Effects of welding wire composition and welding process on the weld metal toughness of submerged arc welded pipeline steel

De-liang Ren1,2) ,Fu-ren Xiao1) ,Peng Tian3) ,Xu Wang3) ,and Bo Liao1) 1) Key Lab of Metastable Materials Science & Technology and College of Materials Science & Engineering,Yanshan University,Qinhuangdao 066004,China 2) Department of Materials Science and Engineering,Shijiazhuang Railway Institute,Shijiazhuang 050043,China 3) Steel Pipe Works of North China Petroleum,Qing County 062658,China

摘 要：The effects of alloying elements in welding wires and submerged arc welding process on the microstructures and low-temperature impact toughness of weld metals have been investigated. The results indicate that the optimal contents of alloying elements in welding wires can improve the low-temperature impact toughness of weld metals because the proeutectoid ferrite and bainite formations can be suppressed,and the fraction of acicular ferrite increases. However,the contents of alloying elements need to vary along with the welding heat input. With the increase in welding heat input,the contents of alloying elements in welding wires need to be increased accordingly. The microstructures mainly consisting of acicular ferrite can be obtained in weld metals after four-wire submerged arc welding using the wires with a low carbon content and appropriate contents of Mn,Mo,Ti-B,Cu,Ni,and RE,resulting in the high low-temperature impact toughness of weld metals.

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