Q890D钢激光-电弧复合焊冷裂纹敏感性  

Cold crack sensitivity of Q890D steel by laser-arc hybrid welding

作　　者：曹瑜琦 倪川皓 易伟 李建宇 Cao Yuqi;Ni Chuanhao;Yi Wei;Li Jianyu(National Engineering Technology Research Center of Concrete Machinery,Changsha 410013,Hunan,China;Zoomlion Heavy Industry Science&Technology Co.,Ltd.,Changsha 410013,Hunan,China)

机构地区：[1]国家混凝土机械工程技术研究中心,湖南长沙410013 [2]中联重科股份有限公司,湖南长沙410013

出　　处：《机械制造文摘（焊接分册）》2022年第2期1-6,共6页Welding Digest of Machinery Manufacturing

摘　　要：通过开展斜Y形坡口试验,研究了15 mm,20 mm两种板厚Q890D高强钢在室温和预热150℃条件下激光-电弧复合焊冷裂倾向。结果表明,在3.94 kJ/cm热输入下,15 mm厚Q890D钢预热150℃后焊接,无冷裂纹出现;不预热焊接,则会产生表面裂纹和根部裂纹;相同的热输入下20 mm厚Q890D钢预热150℃和不预热焊接,均会产生表面裂纹和根部裂纹。与不预热相比,采用焊前预热150℃,15 mm厚Q890D钢热影响区平均硬度从428 HV下降至418 HV;20 mm厚Q890D钢热影响区平均硬度从457 HV下降至444 HV。热影响区存在软化现象,在热影响区靠近母材一侧硬度比母材低,15 mm厚和20 mm厚Q890D钢软化区硬度降幅分别为6%和7%,二者基本相同。Q890D钢焊缝组织由马氏体组成,热影响区组织由回火索氏体和部分马氏体组成。与15 mm厚Q890D钢相比,20 mm厚Q890D钢的热影响区中更多的组织发生了发生马氏体转变。Through oblique Y-shaped groove test,cold crack sensitivity of Q890D high strength steel plates with thickness of 15 mm and 20 mm was studied by laser arc hybrid welding at room temperature and preheating 150℃.The results showed that at 3.94 kJ/cm heat input,there were no cold cracks in 15 mm thick Q890D steel after preheating at 150℃,while surface cracks and root cracks appeared without preheating.At the same heat input,there appeared surface cracks and root cracks in 20 mm thick Q890D steel at both room temperature and preheating 150℃.Compared with no preheating,average hardness of heat affected zone in 15 mm thick Q890D steel decreased from 428 HV to 418 HV by preheating 150℃before welding,and average hardness of heat affected zone in 20 mm thick Q890D steel decreased from 457 HV to 444 HV.It existed softening phenomenon in heat-affected zone,hardness on the side near heat-affected zone was lower than that of the base metal.Hardness of softening zone in Q890D steel with thickness of 15 mm and 20 mm was 6%and 7%respectively,which was basically the same.Microstructure of weld was composed of martensite,while microstructure of heat affected zone was made up of tempered sorbite and some martensite.Compared with Q890D steel with 15 mm thickness,more microstructure underwent martensitic transformation in heat affected zone of Q890D steel with 20 mm thickness.

关 键 词：Q890D 激光-电弧复合焊 斜Y形坡口 冷裂纹敏感性 

分 类 号：TG456.7[金属学及工艺—焊接]