管线钢焊接局部脆化区的M-A组元  

M-A constituents in local brittle zones of pipeline steel

作　　者：孟凡刚[1] 陈玉华[2] 王勇[1] 

机构地区：[1]中国石油大学(华东)机电工程学院,山东东营257061 [2]南昌航空工业学院材料科学与工程学院,江西南昌330063

出　　处：《焊接技术》2007年第1期13-15,共3页Welding Technology

基　　金：中国石油大学(华东)博士创新基金项目(B2005-3);博士科研基金资助项目(Y040312)

摘　　要：采用焊接热模拟、金相分析及透射电镜研究了X70管线钢焊接局部脆化区M-A组元的形态、数量、分布及在透射电镜下的精细结构、形貌特征。结果表明,粗晶区M-A组元以块状为主,有少量呈长条状。再热临界粗晶区的M-A组元数量急剧增多,基本都是狭长的长条状,分布比较密集,M-A组元相邻间距较小,平均弦长较大,为4.21μm。透射电镜下条状M-A组元一般分布于贝氏体铁素体的板条界面处,块状M-A组元有的呈不规则形状,有的呈三角形。M-A组元中马氏体的精细结构为孪晶亚结构。The shape, amount, distribution and fine structure of M-A constituents in the local brittle zones of X70 pipeline steel were investigated by means of welding thermal simulation, metallographic analysis technology and transmission electron microscope (TEM). The results show that M-A constituents in coarse grained heat-affected zone are mostly massive and a small number is long banding. The volume fraction is 9.6% and the average length is 1.67 μm. The number of M-A constituents in intercritically reheated coarse grained heat-affected zone (IRCGHAZ) increases rapidly and the volume fraction is 18.58%. Most of the M-A constituents are long banding and distribute densely. The spacing interval between M-A constituents is small and the average length is 4.21 μm. Under TEM, long banding M-A constituents generally distribute between bainite ferrite laths, some of the massive M-A constituents are irregular shape and some are triangle. Fine structure of martensite in M-A constituents is twin sub structure.

关 键 词：X70管线钢 局部脆化区 M—A组元 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG457.6[金属学及工艺—金属材料]