WB36钢多层焊接头近缝区网状组织研究(Ⅱ):显微结构及韧性  

Study on net-like microstructure in the heat affected zone of multilayer WB36 steel weldment (Ⅱ):microstructure and toughness

作　　者：王学[1] 常建伟 黄关政 任遥遥[3] 

机构地区：[1]武汉大学动力与机械学院,湖北武汉430072 [2]河南第一火电建设公司,河南平顶山467031 [3]武汉大学物理科学与技术学院,湖北武汉430072

出　　处：《材料热处理学报》2009年第2期76-80,共5页Transactions of Materials and Heat Treatment

摘　　要：研究了WB36钢临界再热粗晶区(IRCGHAZ)网状组织的构成、形成机理及对韧性的影响。结果表明,网状组织主要由颗粒状M-A组元和粒状贝氏体构成,其形成是由于一次粗晶区受到峰值温度在AC1～AC3的再次热循环作用时,晶界附近在加热过程中发生无序奥氏体转变,形成富碳的细小球形奥氏体,它们冷却时转变为粒状M-A组元和贝氏体。网状组织所在的IRCGHAZ韧性最低,但含有较多M-A组元的网状组织并不是导致IRCGHAZ脆化的主要原因,晶内板条件间形成的方向性排列的条状M-A组元直接导致了IRCGHAZ的脆化,这是由于条状M-A组元比颗粒状M-A组元更容易促进解理方式断裂。The net-like microstructure （NM） and its formation mechanism in the intercritically reheated coarse-grained heat（IRCGHAZ） of WB36 steel（15NiCuMoNb5） was investigated, and the influence of the microstrueture on toughness of the steel was examined. The results show that the NM is predominantly composed of granular M-A_ islands and hainite. During the secondary thermal eyele with an peak temperature between Ac1- Ac3, fine spherical austenite with high carbon content is formed at prior austenite grain boundaries of CGHAZ as a result of un-order α→γ transformation, and the austenite then transforms to granular M-A and bainite during cooling. The low CVN impact toughness of IRCGHAZ is mainly atrribtued to the lath M-A parallely distributed in the grain, but not related to the NM at prior austenite grain boundaries. This is owing to that lath M-A tends to cleavage fracture compared with granular M-A.

关 键 词：低合金高强钢 临界再热粗晶区(IRCGHAZ) 组织 脆化 M-A组元 

分 类 号：TG142.1[一般工业技术—材料科学与工程]