Precipitation behavior and martensite lath coarsening during tempering of T/P92 ferritic heat-resistant steel
来源期刊：International Journal of Minerals Metallurgy and Materials2014年第5期
论文作者：Lin-qing Xu Dan-tian Zhang Yong-chang Liu Bao-qun Ning Zhi-xia Qiao Ze-sheng Yan Hui-jun Li
文章页码：438 - 447
摘 要：Tempering is an important process for T/P92 ferritic heat-resistant steel from the viewpoint of microstructure control,as it facilitates the formation of final tempered martensite under serving conditions.In this study,we have gained deeper insights on the mechanism underlying the microstructural evolution during tempering treatment,including the precipitation of carbides and the coarsening of martensite laths,as systematically analyzed by optical microscopy,transmission electron microscopy,and high-resolution transmission electron microscopy.The chemical composition of the precipitates was analyzed using energy dispersive X-ray spectroscopy.Results indicate the formation of M3C（cementite） precipitates under normalized conditions.However,they tend to dissolve within a short time of tempering,owing to their low thermal stability.This phenomenon was substantiated by X-ray diffraction analysis.Besides,we could observe the precipitation of fine carbonitrides（MX） along the dislocations.The mechanism of carbon diffusion controlled growth of M23C6 can be expressed by the Zener’s equation.The movement of Y-junctions was determined to be the fundamental mechanism underlying the martensite lath coarsening process.Vickers hardness was estimated to determine their mechanical properties.Based on the comprehensive analysis of both the microstructural evolution and hardness variation,the process of tempering can be separated into three steps.
Lin-qing Xu1，Dan-tian Zhang1，Yong-chang Liu1，Bao-qun Ning1,2，Zhi-xia Qiao1,3，Ze-sheng Yan1，Hui-jun Li1
1. State Key Lab of Hydaulic Engineering Simulation and Safety,School of Material Science and Engineering,Tianjin University2. School of Materials Science and Engineering,Tianjin University of Technology3. School of Mechanical Engineering,Tianjin University of Commerce
摘 要：Tempering is an important process for T/P92 ferritic heat-resistant steel from the viewpoint of microstructure control,as it facilitates the formation of final tempered martensite under serving conditions.In this study,we have gained deeper insights on the mechanism underlying the microstructural evolution during tempering treatment,including the precipitation of carbides and the coarsening of martensite laths,as systematically analyzed by optical microscopy,transmission electron microscopy,and high-resolution transmission electron microscopy.The chemical composition of the precipitates was analyzed using energy dispersive X-ray spectroscopy.Results indicate the formation of M3C（cementite） precipitates under normalized conditions.However,they tend to dissolve within a short time of tempering,owing to their low thermal stability.This phenomenon was substantiated by X-ray diffraction analysis.Besides,we could observe the precipitation of fine carbonitrides（MX） along the dislocations.The mechanism of carbon diffusion controlled growth of M23C6 can be expressed by the Zener’s equation.The movement of Y-junctions was determined to be the fundamental mechanism underlying the martensite lath coarsening process.Vickers hardness was estimated to determine their mechanical properties.Based on the comprehensive analysis of both the microstructural evolution and hardness variation,the process of tempering can be separated into three steps.
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