A novel method for the spring-back analysis of a hot stamping steel

Journal of Materials Research and Technology

M. Amirthalingam¹  Melwin Sajan²  Uday Chakkingal³ 

[1] Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, 600 036, India;Corresponding author.;Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, 600 036, India;

关键词: Hot stamping;    Advanced high strength steels;    Cooling rate;    V-bending;    Spring-back;    Phase transformation;   

DOI  :  

来源: DOAJ

【 摘 要 】

Spring-back of sheet metal affects the dimensional accuracy of the components after stamping and has to be eliminated or corrected. Advanced high strength steels (AHSS) are prone to spring-back while forming at ambient temperatures. Hot stamping process is an effective technique to reduce the spring-back upon forming. The forming temperatures and the phase transformations associated with quenching are known to influence the spring-back. However, the detailed experimental analysis on spring-back behaviour is limited due to the difficulty in physically simulating the thermal-mechanical conditions prevailing in a typical hot forming process. In the present work, a novel V-bending technique is presented for effectively measuring the spring-back using a thermal-mechanical simulator, Gleeble™. V-bending is carried out by applying a compressive force along the longitudinal plane of AHSS steel strips at forming temperatures. Upon V-bending, samples were cooled at different cooling rates while maintaining the forming loads to simulate die quenching. Results indicate that the spring-back decreases and becomes close to zero (at a cooling rate of 20 K s−1) with an increase in cooling rate for a hot stamping steel. Further, an increase in cooling rate results in spring-forward owing to the formation of an increased volume fraction of martensite.

【 授权许可】

Unknown