Method of making a structural member for use in the automobile industry

Abstract

In a method of making a structural member for the automobile industry, a blank of boron steel is pre-formed at ambient temperature into an intermediary part of a configuration which substantially corresponds to an end shape of a finished structural member. The intermediary part is then coated with aluminum or an aluminum alloy and exposed to a temperature above the upper transformation line in the TTT curve. Subsequently, the intermediary part is formed in a mold into the finished structural member while being hardened at the same time.

What is claimed is:  
     
         1 . A method of making a structural member for use in the automobile industry, comprising the steps of: 
 shaping a blank of boron steel at ambient temperature into an intermediary part of a configuration which substantially corresponds to an end shape of a finished structural member;    coating the intermediary part with aluminum or an aluminum alloy;    heating the intermediary part to a temperature above the upper transformation line in a TTT curve; and    forming the intermediary part in a mold into the finished structural member at simultaneous hardening of the structural member.    
     
     
         2 . The method of  claim 1 , wherein the coating step is carried out at a temperature of about 650° C.  
     
     
         3 . The method of  claim 1 , wherein the coating step is carried out in a dipping process.  
     
     
         4 . The method of  claim 1 , wherein the temperature above the upper transformation line in a TTT curve is about 930° C.  
     
     
         5 . A method of making a structural member for use in the automobile industry, comprising the steps of: 
 shaping a blank of boron steel at ambient temperature into an intermediary part of a configuration which substantially corresponds an end shape of a finished structural member;    heating the intermediary part to a temperature above the upper transformation line in the TTT curve;    coating the intermediary part in a melt at a temperature above the upper transformation line in the TTT curve with aluminum or an aluminum alloy; and    forming the intermediary part in a tool into the finished structural member at simultaneous hardening of the structural member.    
     
     
         6 . The method of  claim 5 , wherein the temperature above the upper transformation line in a TTT curve is about 930° C.  
     
     
         7 . A method of making a structural member for use in the automobile industry, comprising the steps of: 
 shaping a blank of boron steel at ambient temperature into an intermediary part of a configuration which substantially corresponds an end shape of a finished structural member;    placing the intermediary part in a melt of aluminum or an aluminum alloy at a temperature above the upper transformation line in the TTT curve;    coating the intermediary part in the melt; and    forming the intermediary part in a mold into the finished structural member at simultaneous hardening of the structural member.    
     
     
         8 . The method of  claim 7 , wherein the temperature above the upper transformation line in a TTT curve is about 930° C.