Regular Article

Hot forming with a nonuniform temperature field using die partition cooling

National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, PR China

^* e-mail: pengyan@ysu.edu.cn

Received: 2 October 2018
Accepted: 22 August 2019

Abstract

High strength steel hot forming technology plays an important role in achieving lightweight vehicles, improving the safety of vehicles. The tensile strength of the blank formed by traditional hot forming process is as high as 1500–2000 MPa, the strength of the formed blank is high, but the elongation is usually low and comprehensive mechanical property is not high. In this article, the process control of material gradient properties hot forming technology is summarized through the analysis of strengthening mechanism of gradient distribution hot forming technology. Based on the traditional hot forming technology, a new hot forming technology based on partition cooling to achieve material property gradient distribution is proposed. By changing the cooling rate of blank in different zones is different, and the gradient distribution of material properties is finally obtained. The DEFORM is used to analyze the hot forming process of the blank under the nonuniform temperature field of the partition cooling. A set of partition cooling hot forming die was designed independently to verify the experimental results. The evolution mechanism of microstructure and its effect on material properties during hot forming under nonuniform temperature field with partition cooling were revealed.