不预热焊接工艺焊接X70管线钢接头的组织与性能  

Microstructure and Properties of X70 Pipeline Steel Joints Welded by Welding Process without Preheating

作　　者：张德芬[1] 李曾珍[1] 罗红松 王同举 

机构地区：[1]西南石油大学材料科学与工程学院,成都610500 [2]中国石油天然气管道局第一工程分公司,廊坊065000

出　　处：《机械工程材料》2014年第12期37-41,96,共6页Materials For Mechanical Engineering

基　　金：四川省高等学校油气田材料重点实验室资助项目(12YQT025)

摘　　要：分别采用焊前预热和不预热的两种焊接工艺对X70管线钢进行焊接,采用光学显微镜、拉伸试验机和冲击试验机研究了焊接接头的显微组织、拉伸性能和冲击性能。结果表明:焊前预热接头的组织多为细小的针状铁素体、多边形铁素体等,而不预热接头的组织中晶粒明显长大,出现粗大粒状贝氏体和少量马氏体;焊前预热的焊接接头其抗拉强度和冲击韧性较不预热的好些,但不预热焊接工艺焊接的接头仍能满足性能要求;考虑工程到建设成本方面,不预热的焊接工艺可用于X70钢焊接。X70pipeline steel was welded using two welding processes with preheating and without preheating before welding,respectively.The microstructure,tensile property and impact property of welded joints were studied by optical microscopy,tensile testing and impact testing.The results show that the microstructure of the joint with preheating before welding consisted of small acicular ferrites and polygonal ferrites.The grains of the joint without preheating grew up significantly,coarse granular bainites and a small amount of martensites could be found in its microstructure.The joint with preheating had the better tensile strength and impact toughness,compared to that without preheating.But the properties of the joint without preheating still met requirements.Considering the engineering economic costs,the process without preheating can be used in the welding of X70 steel.

关 键 词：X70管线钢 不预热焊接工艺 组织 性能 

分 类 号：TG457.6[金属学及工艺—焊接]