Effect of Two-Step Austempering Process on Transformation Kinetics of Nanostructured Bainitic Steel

Materials

Leilei You¹  Xuemei Li²  Zhinan Yang²  Changhong Guo³  Xiaoyan Long⁴  Chunhe Chu⁴  Fucheng Zhang⁴  Yuman Qin⁴ 

[1] Luoyang LYC Bearing Co., Ltd., Luoyang 471039, China;National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, China;School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China;State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China;

关键词: nanostructured bainite;    bearing steel;    two-step austempering process;    phase transformation;   

DOI  :  10.3390/ma12010166

来源: DOAJ

【 摘 要 】

The two-step austempering process has been reported to be an effective method to accelerate the bainitic transformation process by introducing martensite (Q-M-B). However, in this study, it was found that the Q-M-B process reduced the incubation time, but the transformation duration remained nearly unchanged. The notably reduced activation energy barrier for nucleation of bainitic ferrite on the preformed martensite should be responsible for the reduced duration time of the Q-M-B process. A process that both of the two steps were above, Ms (Q-B-B), has been demonstrated to increase transformation rate and improve the amount of bainitic ferrite, which probably results from the additional hysteresis free energy provided by the first quenching process.

【 授权许可】

Unknown