摘要
针对双丝旁路耦合电弧熔化极气体保护焊(Gas metal arc welding,GMAW)主路、旁路熔滴过渡特性,采用静力平衡理论,分析主路、旁路熔滴表面所受到的作用力。发现双丝旁路耦合电弧GMAW焊接过程中,通过引入旁路电弧会引起主路电弧弧根面积的扩展,从而促进主路熔滴向熔池过渡;在采用纯氩气保护时,由于旁路焊炬为冷阴极并选择正极性接法即焊丝接负极,旁路电弧会自动爬升到焊丝固态区域的氧化膜上燃烧,导致电磁收缩力在旁路熔滴过渡过程中不起作用,旁路熔滴主要依靠重力克服表面张力向熔池过渡,因此旁路熔滴体积较大并且难以过渡。针对这一问题,提出向保护气体中添加氧元素来改善旁路熔滴过渡特性并进行焊接试验。当保护气体中的氧元素在旁路熔滴表面形成氧化膜后,旁路电弧会在旁路熔滴表面的氧化膜上稳定燃烧,此时电磁收缩力会作用在焊丝熔化区域并促进熔滴向熔池过渡。试验结果也表明,采用80%氩气+20%二氧化碳作为旁路保护气体时,焊接过程中旁路熔滴体积明显减小并且熔滴过渡频率明显加快,与理论分析一致。
The metal transfer behaviors in consumable double-electrode gas metal arc welding(GMAW) process is analyzed based on the state force balance theory. In main torch, the bypass arc enlarges the main arc root area to promote the main metal transfer; in bypass torch with direct current electrode negative, because the electromagnetic force does not work and only gravity promotes the metal transfer, the droplet is large and not easy to transfer. In order to improve the bypass metal transfer, a scheme is proposed which adds CO2 to shielding gas. By using this scheme, an oxide film will be formed at the bypass droplet and the bypass arc will bum on the bypass droplet. In this condition, the electromagnetic force will promote the bypass metal transfer. Then, the welding experiment is carded out to test the effectiveness of this scheme. The results show that, with 80%At and 20% CO2 as shielding gas, the size of bypass droplet is decreased and the frequency of bypass metal transfer is also increased obviously.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2013年第12期50-54,共5页
Journal of Mechanical Engineering
基金
国家自然科学基金(51165023)
陇原青年创新人才扶持计划
甘肃省高校基本科研业务费专项资助项目