焊接速度对高强镀锌钢板激光焊接头组织和性能的影响  

Effect of Welding Speed on Microstructure and Properties of Laser Welded Joints of High Strength Galvanized Steel

作　　者：蒋贤海[1] 谌小平[1] 

机构地区：[1]广东水利电力职业技术学院,广东广州510925

出　　处：《热加工工艺》2015年第15期185-187,共3页Hot Working Technology

基　　金：广东省教育科研规划课题(2013JK216)

摘　　要：采用激光焊接的方法对1.5 mm厚的DOGAL 800DP高强度镀锌钢板进行对接焊,通过用金相显微镜对接头显微组织进行观察,用万能拉伸试验机对接头抗拉强度及伸长率进行测试,研究了焊接速度对其焊接接头组织和力学性能的影响。结果表明,焊缝组织主要为贝氏体+少量的先共析铁素体及侧板条铁素体,热影响区组织主要为板条马氏体+贝氏体,马氏体含量明显高于焊缝;随着焊接速度提高,焊缝中铁素体含量减少,马氏体含量增加,热影响区组织细化,接头抗拉强度和伸长率均先升高后降低,当焊接速度为0.8 m/min时强度最高,1.0 m/min时伸长率最大;焊接速度高于1.2 m/min或低于0.6 m/min都不利于获得力学性能优良的焊接接头,当焊接速度为1.0 m/min时,接头具有最佳强塑性匹配。The laser welding method was used in the butt welding of 1.5mm thickness DOGAL 800 DP high strength galvanized steel, and the microstructure of the weld joints was observed by metallographic microscope. The tensile strength and elongation of weld joints were tested by universal material testing machine. The effect of welding speed on the microstructure and mechanical properties of laser welding joint was studied.The results show that the microstructure of welded joint consists of bainite and a small amount of proeutectoid ferrite and side-plate ferrite, the main microstructure of heat affected zone is lath martensite and bainite, and the martensite content is significantly higher than that in the weld seam.With the increase of welding speed, the ferrite content reduces and the martensite content increases in weld metal, the microstructure of heat affected zone refines, and both the tensile strength and elongation increases first and then decreases.The highest strength is obtained when the welding speed is 0.8 m min-1. The maximum elongation is obtained when the speed is 1.0 m min-1. The mechanical properties of the welded joints deteriorate when the welding speed is over 1.2 m·min-1or under0.6m·min-1, and the welded joints with optimum strength and plasticity can be obtained when the welding speed is 1.0m min-1.

关 键 词：激光焊 焊接速度 高强镀锌板 组织 性能 

分 类 号：TG456.7[金属学及工艺—焊接]