Aluminum alloy plated steel sheet, hot-formed member, and method for manufacturing these.

Abstract

The present invention provides aluminum alloy plated steel sheets, hot-formed components, and methods for manufacturing these components, all exhibiting excellent surface quality and weldability. [Solution] The aluminum alloy plated steel sheet comprises a base steel sheet and an aluminum alloy plating layer formed on the base steel sheet, wherein the aluminum alloy plating layer contains, by weight %, Zn: 21-35%, Si: 1-6.9%, Fe: 2-12%, with the remainder being Al and other unavoidable impurities.

Claims

1. Raw steel sheet; and Includes an aluminum alloy plating layer formed on the base steel sheet; The aluminum alloy plating layer has a composition of Zn: 21-35% and Si: 1-6.9% by weight. Aluminum alloy containing %, Fe: 2-12%, the remainder being Al and other unavoidable impurities. Steel plate.

2. The aforementioned base steel sheet has the following composition by weight %, C: 0.15-0.39%, Mn: 0.5-3%, B: 0 0.01% or less (including 0%), Ti: 0.1% or less (including 0%), remainder Fe and others The aluminum alloy plated steel sheet according to claim 1, which contains the unavoidable impurities.

3. The aluminum alloy plating layer further comprises Mg: 1.4% or less, as described in claim 1. Aluminum alloy plated steel sheet.

4. The aluminum alloy plating layer has an Al / (Zn+Si) ratio of 1.3 to 2.

6. Aluminum alloy plated steel sheet as described in item 1. (However, the above Al, Zn, and Si content units are in weight percent.)

5. The material comprises a base steel sheet and an aluminum alloy plating layer formed on the base steel sheet. The aluminum alloy plating layer consists of, by weight, Zn: 21-35%, Si: 1-6.9%, and F e: 2-12%, Mg: 1.2% or less (including 0%), remainder Al and other unavoidable impurities A hot-formed member obtained by hot-forming an aluminum alloy plated steel sheet containing a material, In terms of area percentage, martensite: 90% or more, with the remainder being one of ferrite or bainite. A hot-formed member having a microstructure including the above.

6. The hot-formed member has a tensile strength of 1200 MPa or more, as described in claim 5. Shaped member.

7. The stage of preparing the base steel sheet; and The aforementioned base steel sheet is immersed in a plating bath at 580 to 680°C to coat the surface of the base steel sheet with aluminum. The process includes the step of forming a um alloy plating layer; The aforementioned plating bath consists of, by weight, Zn: 23-40%, Si: 1-8%, and the remainder being Al and its A method for manufacturing aluminum alloy plated steel sheets containing other unavoidable impurities.

8. The aforementioned base steel sheet has the following composition by weight %, C: 0.15-0.39%, Mn: 0.5-3%, B: 0 0.01% or less (including 0%), Ti: 0.1% or less (including 0%), remainder Fe and others A method for manufacturing an aluminum alloy plated steel sheet according to claim 7, comprising the unavoidable impurities.

9. The aluminum alloy according to claim 7, wherein the plating bath further comprises Mg: 1.4% or less. A method for manufacturing plated steel sheets.

10. The plating bath has an Al / (Zn+Si) ratio of 1.3 to 2.6, as described in claim 7. A method for manufacturing aluminum alloy plated steel sheets. (However, the content units for Al, Zn, and Si mentioned above are in weight percent.)

11. Before the step of forming the aluminum alloy plating layer, the base steel sheet is 650 to 850 Manufacturing of an aluminum alloy plated steel sheet according to claim 7, further comprising the step of heat treatment at °C. method.

12. The aforementioned heat treatment is performed using hydrogen gas at a volume percentage of 25% or less (including 0%) and the remainder being nitrogen gas. The manufacturing of the aluminum alloy plated steel sheet according to claim 11, carried out in a reducing atmosphere. Construction method.

13. The temperature of the plating bath is between the melting point of the plating solution + 20°C and the melting point of the plating solution + 80°C. A method for manufacturing aluminum alloy plated steel sheets as described in item 7.

14. The temperature at which the base steel sheet enters the plating bath is between the temperature of the plating bath + 5°C and the temperature of the plating bath + A method for manufacturing an aluminum alloy plated steel sheet according to claim 7, wherein the temperature is 50°C.

15. After the step of forming the aluminum alloy plating layer, The aluminum alloy plating according to claim 7, further comprising the step of controlling the amount of plating deposited. A method for manufacturing steel plates.

16. The aforementioned plating adhesion amount is 15 to 150 g / m² on a single-sided basis. ２ The aluminum according to claim 15. A method for manufacturing nium alloy plated steel sheets.

17. Aluminum alloy plating obtained by the method described in any one of claims 7 to 16 The step of heating the steel plate to an Ac3 temperature or higher; The heated aluminum alloy plated steel sheet is hot-formed using a mold to form a hot-formed member. The stage of obtaining; and Manufacturing of a hot-formed member, including the step of cooling the molded member at a cooling rate of 10°C / s or more. method.

18. Before the aforementioned heating, the step of manufacturing the aluminum alloy plated steel sheet as a blank is performed. A method for manufacturing a hot-formed member according to claim 17, which includes the above.

19. The method for manufacturing a hot-formed member according to claim 17, wherein the heating is performed for 1 to 15 minutes.

20. When transferring the heated aluminum alloy plated steel sheet to the mold, the transfer time is 2 A method for manufacturing a hot-formed member according to claim 17, wherein the process takes less than 0 seconds.

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