陡坡X70管线钢热丝TIG焊接头组织和性能  

Microstructure and properties of X70 pipeline steel welded joints with hot-wire TIG welding process at steep slope

作　　者：李立英 盛学臻 高彦伟 刘乐 韩彬 LI Liying;SHENG Xuezhen;GAO Yanwei;LIU Le;HAN Bin(School of Materials Science and Engineering in China University of Petroleum(East China),Qingdao 266580,China;PetroChina(Xinjiang)Petroleum Engineering Company Limited,Karamay 834000,China)

机构地区：[1]中国石油大学(华东)材料科学与工程学院,山东青岛266580 [2]中油(新疆)石油工程有限公司,新疆克拉玛依834000

出　　处：《中国石油大学学报（自然科学版）》2024年第6期226-233,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家重点研发项目(2021YFA1000103);山东省重点研发项目(2020CXGC010207,2022CXGC010202);中国石油工程建设有限公司科研项目(CPECC2020KJ09)。

摘　　要：采用两种不同的热输入对陡坡25°X70管线钢进行热丝TIG焊,采用光学显微镜和电子显微镜对接头组织进行观察,并测试接头的拉伸、弯曲、硬度以及冲击韧性,分析两种焊接参数的适应性以及坡度对接头组织和力学性能的影响。结果表明,热输入对接头组织类型影响不大,但影响晶粒大小,坡度影响盖面焊粗晶区宽度以及晶粒大小,下坡口粗晶区宽度以及晶粒大小均大于上坡口;大热输入接头各项力学性能均合格,小热输入盖面焊趾硬度较高,导致弯曲开裂,上下坡口热影响区冲击功差别不大;建议实际工程中使用焊接效率高且接头质量好的大热输入参数。The hot-wire TIG welding process was used to weld the 25°X70 pipeline steel with two different heat inputs.In order to analyze the adaptability of the two welding parameters and the influence of slope on the microstructures and mechanical properties of welded joints,the microstructures of welded joints were observed with an optical microscope(OM)and a scanning electron microscope(SEM).Meanwhile,the mechanical properties of welded joints such as tension,bending,hardness and impact toughness were measured.The results show that the heat input has little effect on the microstructure type of welded joints,but affects the grain size.The slope affects the width and the grain size in the coarse-grained heat-affected zone(CGHAZ)of the cover weld.The width and the grain size in CGHAZ of the lower groove are both bigger than those of the upper groove.The mechanical properties of welded joint with a high heat input are qualified.However,the hardness of the cover weld toe with a low heat input is high,leading to cracking of bending specimens.The HAZ impact energy at both of the upper and the lower slopes does not differ much.It is suggested that welding parameters with a high heat input,which has a high welding efficiency and a good joint quality,should be used in practical projects.

关 键 词：热丝TIG焊 陡坡 X70管线钢 显微组织 力学性能 

分 类 号：TG442[金属学及工艺—焊接]