Study of continuous cooling transition curve of Si-Mn-Cr-Mo ultra high strength steel
YAO Xiu-quan1��YANG Jian-ying2��HAN Dan2��GAO Zhan-yong1
��1. College of Materials and Metallurgy�� Inner Mongolia University of Science and Technology�� Baotou 014010�� China 2. Baotou Institute of Materials Research�� Shanghai Jiao Tong University�� Baotou 014010�� China��
Abstract��Based on the measurement of the different dilatometric curves of Si-Mn-Cr-Mo ultra-high strength steel during continuous cooling on the condition of different cooling rates by using L78 quenching dilatometer�� and combined with the optical microstructure analysis and hardness measurement�� the continuous cooling transformation ��CCT�� curve of undercooled austenite for the steel was obtained��The effect of cooling rate on the microstructure evolution was investigated by the CCT curve and the analysis results of the optical microscope and microhardness. The results showed that the microstructure of the tested steel consisted of ferrite ��F�� and bainite ��B�� after phase transition at the cooling rate of 0.04 ��/s-0.1 ��/s�� the phase transition structure became into bainite ��B�� and martensite ��M�� at the cooling rate of 0.2 ��/s-2 ��/s�� the martensite ��M�� was observed at the cooling rate of more than 3 ��/s. With the increase of cooling rate�� the hardness value also increased. The results provided an important theoretical basis for the controlled cooling process of the steel.
CCT Curves of Low-Carbon Mn-Si Steels and Development of Water-Cooled Bainitic Steels[J]. Journal of Iron and Steel Research(International),2010,(03):46-50
2018, Vol. 36 
