Method for manufacturing galvanized steel sheet for hot stamping, hot-dip galvannealed steel sheet for hot stamping and method for manufacturing same, and hot stamped component

Abstract

Provided is a method for producing a plated steel sheet with high Si content for hot stamping, which is capable of suppressing the generation of unplated portions, while maintaining high bonding strength in a welded part in cases where a galvanized steel sheet containing a large amount of Si, namely, 0.7% or more of Si is used for hot stamping applications. In this production method, a hot-rolled pickled steel sheet or cold-rolled steel sheet containing 0.10-0.5% by mass of C, 0.7-2.5% by mass of Si, 1.0-3% by mass of Mn, and 0.01-0.5% by mass of Al is annealed in a reducing atmosphere and then plated, thereby producing a galvanized steel sheet for hot stamping. This method for producing a galvanized steel sheet for hot stamping is characterized in that the annealing is carried out within the range of 500 to 700° C. for 30 to 270 seconds.

1 . A method for manufacturing a galvanized steel sheet, the method comprising:
 annealing a hot-rolled pickled steel sheet or a cold-rolled steel sheet under a reducing atmosphere, thereby forming an annealed steel sheet; and   galvanizing the annealed steel sheet, thereby forming a galvanized steel sheet,   wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet comprises: C in a content of 0.10% to 0.5%; Si in a content of 0.7% to 2.5%; Mn in a content of 1.0% to 3%; and Al in a content of 0.01% to 0.5%, in percent by mass, and   wherein the annealing is performed at a temperature of 500° C. to 700° C. for 30 to 270 seconds.   
     
     
         2 . The method according to  claim 1 ,
 wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet further comprises B in a content of 0.005% or less (excluding 0%).   
     
     
         3 . The method according to  claim 1 ,
 wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet further comprises Ti in a content of 0.10% or less (excluding 0%).   
     
     
         4 . The method according to  claim 1 ,
 wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet further comprises Cr and Mo in a content of 1% or less (excluding 0%) in total.   
     
     
         5 . The method according to  claim 1 ,
 wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet further comprises Nb, Zr, and V in a content of 0.1% or less (excluding 0%) in total.   
     
     
         6 . The method according to  claim 1 ,
 wherein the hot-rolled pickled steel sheet or the cold-rolled steel sheet further comprises Cu and Ni in a content of 1% or less (excluding 0%) in total.   
     
     
         7 . The method according  claim 1 ,
 wherein the galvanized steel sheet is a hot-dip galvanized steel sheet or a hot-dip galvannealed steel sheet.   
     
     
         8 - 19 . (canceled) 
     
     
         20 . The method according to  claim 1 , further comprising alloying the galvanized steel sheet. 
     
     
         21 . The method according to  claim 20 , wherein an oxygen concentration at an interface between a hot-dip galvannealed layer and a base steel sheet of the alloyed galvanized steel sheet is 0.50% or less. 
     
     
         22 . The method according to  claim 20 , wherein the alloying is performed at a temperature of 560° C. to 750° C. 
     
     
         23 . The method according to  claim 20 , further comprising re-annealing the alloyed steel sheet at a temperature of 400° C. to 750° C. 
     
     
         24 . The method according to  claim 22 , wherein a Fe concentration in a galvannealed layer of the alloyed steel sheet is 16% or more. 
     
     
         25 . The method according to  claim 21 , wherein a Fe concentration in the galvannealed layer of the re-annealed steel sheet is 16% or more.