1. Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China; 2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production, Shougang Group Co., Ltd., Beijing 100043, China; 3. Manufacturing Department, Beijing Shougang Co., Ltd., Tangshan 064404, Hebei, China; 4. Qianshun Technology Center, Shougang Group Co., Ltd., Tangshan 064404, Hebei, China
Abstract：Microstructures and properties of 500 MPa grade V-N microalloyed hot stamped axle housing steel were analyzed by OM, SEM and TEM. The results showed that the yield strength, tensile strength, and elongation of the tested steel reached 373 MPa, 544 MPa, and 25.5%, respectively. The low-temperature impact energy at -60 ℃ reached 145 J. The microstructure of the tested steel was mainly a mixed structure of ferrite and a small amount of pearlite. There were a large number of precipitates on the ferrite matrix which were mainly spherical, there were two types of precipitates, and one was large particles with a size of 30-50 nm, the spectral analysis showed that it was VCN, and the other was small particles with a size below 20 nm, and the spectral analysis showed that it was VC. After hot stamping, the yield strength and tensile strength of the tested steel could reach 305 and 450 MPa, respectively, and decline rates of yield strength and tensile strength were controlled at 18.2% and 17.3%, respectively.
2021, Vol. 31 
