Microstructure and mechanical properties of low carbon medium-manganese (0.2C -7Mn) steel during ART annealing

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• 作者：WANG HuanrongLI ZigangWANG GuodongWANG WeiLIU Junliang
• 会议时间：2013-06-01
• 关键词：microstructure ; mechanical property ; retained austenite ; XRD ; SEM
• 作者单位：Research Institute , Baoshan Iron & Steel Co.,Ltd.,Shanghai 201900,China
• 母体文献：第五届宝钢学术年会论文集
• 会议名称：第五届宝钢学术年会
• 会议地点：上海
• 主办单位：中国金属学会
• 语种：chi

摘要

This paper deals with the effect of austenite reverted transformation ( ART) annealing time on microstructure and mechanical properties of low carbon medium manganese ( 0.2C - 7Mn) steel.It has been shown that the rod-like carbides precipitate intensively along the prior austenite grain and lath martensite boundaries with short time ART annealing at 630℃.With increasing the annealing time,the austenite nucleates between lath martensite and grows into coarsened grains.At the same time,the carbides in lath martensite dissolve gradually and the volume fraction of austenite increases correspondingly.A duplex microstructure consisting of ferrite and austenite was developed at prolonged ART annealing time up to 48h.The mechanical properties of 0.2C - 7Mn steel are closely related to the austenite volume fraction.The yield strength of the steel decreases with annealing time,which is attributed to the increased austenite volume fraction.In contrast,the tensile strength drastically decreases with short time annealing(<5 min) and then remains almost unchanged with long time annealing.The total elongation increases first before 6 h annealing and then slightly decreases at prolonged annealing time up to 48 h,which is related to the stability of austenite at room temperature.