Method of making tempered shaped part

Abstract

A method of making a tempered part has the steps of first heating a metal blank to above a first predetermined temperature and then preshaping the heated blank while still above the first temperature. The preshaped blank is then reheated to a second tempering temperature, and the reheated blank is given its final shape while still above the second temperature in a press. The blank with its final shape is cooled below the second tempering temperature while still in the press.

1 . A method of making a tempered part, the method comprising the steps of sequentially:
 heating a metal blank to above a first predetermined temperature;   preshaping the heated blank while still above the first temperature;   reheating the preshaped blank to a second tempering temperature;   final shaping the reheated blank while still above the second temperature in a press; and   cooling the blank below the second tempering temperature while still in the press.   
     
     
         2 . The method defined in  claim 1  wherein the blank is cooled in the press by contact with cooled tools of the press. 
     
     
         3 . The method defined in  claim 2  wherein the first temperature is below the second temperature. 
     
     
         4 . The method defined in  claim 1  wherein the preshaping is done in several steps. 
     
     
         5 . The method defined in  claim 1 , further comprising the step after preshaping and before reheating of:
 trimming the workpiece.   
     
     
         6 . The method defined in  claim 1 , further comprising the step before heating to the first temperature of:
 providing the metal blank with an aluminum coating.   
     
     
         7 . The method defined in  claim 6 , further comprising the step after final shaping of
 using the finally shaped part as a longitudinal vehicle-chassis beam, the blank being made of 22MnB5 steel and having a generally U-shaped profile and a nonstraight longitudinal extension.