夹杂物对高强钢焊缝金属组织和冷裂纹影响分析  

Effect of Inclusions on Microstructure of High Strength Steel Weld Metal and Formation of Cold Crack

作　　者：武丹[1,2] 刘政军 苏允海[1,2] 裘荣鹏 WU Dan;LIU Zhengjun;SU Yunhai;QIU Rongpeng(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China;School of Materials Science and Engineering,Shenyang Ligong University,Shenyang 110159,China)

机构地区：[1]沈阳工业大学材料科学与工程学院,辽宁沈阳110870 [2]沈阳理工大学材料科学与工程学院,辽宁沈阳110159

出　　处：《热加工工艺》2018年第23期246-249,共4页Hot Working Technology

摘　　要：采用自行研制的高强钢药芯焊丝对Q960钢进行了钨极氩弧焊焊接,在研究焊缝金属的组织和抗拉强度,以及25、0、-20和-60℃焊缝金属冲击功的基础上,分析了夹杂物的尺寸、形状和分布对焊缝金属组织中针状铁素体组织形成的影响,以及对焊缝金属冷裂纹形成和扩展的影响。结果表明:当焊缝金属中夹杂物尺寸在0.4~1.0μm之间时有利于针状铁素体形核,形核夹杂物为核壳结构,其核心为Mn、Ti和Al的氧化物,外壳为Mn的硫化物;焊缝金属中有形核夹杂物和非形核夹杂物两种;冷裂纹从非形核夹杂物处形成并向远处扩展,裂纹扩展中遇到形核夹杂物,其周围针状铁素体可阻碍其扩展,若遇非形核夹杂物则会产生二次裂纹。A self-developed flux cored wire for high strength steel was used to weld Q960 steel by tungsten argon arc welding.On the basis of studies of microstructure and tensile strength of weld metal and impact energy of weld metal at 25℃, 0℃,-20℃ and -60℃,the effect of size,shape and distribution of inclusions on acicular ferrite formation in weld metal and formation and propagation of weld metal cold crack were analyzed.The results show that the 0.4-1.0μm inclusions in weld metal are favorable to acicular ferrite nucleation.The nucleation inclusions are core shell structures,whose core is Mn,Ti and Al oxides,and the crust is Mn sulfide.There are effective nuclear inclusions and ineffective nuclear inclusions in weld metal. Cold crack forms around ineffective nuclear inclusions and extends far away.When cold crack encounters effective nuclear inclusions,the acicular ferrite around effective nuclear inclusions can hinder cold crack propagation.If the cold crack encounters ineffective nuclear inclusions,it will cause secondary cracks.

关 键 词：高强钢药芯焊丝 夹杂物 针状铁素体 冷裂纹 

分 类 号：TG401[金属学及工艺—焊接]