The Study of Hardness Evolution during the Tempering Process of 38MnB5Nb Ultra-High-Strength Hot Stamping Steel: Experimental Analysis and Constitutive Models
Ping Luo,
Xianjun Li,
Wenliang Zhang,
Zhunli Tan,
Minghao Zhang,
Kaize Wang,
Pengdi Hou,
Junjie Liu,
Xiao Liang
Affiliations
Ping Luo
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Xianjun Li
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Wenliang Zhang
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Zhunli Tan
Material Science & Engineering Research Center, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
Minghao Zhang
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Kaize Wang
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Pengdi Hou
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Junjie Liu
Beijing Research Institute of Mechanical and Electrical Technology Ltd., Beijing 100083, China
Xiao Liang
The College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
To elucidate the hardness evolution behaviors for 38MnB5Nb ultra-high-strength hot stamping steel, a series of tempering processes with varying tempering temperatures and times were carried out with a dilatometer. Meanwhile, the hardness of each sample was measured after dilatometer experiments. The results indicated that the tempering process parameters (including the tempering temperature and time) play an important role in the hardness of the studied steel. The hardness of 38MnB5Nb ultra-high-strength hot stamping steel at the quenched state is about 580 Hv, while it is 240 Hv for the quasi-annealed state. As the tempering time extends, the hardness is decreased sharply at the initial stage; then, the hardness is decreased in a quasi-linear trend with a slight slope; finally, the hardness almost keeps a constant value, which depends on the tempering temperature. In addition, the tempering process has a big effect on the mechanical properties of 38MnB5Nb ultra-high-strength hot stamping steel by increasing the product of the strength and elongation by about 40%.
