Transactions of Materials and Heat Treatment

Title：Variable strength hot stamping process realized by gradient heating to regulate microstructure

Authors： Wang Yilin1 Fang Dongyu1 Liu Peixing2 Zhu Bin1 Zhang Yisheng1

Unit：

KeyWords：

ClassificationCode：TG115.2

year,vol(issue):pagenumber：2021,46(9):197-203

Abstract：

A variable-strength hot stamping process was developed to regulate the microstructures and mechanical properties of parts, and the induction coils were used to perform gradient heating of the blank to austenitize the local area, and then regulate the microstructures of each area after quenching to obtain the variable-strength parts. Furthermore, for the hot stamping steels in annealed state and cold rolled state, experiments were applied to study the process. The microstructure of softened zone is pearlite and ferrite, and the tensile strength and elongation of the annealed and cold-rolled steel sheets are 490 MPa, 32% and 940.4 MPa, 4.2%, respectively. However, the microstructure of high-strength zone is all martensite, and the tensile strength and elongation of annealed and cold-rolled steel sheets are 1532 MPa, 9.1% and 1485.1 MPa, 8.4%, respectively. But, the hardness of transition zone gradually decreases from high-strength zone to softened zone, and the performance is basically smoothly transitioned. The results show,for two kinds of steel with different supply condition, parts with variable strength distribution can be obtained by the method of microstructure regulation.

Funds：

国家自然科学基金资助项目（U1760205）；国家科技重大专项（2018ZX04023001）

王义林（1968-），男，博士，副教授 E-mail：wangyilin@hust.edu.cn 通信作者：朱彬（1983-），男，博士，副教授 E-mail：zhubin26@hust.edu.cn

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