焊接热输入对X70级管线钢埋弧焊接头热影响区组织的影响  

Effect of Heat Input on Microstructure of Heat Affected Zone in Submerged Arc Welded Joints of X70 Pipeline Steel

作　　者：杨津瑜 

机构地区：[1]中油管道机械制造有限公司,河北廊坊065000

出　　处：《热加工工艺》2014年第13期164-166,共3页Hot Working Technology

摘　　要：采用埋弧焊焊接X70级管线钢。采用OLYCIA m3软件对热影响区的晶粒度进行评级,采用OLYMPUS-PMG3光学显微镜对热影响区进行显微组织观察。结果表明,经过焊接热作用后,母材中原始的针状铁素体组织和少量的珠光体组织转变为粗大的粒状贝氏体组织。X70级管线钢为细晶粒钢,受焊接高温热作用后,其晶粒具有长大倾向。焊接过程中,热输入越高,晶粒长大倾向越严重。焊接热输入为30.6 kJ/cm时,其过热区粒状贝氏体组织的晶粒尺寸为热输入19.04 kJ/cm条件下粒状贝氏体晶粒尺寸的1.2倍。X70 pipeline steel was welded by submerged arc welding. The grain size of bainite in the heat affected zone was evaluated with OLYCIA m3 software. The microstructure of heat affected zone was investigated by OLYMPUS-PMG3 optical microscope. The results show that the original acicular ferrite and perlite structure in the base metal transforms to coarse grain bainite structure after welding. X70 pipeline steel is a kind of steel with fine grain structure, and the microstructure has a tendency of coarsening under the effect of high temperature. During welding, with heat input increasing, the microstructure became coarsening. The grain size of grain bainite under the condition of high heat input with 30.6 kJ/cm is almost 1.2 times higher than that of grain bainite under the condition of lower input with 19.04 kJ/cm.

关 键 词：X70管线钢 埋弧焊 热影响区 显微组织 

分 类 号：TG445[金属学及工艺—焊接]