X80管线钢的过冷奥氏体转变规律和相变模型  

Transformation law of super-cooled austenite and phase transformation model of X80 pipeline steel

作　　者：谭会杰[1] 鲍小光 吴忠旺[1] 王海燕[1] Tan Huijie;Bao Xiaoguang;Wu Zhongwang;Wang Haiyan(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou Inner Mongolia 014010,China;Baogang(Group)Company Rail and Beam Factory,Baotou Inner Mongolia 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010 [2]包钢(集团)公司轨梁轧钢厂,内蒙古包头014010

出　　处：《金属热处理》2023年第7期61-65,共5页Heat Treatment of Metals

基　　金：内蒙古自治区科技攻关项目(2020GG0150)。

摘　　要：利用L78RITA淬火热膨胀仪研究了X80管线钢过冷奥氏体转变的相变规律,结合金相-硬度法绘制了试验钢的连续冷却转变(CCT)曲线。结果表明,随着冷却速率的增加,X80管线钢过冷奥氏体分别发生了铁素体、贝氏体、马氏体转变;冷速小于3℃/s时,组织为铁素体和贝氏体;冷速在3~20℃/s时,组织只有贝氏体;冷速大于40℃/s时,组织中开始出现马氏体,且随着冷速的进一步增大,马氏体的含量逐渐增多,贝氏体逐渐减少直至消失。试验钢硬度随着冷却速率的增加呈逐步升高的趋势。在CCT曲线基础上,建立了相变点温度-冷却速率关系模型,并通过回归计算得到拟合度较高的相变模型,且模型计算值与试验值之间能够很好的地吻合,证明了该相变模型的可行性。Phase transformation law of super-cooled austenite in X80 pipeline steel was studied by means of L78RITA dilatometer,and continuous cooling transformation curves of the tested steel were plotted combining with metallographic hardness method.The results show that with the increase of cooling rate,ferrite transformation,bainite transformation and martensite transformation occur in the super-cooled austenite of the X80 pipeline steel,respectively.When the cooling rate is less than 3 ℃/s,the microstructure is ferrite and bainite.When the cooling rate is 3-20 ℃/s,only bainite is found in the microstructure.When the cooling rate is higher than 40 ℃/s,martensite begins to appear,and with the further increase of the cooling rate,the content of martensite gradually increases,while the bainite gradually decreases and disappears.The hardness of the tested steel increases gradually with the increase of the cooling rate.Based on the CCT curves,the relationship model of phase transformation temperature-cooling rate is established,phase transformation model with high fit degree is gained by regression calculation,and the calculated value and test value are nearly similar that proves the feasibility of the phase transition model.

关 键 词：X80管线钢 连续冷却转变 冷却速率 相变模型 

分 类 号：TG142.1[一般工业技术—材料科学与工程]