大电流MAG焊不稳定熔滴过渡形成机理及影响因素分析  

Formation mechanism and influencing factors of unstable metal transfer in high current MAG welding

作　　者：杨文艳 樊丁[2] 张俊喜[1] YANG Wenyan;FAN Ding;ZHANG Junxi(Lanzhou Institute of Technology,730050,Lanzhou,China;Lanzhou University of Technology,730050,Lanzhou,China)

机构地区：[1]兰州工业学院,甘肃兰州730050 [2]兰州理工大学,甘肃兰州730050

出　　处：《焊接学报》2023年第11期110-116,I0009,共8页Transactions of The China Welding Institution

基　　金：甘肃省高等学校青年科技创新基金项目(2021KJ-17)。

摘　　要：熔滴过渡的稳定性对大电流熔化极活性气体保护焊(MAG)焊接质量至关重要.采用高速摄像系统、电信号采集系统对大电流MAG不稳定熔滴过渡过程、电弧形态及电信号进行研究,揭示不稳定熔滴过渡的形成机理,分析了影响大电流MAG不稳定熔滴过渡临界电流值的因素.结果表明,大电流MAG焊熔滴过渡为摆动过渡和混合过渡的不稳定过渡模式,液锥受强电磁力是失稳偏离焊丝轴向的直接原因,电弧旋转/摆动频率随熔滴过渡模式和电弧形态不同而不同.焊丝伸出长度为影响不稳定熔滴过渡临界电流值的主要因素,且在试验参数内随着焊丝伸出长度的增大临界电流值显著减小.The stability of droplet transfer is crucial for the quality of high current MAG welding.A high-speed camera system and electrical signal acquisition system were used to study the unstable droplet transfer process,arc morphology,and electrical signal of high current MAG.The formation mechanism of unstable droplet transfer was revealed,and the factors affecting the critical current value of unstable droplet transfer in high current MAG were analyzed.The results showed that the droplet transfer in high current MAG welding is an unstable transition mode consisting of swing and mixed transfer.The instability of the liquid cone due to strong electromagnetic force and deviation from the welding wire axis are the direct reasons.The arc rotation/swing frequency varies with the droplet transfer mode and arc shape.Dry elongation is the main factor affecting the critical current value of unstable droplet transfer,and the critical current value significantly decreases with the increase of dry elongation.Highlights:(1)In this paper,the conventional MAG welding machine is modified,the wire feeding speed is increased from 22 m/min to 50 m/min,and the welding current can reach 600 A.The unstable droplet transfer process,arc shape and electrical signal of high current MAG welding are studied.The formation mechanism of unstable droplet transfer is revealed,and the factors affecting the critical current value of high current unstable droplet transfer are analyzed.(2)The droplet transfer in high current MAG welding is an unstable transition mode characterized by swing and mixed transfer,and the instability of the liquid cone under the action of strong electromagnetic force deviates from the axis of the welding wire,which is the direct cause of the unstable transition;Dry elongation is the main factor affecting the critical current value of unstable droplet transfer.

关 键 词：大电流MAG 摆动过渡和混合过渡 形成机理 影响因素 

分 类 号：TG403[金属学及工艺—焊接]