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Hot stamping is a process that blanks are formed at high temperature with subsequent quenching under pressure. It is accompanied by rapid temperature reduction，significant material yield strength enhancement as well as elastic modulus increase. At 300-400 ℃, the austenite transforms to martensite,meanwhile the stress and strain field change gradually. When the die opens at the end of hot stamping,the workpiece will have some amount of springback. For this complicated process,the influences of holding time and sheet thickness on hat-shaped piece springback were investigated, and the springback of hat-shaped part under different hot stamping processes was measured.The results show that the springback decreases with the increasing of press holding time, and eventually stabilizes in a relative range. The thickness of blank becomes thinner, the amount of springback becomes less.
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