Method for Manufacturing Hot-Pressed Member

Abstract

A method for manufacturing a hot-pressed member The method includes heating a zinc-based coated steel sheet to a temperature range from an Ac3 transformation temperature to 1000 ° C., performing hot pressing work, and performing cooling, in which a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating step is performed.

1 . A method for manufacturing a hot-pressed member having an excellent surface appearance, the method comprising:
 heating a zinc-based coated steel sheet to a temperature range from an Ac3 transformation temperature to 1000° C.,   performing hot pressing work, and   performing cooling,   wherein a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating step is performed.   
     
     
         2 . A method for manufacturing a hot-pressed member having an excellent surface appearance, the method comprising:
 performing cold pressing work on a zinc-based coated steel sheet,   heating the zinc-based coated steel sheet to a temperature range form an Ac3 transformation temperature to 1000° C., and   cooling the heated steel sheet,   wherein a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating step is performed.   
     
     
         3 . The method for manufacturing a hot-pressed member according to  claim 1 , wherein;
 the zinc-based coated steel sheet is a Zn—Ni-alloy-coated steel sheet having a coating layer on one or both sides of the Zn—Ni-alloy-coated steel sheet, and   the coating layer has a chemical composition containing 10 mass % to 25 mass % of Ni with the balance being Zn and inevitable impurities, and a coating weight of the coating layer per side of the zinc-based coated steel sheet is 10 g/m 2  to 90 g/m 2 .   
     
     
         4 . The method for manufacturing a hot-pressed member according to  claim 2 , wherein:
 the zinc-based coated steel sheet is a Zn—Ni-alloy-coated steel sheet having a coating layer on one or both sides of the Zn—Ni-alloy-coated steel sheet, and   the coating layer has a chemical composition containing 10 mass % to 25 mass % of Ni with the balance being Zn and inevitable impurities, and a coating weight of the coating layer per side of the zinc-based coated steel sheet is 10 g/m 2  to 90 g/m 2 .