Effect of V Addition on Microstructure and Mechanical Properties in C–Mn–Si Steels after Quenching and Partitioning Processes

Metals

Zheng-Zhi Zhao¹  Gong-Ting Zhang¹  Di Tang¹  Na-Qiong Zhu²  Lin Li³  Bo-Wei Sun³  Zhi-Wang Zheng⁴ 

[1] Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China;College of International Vocational Education, Shanghai Polytechnic University, Shanghai 201209, China;School of Material Science and Engineering, Shanghai University, Shanghai 200444, China;State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China;

关键词: V microalloyed Q&P steel;    microstructure;    mechanical properties;    precipitate size distribution;    work hardening rate;   

DOI  :  10.3390/met11081306

来源: DOAJ

【 摘 要 】

Three C-Si-Mn Q&P steels with different V addition after one-step and two-step quenching and partitioning (Q&P) processes were investigated by means of optical microstructure observation, X-ray diffraction (XRD) measurement, transmission electron microscopy (TEM) characterization and particle size distribution (PSD) analysis. The effect of V addition on strength and ductility of the steels was elucidated by comparative analysis on the microstructure and mechanical properties as functions of partitioning time and temperature. For one-step Q&P treatment, the mechanical properties were mainly controlled by the tempering behavior of martensite during partitioning. V addition was helpful to mitigate the deterioration of mechanical properties by precipitation strengthening and grain refinement strengthening. For two-step Q&P treatment, the satisfying plasticity was attributed to the transformation-induced plasticity (TRIP) effect of retained austenite maintaining the high work hardening rate at high strain regime. The higher volume fraction of retained austenite with high stability resulted from the refined microstructure and the promoted carbon partitioning for the steel with 0.16 wt% V addition. However, the carbon consumption due to the formation of VC carbides led to the strength reduction of tempered martensite.

【 授权许可】

Unknown