Investigation on droplet momentum in VPPA-GMAW hybrid welding of aluminum alloys
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- 作者：Haitao Hong ; Yongquan Han ; Maohua Du…
- 关键词：Variable polarity plasma arc ; gas metal arc welding ; Droplet momentum ; Droplet transfer ; T test ; Aluminum alloys
- 刊名：The International Journal of Advanced Manufacturing Technology
- 出版年：2016
- 出版时间：September 2016
- 年：2016
- 卷：86
- 期：5-8
- 页码：2301-2308
- 全文大小：1,423 KB
- 刊物类别：Engineering
- 刊物主题：Industrial and Production Engineering
Production and Logistics
Mechanical Engineering
Computer-Aided Engineering and Design - 出版者：Springer London
- ISSN：1433-3015
- 卷排序：86
文摘
Variable polarity plasma arc-gas metal arc welding (VPPA-GMAW) is a superior technology for welding thick plates of high-strength aluminum alloys. It integrates the advantages of energy focusing and high penetration depth in VPPA welding, and those of high welding efficiency and wide range of technological parameters in GMAW process. In this work, we investigated the droplet momentum in paraxial VPPA-GMAW hybrid welding of 7A52 aluminum alloys, and the technological parameters of welding process was also optimized. The images of droplet transfer were captured by high-speed camera, while the droplet speeds and sizes were statistically analyzed by t tests of independent samples. The results showed that the speeds of droplet arriving at the weld pool were significantly between GMAW and VPPA-GMAW processes, and the droplet speed increases with increasing plasma currents within a certain range. Meanwhile, the droplet momentum in VPPA-GMAW process is larger than that in conventional GMAW process. We also found that as the droplet momentum increased, the depression of weld pool grew more obvious and greatly facilitated the deep-penetration welding. In VPPA-GMAW process, it became more and more easier for the droplet to fall off the wire when the electromagnetic force gradually increased during pulse period. Droplet movement through the arc zone was further accelerated since the central pressure of arc column increased during base period. This research can provide some theoretical support for thick plate welding of high-strength aluminum alloys and help for deeper understanding of the hybrid arc coupling mechanism.