# US 11,897,229 B2 · Aluminum alloy-plated steel sheet having excellent workability and corrosion resistance and method for manufacturing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,897,229 B2 - Document ID: US11897229B2 - Status: Granted - Kind: B2 - Application number: 17/784,729 - Filed: 2020-12-18 - Published: 2023-01-19 - Granted: 2024-02-13 - Earliest claimed: 2019-12-20 - Assignees: Posco - Applicants: Posco - Inventors: Suk-Kyu Lee; Hyeon-Seok Hwang; Myung-Soo Kim - Web page: https://patentgrep.com/patent/US11897229B2 ## CPC - B32B 15/012: {one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy} - C21D 1/613: Gases; Liquefied or solidified normally gaseous material - C21D 1/673: for die quenching - C21D 8/02: during manufacturing of plates or strips (C21D8/12 takes precedence) - C21D 8/0278: involving a particular surface treatment (C21D8/0294 takes precedence) - C21D 9/46: for sheet metals - C22C 21/02: with silicon as the next major constituent - C22C 21/10: with zinc as the next major constituent - C22C 38/02: containing silicon - C22C 38/04: containing manganese - C22C 38/14: containing titanium or zirconium - C23C 2/12: Aluminium or alloys based thereon - C23C 2/26: After-treatment (C23C2/14 takes precedence) - C23C 2/261: {in a gas atmosphere, e.g. inert or reducing atmosphere} - C23C 2/29: {Cooling or quenching} - C23C 2/40: Plates; Strips - C23C 28/02: only coatings {only including layers} of metallic material - C23C 28/023: {only coatings of metal elements only} - C23C 28/322: {only coatings of metal elements only} - C23C 28/345: {with at least one oxide layer} - B32B 2307/718: Weight, e.g. weight per square meter - B32B 2307/732: Dimensional properties - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - 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 (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - C22C: ALLOYS (treatment of alloys C21D, C22F) - 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 (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract The present disclosure relates to an aluminum alloy-plated steel sheet having excellent workability and corrosion resistance and a method for manufacturing the same, and more particularly, to an aluminum alloy-plated steel sheet preventing microcracks generated during hot forming and has excellent seizure resistance and corrosion resistance, and a method for manufacturing the same. ## Claims ### Claim 1 An aluminum alloy-plated steel sheet comprising: a base steel sheet; an alloy-plated layer formed on the base steel sheet; and an unalloy-plated layer formed on the alloy-plated layer, wherein the alloy-plated layer contains, by wt %, 35 to 50% of Fe, 1 to 20% of Zn, 0.1 to 1.5% of Si, and a balance of Al and unavoidable impurities, the unalloy-plated layer contains, by wt %, 1 to 30% of Zn, 0.1 to 1.8% of Si, and a balance of Al and unavoidable impurities, and an interface roughness Ra, between the alloy-plated layer and the base steel sheet is 2.5 μm or less. ### Claim 2 (depends on 1) The aluminum alloy-plated steel sheet of claim 1, wherein a thickness of the alloy-plated layer is 5 to 25 μm, and a thickness of the unalloy-plated layer is 1 to 12 μm. ### Claim 3 (depends on 1) The aluminum alloy-plated steel sheet of claim 1, wherein a content of Zn in the unalloy-plated layer is higher than a content of Zn in the alloy-plated layer. ### Claim 4 (depends on 1) The aluminum alloy-plated steel sheet of claim 1, wherein a thickness of the alloy-plated layer is 50% or more of the entire thickness of the alloy-plated layer and the unalloy-plated layer. ### Claim 5 (depends on 1) The aluminum alloy-plated steel sheet of claim 1, wherein the base steel sheet contains, by wt %, 0.05 to 0.3% of C, 0.1 to 1.5% of Si, 0.5 to 8% of Mn, 50 ppm or less of B, and a balance of Fe and unavoidable impurities. ### Claim 6 (depends on 1) The aluminum alloy-plated steel sheet of claim 1, wherein a content of Si in the alloy-plated layer is 0.1 to 0.5% in terms of wt %. ### Claim 7 (depends on 1) A hot-formed member obtained by subjecting the aluminum alloy-plated steel sheet of claim 1 to hot press forming. ### Claim 8 A method for manufacturing an aluminum alloy-plated steel sheet used for hot press forming, the method comprising: preparing a base steel sheet; dipping the base steel sheet in an aluminum plating bath that contains, by wt %, 3 to 30% of Zn, 0.1 to 1.5% of Si, and a balance of Al and unavoidable impurities to obtain an aluminum-plated steel sheet; performing cooling by supplying air heated to 200 to 300° C. to the aluminum-plated steel sheet after the aluminum plating to form an oxide film on a surface of the aluminum-plated steel sheet; and obtaining an aluminum alloy-plated steel sheet by on-line alloying in which a heat treatment is performed after the cooling while maintaining the aluminum-plated steel sheet in a heating temperature range of 550° C. or higher and lower than 650° C. for 1 to 20 seconds. ### Claim 9 (depends on 8) The method of claim 8, further comprising, after the alloy treatment, performing cooling. ### Claim 10 (depends on 8) The method of claim 8, wherein a plating weight in the plating is 20 to 100 g/m2 per surface. ### Claim 11 (depends on 9) The method of claim 9, wherein the cooling after the alloy treatment is air cooling. ### Claim 12 (depends on 8) The method of claim 8, wherein the oxide film is formed on the surface of the aluminum-plated steel sheet at a thickness of 10% or more of the entire thickness of a hot-dip aluminum-plated layer.