めっき鋼板の化成処理性を高める。さらに、本実施形態に係るめっき鋼板は、棒状のZnとMgZn2とのラメラ組織を多く含むので、スポット溶接時の液体金属脆化割れ(LME)を好適に防ぐ(優れた耐LME性を得る)こともできる。
めっき鋼板の下地となる鋼材(母材鋼板)の材質は、特に限定されない。一般鋼、Niプレめっき鋼、Alキルド鋼、一部の高合金鋼を用いることが可能である。鋼材の形状も特に限定されない。
本実施形態に係る化成処理性に優れるめっき鋼板は、鋼材の表面にめっき層を備える。
次に、めっき層の化学成分について説明する。なお、以下の説明において、特段の断りが無い限りは「%」は「質量%」を表すものとする。
Alは、めっき層中にZn以外の他元素を含有させるために必要な元素である。本来、Znめっき層(Zn層)には、他元素が含有しづらく、例えば、Mgを高濃度に添加できない。しかし、めっき層(Zn系めっき層)に、Alが含有されることで、Mgを含む、めっき層を製造することができる。さらには、合金化処理においてめっき層中に分散したFeがZnよりも優先してAlと反応(合金化)して塗装後耐食性及び耐LME性に有利なFe-Al相(例えばFe2Al5相)を形成することができる。さらには、合金化処理において塗装後耐食性を低下させるFe-Zn相の生成を抑制することができる。なお、Fe-Al相は必ずしもめっき層中に形成されていなくてもよいが、Fe-Al相がめっき層中に形成されている場合、塗装後耐食性及び耐LME性をさらに向上することができる。また、Fe-Zn相の生成抑制にはMg添加も有効であり、特にその効果はMg濃度を2.50%以上とすることで発現する。Mg濃度は4.00%以上であることがさらに好ましい。
また、Al濃度が5.0%未満では、Mg添加した場合にめっき浴上にドロスが大量に生成し、めっき鋼板を製造することが不可能となる。よって、Al濃度は、5.0%以上とし、好ましくは5.00%以上であり、より好ましくは10.00%以上である。
このように、本実施形態では、Al濃度及び後述するFe濃度をバランスさせる(所定の濃度範囲に調整する)ことで、Alを積極的にFeと反応させてFe-Al相としている。したがって、本実施形態では、めっき層中のAlを主としてFe-Al相として存在させることで、Al相として存在するAlの量を低減させ、その結果として、耐食性低下要因となる主にAl相とZn相から構成されるデンドライトの含有量を低減させている。
Mgは、化成処理性を付与するために必要な元素である。Zn系のめっき層中にMgが添加されると、Mgは金属間化合物であるMgZn2を形成する。さらに、MgはFe-Zn相の生成を抑制するという特性も有する。めっき層の化成処理性を十分に向上させ、さらにFe-Zn相の生成を抑制するために最低限必要なMg濃度は2.50%である。そのため、Mg濃度を2.50%以上とし、好ましくは3.00%以上であり、さらに好ましくは4.00%以上である。
一方、Mg濃度が13.00%超では、MgZn2相が急速に相量を増し、めっき層の塑性変形能が失われ、加工性が劣化するため好ましくない。よって、Mg濃度は、13.00%以下とし、好ましくは11.00%以下であり、より好ましくは10.00%以下である。
このように、本実施形態では、所定量のAl及びMgをめっき層に添加することで、Fe-Zn相の生成を抑制している。このため、本実施形態では、めっき層中にはFe-Zn相は実質的に存在しない。特に、Fe-Zn相は、塗装後耐食性を低下させるのみならず、塗装面に傷がついた場合に赤錆を発生させやすいので、極力生成しないようにすることが好ましい。なお、Fe-Zn相の種別としては、Γ相、δ相、ζ相が挙げられる。Fe-Zn相の生成を抑制するためには、めっき層の化学組成を本実施形態の組成(特にAl濃度、Mg濃度が重要である)に調整するとともに、合金化温度を440℃~480℃とする必要がある。
Fe濃度が5.00%未満では、Fe量が不十分であるため、形成されるFe-Al相が少なくなってしまう場合があるため好ましくない。また、Fe濃度が5.00%未満では、化成処理性の向上に寄与しないAl-Znデンドライトの面積率が5%超となる場合があるため、好ましくない。そのため、Fe濃度を5.00%以上とし、好ましくは10.00%以上、より好ましくは15.00%以上とする。
Fe濃度が35.00%超では、本実施形態に係るめっき層で所望の金属組織が形成されない可能性が高く、Fe成分の増加に伴う電位の上昇が起こって、鋼材に対して適切な犠牲防食能を維持できず腐食速度の増加を誘発する可能性があるため好ましくない。そのため、Fe濃度を35.00%以下とし、好ましくは30.00%以下、より好ましくは25.00%以下とする。
また、Fe濃度は、Al濃度に対し、Fe/Alが0.9~1.2となるようにすることが好ましい。Fe/Alを上記範囲とすることで、Fe2Al5相が形成されやすくなる。
Fe/Alが0.9未満であると、Fe2Al5相を十分量生成させることが困難となり、結果としてAl相とZn相から構成されるデンドライトが過剰に生成する。
また、Fe/Alが1.2超であると、Fe-Zn系金属間化合物相が形成されやすくなり、この場合もFe2Al5相が形成されにくくなる。
Siは、鋼材とめっき層との密着性を向上させるのに有効な元素であるため、Siをめっき層に含有させてもよい。Siはめっき層に含有させなくてもよいので、Si濃度の下限値は0%である。Siによる密着性向上効果はめっき層中のSi濃度が0.03%以上で発現するため、Siをめっき層に含有させる場合には0.03%以上とすることが好ましい。
一方、めっき層中のSi濃度が2.00%を超えても、Siによる密着性向上効果は飽和するため、Siをめっき層中に含有させる場合であってもSi濃度は2.00%以下とする。Si濃度は、好ましくは1.00%以下である。
Caは、めっき鋼板の化成処理性を向上させるのに有効な元素であるため、Caをめっき層に含有させるものとする。Caによる化成処理性向上効果はめっき層中のCa濃度が0.03%以上で発現するため、Ca濃度を0.03%以上とし、好ましくは0.05%以上である。
一方、めっき層中のCa濃度が2.00%を超えても、Caによる化成処理性向上効果は飽和するため、Caをめっき層中に含有させる場合であってもCa濃度は2.00%以下とする。Ca濃度は、好ましくは1.00%以下である。
Al,Mg,Fe,Si,Caを除く残部は、Zn及び不純物である。ここで、不純物とはめっきの過程で不可避的に混入する元素を意味し、これら不純物は合計で3.00%程度含まれてもよい。つまり、めっき層における不純物の含有量を3.00%以下としてもよい。
不純物として含まれ得る元素とそれらの元素の濃度としては、例えば、Sb:0~0.50%、Pb:0~0.50%、Cu:0~1.00%、Sn:0~1.00%、Ti:0~1.00%、Sr:0~0.50%、Ni:0~1.00%、及びMn:0~1.00%などが挙げられる。これらの濃度を超過して不純物元素がめっき層に含まれると、所望の特性を得ることを阻害してしまう可能性があるため好ましくない。
本実施形態に係るめっき層は、その表面において、Fe-Al相の面積分率が0~30%、棒状のZnとMgZn2とのラメラ組織(Zn/MgZn2ラメラ組織)の面積分率が5~90%であり、塊状MgZn2相の面積分率が10~70%であり、残部の面積分率が10%以下である。
図2に示すように、従来技術に係るめっき層100では、合金化処理が行われていないので、Al-Znデンドライト14やZn/Al/MgZn2三元共晶組織15が大部分を占めており、塊状Zn相16やMg2Si相17も観察される。塊状MgZn2相18は六角形形状ではなく、棒状のZnとMgZn2とのラメラ組織や、六角形形状の塊状MgZn2相や、Fe-Al相は観察されない。
以下、本実施形態に係るめっき層の組織について説明する。
本実施形態に係るめっき鋼板では、後述するように溶融めっき工程後に合金化工程を行うことで、めっき層中にFe-Al相が形成されることが好ましい。なお、本実施形態に係るFe-Al相はFeとAlとの金属間化合物を含む相であり、金属間化合物としてはFe2Al5、FeAlなどが挙げられる。
本実施形態に係るめっき層がFe-Al相はめっき層の表面組織に露出しない方が化成処理性に優れる。化成処理性を阻害しないFe-Al相の面積分率は30%であるため、その上限を30%とし、好ましくは20%未満である。
なお、Fe-Al相は、化成処理性だけでなく、スポット溶接時の液体金属脆化割れ(LME)を好適に防ぐ(優れた耐LME性を得る)ためにも重要な組織である。
棒状のZn/MgZn2ラメラ組織とは、Zn相と、金属間化合物であるMgZn2相とで構成される棒状のラメラ組織である。ここで、棒状とは、Zn/MgZn2ラメラ組織に含有されるMgZn2相の三次元的な形状が棒状であり、棒状MgZn2相の周囲をZn相が取り囲んだ組織形態を有することを意味する。この棒状のZn/MgZn2ラメラ組織は、本実施形態に係るめっき層が好適な化成処理性を発揮する上で、重要な組織である。上述したように本実施形態に係るめっき層がCaを含有し、かつ、後述するように合金化工程の後で20℃/秒以上の平均冷却速度で急冷することにより棒状のZn/MgZn2ラメラ組織が形成される。
棒状のZn/MgZn2ラメラ組織の面積分率が5%以上である場合に、好適な化成処理性を得ることができる。そのため、棒状のZn/MgZn2ラメラ組織の面積分率を5%以上とし、好ましくは10%以上である。
一方、棒状のZn/MgZn2ラメラ組織の面積分率が90%超の場合には、化成処理性の向上効果が飽和するだけでなく、めっき層表面に共晶凝固に起因した凹凸が生じ、めっき鋼板の外観が低下するため好ましくない。そのため、棒状のZn/MgZn2ラメラ組織の面積分率を90%以下とし、好ましくは70%以下とし、より好ましくは60%以下とする。
なお、棒状のZn/MgZn2ラメラ組織は、化成処理性だけでなく、めっき鋼板が所望の耐LME性を得るためにも重要な組織である。機構の詳細は不明であるが、棒状のZn/MgZn2ラメラ組織が優れた耐LME性をもたらすのは、該組織にCaが効率的に含有されることに起因すると考えられる。
好適な化成処理性を得るためには、六角形形状を有する塊状MgZn2相の面積分率を10%以上とすることが好ましく、より好ましくは70%以上である。
一方、六角形形状を有する塊状MgZn2相の面積分率が70%超であると、Fe-Al相や棒状のZn/MgZn2ラメラ組織の面積分率が低すぎてしまい、好適な化成処理性を得ることが困難となるため、塊状MgZn2相の面積分率を70%以下とする。
好適な化成処理性を得るため、Fe-Al相、棒状のZn/MgZn2ラメラ組織、塊状MgZn2相以外の残部の組織の面積分率を合計で10%以下とし、好ましくは7.5%以下、より好ましくは5%以下とする。
残部に含まれる組織としては、後述する板状のZn/MgZn2ラメラ組織、Al-Znデンドライト、Zn/Al/MgZn2三元共晶組織、塊状Zn相、Mg2Si相などが挙げられる。残部に含まれるこれらの組織について各々以下に説明する。
板状のZn/MgZn2ラメラ組織とは、Zn相と、金属間化合物であるMgZn2相とで構成される板状のラメラ組織である。上述のように、棒状のZn/MgZn2ラメラ組織は化成処理性を得るために必要な組織であるが、板状のZn/MgZn2ラメラ組織は化成処理性に寄与するものではない。そのため、好適な化成処理性を得る観点から、板状のZn/MgZn2ラメラ組織の面積分率を10%以下とし、好ましくは5%以下とする。
なお、棒状のZn/MgZn2ラメラ組織と板状のZn/MgZn2ラメラ組織とは、組織形態の差異で識別し、MgZn2相が棒状であるか板状であるかで識別する。ここで、棒状とは、上述したように、Zn/MgZn2ラメラ組織に含有されるMgZn2相の三次元的な形状が棒状であり、棒状MgZn2相の周囲をZn相が取り囲んだ組織形態を有することを意味する。板状とはZn/MgZn2ラメラ組織に含有されるMgZn2相の三次元的な形状が板状であることを表す。つまり、板状のZn/MgZn2ラメラ組織では、板状のZn相と板状のMgZn2相とが交互に積層された組織が形成されている。
なお、MgZn2相の三次元的な形状は、機械研磨やFIB加工などで奥行方向に金属組織を削りつつ、金属組織を観察することで調査することが可能である。
めっき層を形成する際に、後述する溶融めっき工程後に浴温から冷却される過程において、まずAl初晶(初晶として晶出したα-(Zn,Al)相)が晶出し、デンドライト状に成長する(以下、Al-Znデンドライトと呼称する)。その後440℃~480℃の温度範囲に加熱して合金化処理を行うことにより、ほとんどのAl-Znデンドライトは別の組織に置換されるが、一部は合金化処理後も残存する。
Al-Znデンドライトは化成処理性や耐LME性に好ましい影響を与えないため、その面積分率はより低い方が好ましい。そのため、本実施形態に係るめっき層では、Al-Znデンドライトの面積分率を5%以下とし、より好ましくは3%以下とする。
なお、「主に」とはデンドライトのうちAl相とZn相とが面積分率で約15%以上含まれることを指し、Al相とZn相以外の残部としては5%以下のFe、3%以下のMg、1%以下の鋼成分元素(Ni、Mn)が含まれ得る。
Zn/Al/MgZn2三元共晶組織とは、Zn-Al-Mg系共晶反応により、Al初晶部の外部に最終的に凝固したZn相、Al相、MgZn2相から構成される、Zn層、Al層、MgZn2層の層状の組織である。Zn/Al/MgZn2三元共晶組織にも化成処理性の向上効果はあるが、Fe-Al相や棒状のZn/MgZn2ラメラ組織に比べるとその向上効果は劣る。そのため、Zn/Al/MgZn2三元共晶組織の面積分率はより低い方が好ましい。そのため、本実施形態に係るめっき層では、Zn/Al/MgZn2三元共晶組織の面積分率を5%以下とし、より好ましくは3%以下とする。
塊状Zn相は、めっき層中のMg含有量が低い場合に形成することがある組織である。塊状Zn相が形成すると塗膜膨れ幅が大きくなる傾向にあるため、その面積率は低い方がこのましく、10%以下が好ましい。塊状Zn相は、Zn/MgZn2二元共晶組織に含有されるZn相とは別個の相である。塊状Zn相はデンドライト形状を有し、断面組織上では円状として観察されることもある。
その他の金属間化合物相も化成処理性に好ましい影響を及ぼさないので面積分率は10%以下が好ましく、より好ましくは5%以下である。その他の金属間化合物相としては、その他の金属間化合物相としては、例えばMg2SiCaZn11相、Al2CaSi2相、Al2CaZn2相などが挙げられる。
めっき層における各組織の面積分率は以下の方法によって求める。
まず、測定対象となるめっき鋼板を25(c)×25(L)mmに切断し、めっき層の表面SEM像ならびにEDSによる元素分布像を得る。めっき層の構成組織、すなわちFe-Al相、棒状のZnとMgZn2とのラメラ組織、塊状MgZn2相、Al-Znデンドライト、Zn/Al/MgZn2三元共晶組織、塊状Zn相、板状のZn/MgZn2ラメラ組織、Mg2Si相、その他の金属間化合物相の面積分率は、めっき層の表面EDSマッピング像を異なる5サンプルから、各1視野で合計5視野(倍率1500倍)を撮影し、画像解析により各組織の面積分率を測定する。例えば、EDSマッピング像では、Fe、Zn,Al、Mg、Siが含有される領域を色分け表示することができる。そこで、このマッピング像中、AlとFeから構成される相をFe-Al相と判断する。また、マッピング像中、棒状のMgZn2相と、その周囲を囲むZn相から成る組織を棒状のZn/MgZn2ラメラ組織と判断する。他の相も同様の方法で判断できる。視野の面積は例えば45μm×60μmであってもよい。各組織の面積分率は、例えば視野毎に測定された各組織の面積分率(=(いずれかの視野中の各組織の面積)/(その視野の面積)×100)の算術平均値として求められる。後述する実施例では、この方法により各組織の面積分率を測定した。
本実施形態に係るめっき鋼板は、上述の特徴を有する鋼材及びめっき層を備えることで優れた化成処理性を有する。
また、本実施形態に係るめっき鋼板は、上述の特徴を有する鋼材及びめっき層を備えることで、優れた耐LME性を有する。なお、本実施形態に係るめっき鋼板に適用可能な化成処理膜は特に制限されないが、例えばりん酸Zn結晶であるホパイトを主体に形成させるりん酸Zn処理膜であってもよい。
次に、本実施形態に係るめっき鋼板の製造方法について説明する。
本実施形態に係るめっき鋼板の製造方法は、少なくともAl,Mg,Ca,Znを含むめっき浴に母材鋼板を浸漬させて溶融めっきを施す溶融めっき工程と、前記溶融めっきを施した前記母材鋼板を440℃~480℃に2~8秒間加熱する合金化工程と、20℃/秒以上の平均冷却速度で335℃まで冷却する冷却工程と、を有する。
溶融めっき工程では、少なくともAl,Mg,Ca,Znを含むめっき浴に母材鋼板を浸漬させて溶融めっきを施す。
めっき浴の組成は、少なくともAl,Mg,Ca,Znを含んでいればよく、上述のめっき層の組成になるように原料を配合して溶解したものを用いればよい。
本実施形態に係るめっき鋼板の製造方法は、溶融めっき工程後に、溶融めっきを施した母材鋼板を440℃~480℃の温度範囲に2~8秒間加熱する合金化工程を有する。合金化工程により、所望の組織(すなわち、上述した面積分率の組織)を有するめっき層が形成され、優れた化成処理性を得ることができる。
一方、合金化温度が480℃超では、合金化が短時間で過剰に進行してしまうことにより、合金化工程を好適に制御できないため好ましくない。例えば、合金化工程では、めっき層に分散したFeはZnよりも優先してAlと反応してFe-Al相を形成するが、合金化が過剰に進行すると、Alと反応しなかった余剰のFeがめっき層中のZnと反応して大量のFe-Zn相を生成する。そのため、合金化温度を480℃以下とする。
一方、合金化時間が8秒超では、合金化が著しく進行してしまうため好ましくない。例えば、合金化温度が高すぎる場合と同様に、Fe-Zn相が大量に生成される。そのため、合金化時間を8秒以下とする。
本実施形態に係るめっき鋼板の製造方法は、合金化工程後に、20℃/秒以上の平均冷却速度で、合金化温度から335℃までの温度範囲(以下、冷却温度範囲と呼称する)を冷却する冷却工程を有する。
本実施形態に係るめっき鋼板は、優れた化成処理性を有する。また、本実施形態に係るめっき鋼板は、優れた耐LME性を有する。
<母材鋼板>
めっきを施す母材鋼板としては、板厚1.6mmの冷延鋼板(0.2%C-1.5%Si-2.6%Mn)を用いた。
表1に示す化学成分のめっき層が母材鋼板上に形成されるように、試験No.(水準)毎に異なる化学成分のめっき浴を建浴した。めっき層の化学成分は、上述した方法により測定した。
母材鋼板を100mm×200mmに切断した後、バッチ式の溶融めっき試験装置でめっきを施した。板温は母材鋼板中心部にスポット溶接した熱電対を用いて測定した。
めっき浴浸漬前、酸素濃度20ppm以下の炉内においてN2-5%H2ガス、露点0℃の雰囲気にて860℃で母材鋼板表面を加熱還元処理した。その後、N2ガスで空冷して浸漬板温度が浴温+20℃に到達した後、表1に示す浴温のめっき浴に約3秒間浸漬した。
めっき浴浸漬後、引上速度100~500mm/秒で引上げた。引き抜き時、N2ワイピングガスでめっき付着量を制御した。
ワイピングガスでめっき付着量を制御した後、表1に示す合金化温度及び合金化時間の条件により、めっき鋼板に対して合金化工程を施した。合金化工程では、誘導加熱装置を用いた。
表1に示す条件で、冷却温度範囲を冷却することにより、めっき鋼板を合金化温度から335℃まで冷却した。
めっき層の組織構成を調査するため、作製したサンプルを25(c)×25(L)mmに切断し、めっき層の表面SEM像ならびにEDSによる元素分布像を得た。めっき層の構成組織、すなわちFe-Al相、棒状のZnとMgZn2とのラメラ組織、塊状MgZn2相、Al-Znデンドライト、Zn/Al/MgZn2三元共晶組織、塊状Zn相、板状のZn/MgZn2ラメラ組織、Fe-Zn相、Mg2Si相、その他の金属間化合物相の面積分率は、めっき層の表面EDSマッピング像を異なる5サンプルから、各1視野で合計5視野(倍率1500倍)を撮影し、画像解析により各組織の面積分率を測定した。各視野の面積は45μm×60μmとした。具体的な測定方法は上述した通りである。
各実施例及び比較例での各組織の面積分率を表2に記した。
各実施例及び比較例に対して、以下の方法で化成処理性を評価した。
上述の方法で製造した各実施例及び比較例に係るめっき鋼板を50×100mmの大きさに切り出し、りん酸Zn処理(SD5350システム:日本ペイント・インダストリアルコーディング社製規格)を施した。
Znりん酸処理を施しためっき鋼板に対して、化成処理結晶の被覆率をSEM観察にて評価した。化成処理結晶の被覆率が表面の面積に対して100%の場合を「AAA」、98%以上の場合を「AA」、95%以上の場合を「A」、95未満~90%の場合を「B」、90未満~85%の場合を「C」、85%未満の場合を「D」とした。合格レベルをA以上とした。
一方、Al及びFeが不足する水準(比較例1)ではめっき鋼板に過剰にドロスが付着し、化成処理性が大きく劣化した。Mgが不足する水準(比較例2)では十分量の塊状MgZn2相を生成することができず、さらに化成処理性を低下させる残部の組織が過剰に生成されており(面積分率((A)~(F)の合計が10.0%を超えており)、性能が劣位であった。
実施例2は、実施例1で用いたいくつかの実施例に対して耐LME性を調べたものである。つまり、実施例2で用いためっき鋼板の成分、組織、製造条件は表1に記載されている。
実施例1で用いたいくつかの実施例に係るめっき鋼板を200×20mmの大きさに切り出し、熱間V曲げ試験に供し、800℃において熱間V曲げ加工を施した。V曲げ加工後の加工部を断面観察することでLME割れの有無を調査し、耐LME性を評価した。角度が90°のV曲げ金型にて、Rが6mmでもLME割れが生じなかった場合を「AAA」、Rが8mmでもLME割れを生じなかった場合を「AA」、Rが16mmでLME割れを生じなかった場合を「A」とした。合格レベルをA以上とした。
各実施例の耐LME性の評価結果を表3に示した。なお、各組織の面積分率は表2に記載しているので、表3には記載していない。
11 : 棒状のZnとMgZn2とのラメラ組織
12 : 塊状MgZn2相
13 : Fe-Al相
14 : Al-Znデンドライト
15 : 塊状Zn
16 : Fe-Al相
17 : Mg2Si相
18 : 塊状MgZn2相(六角形形状ではない)
Claims (11)
- 鋼材と;
前記鋼材の表面に設けられためっき層と;を備え、
前記めっき層は、質量%で、
Al:5.00~35.00%、
Mg:2.50~13.00%、
Fe:5.00~35.00%、
Si:0~2.00%、及び、
Ca:0.03~2.00%、を含有し、
残部がZn及び不純物からなり、
前記めっき層の表面において、Fe-Al相の面積分率が0~30%、棒状のZnとMgZn2とのラメラ組織の面積分率が5~90%であり、塊状MgZn2相の面積分率が10~70%であり、残部の面積分率が10%以下であることを特徴とする、めっき鋼板。 - 前記めっき層が、質量%で、Al:10.00~30.00%を含有することを特徴とする、請求項1に記載のめっき鋼板。
- 前記めっき層が、質量%で、Mg:3.00~10.00%を含有することを特徴とする、請求項1又は2に記載のめっき鋼板。
- 前記めっき層が、質量%で、Mgを4.00%以上含有することを特徴とする、請求項1~3の何れか1項に記載のめっき鋼板。
- 前記めっき層が、質量%で、Ca:0.03~1.00%を含有することを特徴とする、請求項1~4の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、前記ラメラ組織の面積分率が10~60%であることを特徴とする、請求項1~5の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、主にAl相とZn相とから構成されるAl-Znデンドライトの面積分率が5%以下であることを特徴とする、請求項1~6の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、Zn/Al/MgZn2三元共晶組織の面積分率が5%以下であることを特徴とする、請求項1~7の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、塊状Zn相の面積分率が10%以下であることを特徴とする、請求項1~8の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、板状のZn/MgZn2ラメラ組織の面積分率が10%以下であることを特徴とする、請求項1~9の何れか1項に記載のめっき鋼板。
- 前記めっき層の前記表面において、Mg2Si相の面積分率が10%以下であることを特徴とする、請求項1~10の何れか1項に記載のめっき鋼板。
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002302749A (ja) * | 2001-04-06 | 2002-10-18 | Sumitomo Metal Ind Ltd | 耐かじり性に優れた溶融Zn−Al系合金めっき鋼板とその製造方法 |
JP2009120947A (ja) | 2007-10-24 | 2009-06-04 | Nippon Steel Corp | 耐食性と溶接性に優れる亜鉛系合金めっき鋼材及び耐食性に優れる塗装鋼材 |
JP4579715B2 (ja) | 2004-03-08 | 2010-11-10 | 日新製鋼株式会社 | 耐食性,塗膜密着性,接着性に優れた化成処理鋼板 |
JP2015214747A (ja) | 2014-04-23 | 2015-12-03 | Jfeスチール株式会社 | 溶融Al−Zn系めっき鋼板及びその製造方法 |
JP2018532889A (ja) * | 2015-10-26 | 2018-11-08 | ポスコPosco | 曲げ加工性に優れた亜鉛合金めっき鋼板及びその製造方法 |
JP2019080288A (ja) | 2017-10-27 | 2019-05-23 | 富士通株式会社 | ネットワーク装置の時刻同期方法、ネットワーク装置、及び、ネットワークシステム |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4136286B2 (ja) * | 1999-08-09 | 2008-08-20 | 新日本製鐵株式会社 | 耐食性に優れたZn−Al−Mg−Si合金めっき鋼材およびその製造方法 |
JP5230318B2 (ja) | 2008-09-18 | 2013-07-10 | 新日鐵住金株式会社 | 高耐食性を有し加工性に優れためっき鋼材およびその製造方法 |
CN103476961B (zh) | 2011-07-20 | 2016-04-06 | 新日铁住金株式会社 | 板 |
CN103507324B (zh) * | 2012-06-20 | 2015-06-03 | 鞍钢股份有限公司 | 一种合金化锌铝镁镀层钢板及其生产方法 |
JP6676555B2 (ja) | 2017-01-18 | 2020-04-08 | 日鉄日新製鋼株式会社 | 黒色めっき鋼板の製造方法およびその製造装置 |
MX2019008677A (es) * | 2017-01-27 | 2019-11-08 | Nippon Steel Corp | Producto de acero con recubrimiento metalico. |
CN111868290B (zh) | 2018-03-20 | 2022-05-31 | 日本制铁株式会社 | 热冲压成型体 |
-
2020
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002302749A (ja) * | 2001-04-06 | 2002-10-18 | Sumitomo Metal Ind Ltd | 耐かじり性に優れた溶融Zn−Al系合金めっき鋼板とその製造方法 |
JP4579715B2 (ja) | 2004-03-08 | 2010-11-10 | 日新製鋼株式会社 | 耐食性,塗膜密着性,接着性に優れた化成処理鋼板 |
JP2009120947A (ja) | 2007-10-24 | 2009-06-04 | Nippon Steel Corp | 耐食性と溶接性に優れる亜鉛系合金めっき鋼材及び耐食性に優れる塗装鋼材 |
JP2015214747A (ja) | 2014-04-23 | 2015-12-03 | Jfeスチール株式会社 | 溶融Al−Zn系めっき鋼板及びその製造方法 |
JP2018532889A (ja) * | 2015-10-26 | 2018-11-08 | ポスコPosco | 曲げ加工性に優れた亜鉛合金めっき鋼板及びその製造方法 |
JP2019080288A (ja) | 2017-10-27 | 2019-05-23 | 富士通株式会社 | ネットワーク装置の時刻同期方法、ネットワーク装置、及び、ネットワークシステム |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2022080004A1 (ja) * | 2020-10-16 | 2022-04-21 | ||
JP7401827B2 (ja) | 2020-10-16 | 2023-12-20 | 日本製鉄株式会社 | 溶融Zn系めっき鋼板 |
EP4223897A4 (en) * | 2020-11-18 | 2024-04-10 | Nippon Steel Corporation | CLAD STEEL MATERIAL |
US20230193425A1 (en) * | 2021-07-09 | 2023-06-22 | Nippon Steel Corporation | Plated steel |
US11781200B2 (en) * | 2021-07-09 | 2023-10-10 | Nippon Steel Corporation | Plated steel |
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