镀锌层和焊接速度对镁/钢MIG焊接头微观组织的影响  

Effect of Zinc Coating and Welding Speed on Microstructure of Magnesium/Steel MIG Welded Joint

作　　者：冷宸 汪晓勇 彭红兵[1] 陈天威 LENG Chen;WANG Xiaoyong;PENG Hongbing;CHEN Tianwei(College of Metallurgy and Materials Engineering,Jiangsu University of Science and Technology,Suzhou 215699,China)

机构地区：[1]江苏科技大学冶金与材料工程学院,江苏苏州215699

出　　处：《热加工工艺》2024年第19期44-49,共6页Hot Working Technology

基　　金：江苏省自然科学基金青年项目(BK2020997);江苏省研究生科研与实践创新计划项目(KYCX21_3460)。

摘　　要：以MIG电弧作为热源,分别对AZ31镁合金/Q235低碳钢与AZ31镁合金/DX51D镀锌钢进行连接。通过改变焊接速度,研究其对AZ31/Q235、AZ31/DX51D焊接接头焊缝成形、微观组织及硬度分布的影响,并揭示镀锌层的影响机理。结果表明:当焊接速度分别为10、15 mm/s时,AZ31/Q235接头、AZ31/DX51D接头的焊缝成形较好。随着焊接速度的降低,AZ31/DX51D接头焊缝处析出更多的β-Al_(12)Mg_(17)相,界面层厚度增加。AZ31/DX51D接头界面结合较好,而AZ31/Q235接头界面出现未熔合、开裂等现象,这说明镀锌层有效促进了镁/钢界面的冶金结合。AZ31/DX51D接头界面处的硬度值最高达到250 HV,高于AZ31/Q235接头界面处硬度值。MIG arc was used as the heat source to connect AZ31 magnesium alloy/Q235 low carbon steel and AZ31 magnesium alloy/DX51D galvanized steel,respectively.By changing the welding speed,the influence of welding speed on the weld formation,microstructure and hardness distribution of AZ31/Q235 and AZ31/DX51D welded joints was studied,and the influence mechanism of zinc coating was revealed.The results show that,the weld for mation of AZ31/Q235 joint is bad.When the welding speed is 10,15 mm/s respectively,the weld formations of the AZ31/Q235 welded joint and AZ31/DX51D welded joint are good.With the decrease of welding speed,the precipitatedβ-Al_(12)Mg_(17) phase increases at the weld zone of AZ31/DX51D joint,and the interfacial layer thickness increases.The interfacial bonding of AZ31/DX51D joints is good,while the non-fusion,cracking phenomenons appear at the interface of AZ31/Q235 joints,which shows that the Zn coating effectively promotes the metallurgical bonding of Mg/steel interface.The maximum hardness of the interface of AZ31/DX51D joint reaches 250 HV,which is higher than that of the interface of AZ31/Q235 joint.

关 键 词：MIG熔-钎焊 镁/钢 焊接速度 硬度分布 

分 类 号：TG401[金属学及工艺—焊接]