低碳贝氏体高强钢焊接工艺及冲击韧性研究  

Investigation on Welding Process and Impact Toughness of Low-carbon Bainite High Strength Steel

作　　者：刘朝霞 刘俊 孟羽 宁康康 许晓红 Liu Zhaoxia;Liu Jun;Meng Yu;Ning Kangkang;Xu Xiaohong(Research Institute,Jiangyin Xingcheng Special Steel Works Co.,Ltd.)

机构地区：[1]江阴兴澄特种钢铁有限公司研究院

出　　处：《宽厚板》2021年第2期11-14,共4页Wide and Heavy Plate

摘　　要：对Q690E低碳贝氏体高强钢进行80%CO_(2)+20%Ar混合气体保护焊接试验,并检测母材、焊接接头金相组织和力学性能,通过SEM手段观察母材和焊接接头冲击试样断口形貌。结果表明:Q690E钢母材冲击断口形貌表现为韧性断裂,焊接后热影响区(HAZ)冲击断口形貌表现为解理断裂;经过微观组织分析,HAZ冲击韧性下降,主要原因是HAZ区贝氏体组织中出现大量的M-A组元。HS-70焊丝低强匹配及熔合区贝氏体片层粗化导致焊接接头强度明显低于母材。80%CO_(2)+20%Ar mixed gas shielded welding test is performed on Q690E low-carbon bainite high strength steel,of which the microstructure of base metal and weld joint and the mechanical properties of weld joint are examined,the fracture morphology of impact specimens from base metal and weld joint is observed by means of SEM.The results show that the impact fracture morphology of base metal Q690E steel is characterized by ductile rupture,the impact fracture morphology of heat affected zone(HAZ)is characterized by cleavage rupture.By analyzing the microstructure,a quantity of M-A constituent presented in HAZ bainite is the major cause of decreased HAZ impact toughness after welding.Low strength matching of HS-70 welding wire and bainite coarsening of fusion zone lead to lower strength of weld joint than that of base metal.

关 键 词：低碳贝氏体高强钢 气体保护焊接 冲击韧性 焊接工艺 

分 类 号：TG457.11[金属学及工艺—焊接]