Production method and die for hot stamped member comprising local soft region, and hot stamped member

Abstract

A method and die for a hot stamped member comprising a local soft region, and a hot stamped member, is provided. The method comprises moving an austenitized slab into a TTP thermoforming die, the TTP thermoforming die pressing out several ribs at a soft region position, moving a thermoformed member from the TTP thermoforming die into a shaping die, and pressing, when pressure is applied, the ribs of the soft region lower and wider until they are the same shape as a digital product model. A soft region is provided with ribs during thermoforming, and the ribs shrink during shaping to compensate for a dimensional change caused by the soft region cooling and shrinking, thereby not only ensuring the performance of a soft region of a part, but also solving the problems of severe dimensional deviation and poor dimensional stability after TTP formation.

What is claimed is: 
     
         1 . A production method for a hot stamped member comprising a local soft region, the method comprising:
 heating a slab in a heating furnace to fully austenitize the same;   moving the slab into a TTP thermoforming die, the TTP thermoforming die pressing out several ribs at a soft region, and the height and the width of the ribs depending on the length to which the soft region cools and shrinks;   rapidly moving a thermoformed member from the TTP thermoforming die into a shaping die, and shaping the soft region in the shaping die, the ribs at the soft region being pressed lower and wider when pressure is applied, until they are the same shape as a digital product model, and the die removal temperature being lower than 80° C.; and   removing a shaped part from a shaping press.   
     
     
         2 . The production method for a hot stamped member comprising a local soft region according to  claim 1 , wherein the TTP thermoforming die has soft and hard regions, and the soft region employs an in-die heating TTP process, the die removal temperature thereof being higher than the die removal temperature of the hard region by 250° C. to 350° C. 
     
     
         3 . The production method for a hot stamped member comprising a local soft region according to  claim 1 , wherein the pressure is applied by an insert mounted in the shaping die, to press the ribs of the soft region lower and wider until they are the same shape as the digital product model. 
     
     
         4 . The production method for a hot stamped member comprising a local soft region according to  claim 1 , wherein the ribs of the soft region are pressed lower and wider under the pressure so as to be flush with a hard region of an adjacent section. 
     
     
         5 . A production die for a hot stamped member comprising a local soft region, comprising:
 a TTP thermoforming die and a shaping die,   several ribs protruding from the TTP thermoforming die in a soft region, the height and the width of the ribs depending on the length to which the soft region cools and shrinks, and the shaping die pressing, when pressure is applied, the ribs of the soft region lower and wider until they are the same shape as a digital product model.   
     
     
         6 . The production die for a hot stamped member comprising a local soft region according to  claim 5 , wherein the shaping die applies pressure by an insert mounted in the die. 
     
     
         7 . The production die for a hot stamped member comprising a local soft region according to  claim 6 , wherein a cooling water channel is provided in the insert. 
     
     
         8 . The production die for a hot stamped member comprising a local soft region, wherein the production die implements the production method according to  claim 1 . 
     
     
         9 . A hot stamped member, comprising a local soft region, wherein the hot stamped member is produced by the production method according to  claim 1 .