1. 1) J. Y. Wang, Y. S. Ren, F. Yang and H. B. Guo: Sci. Technol. Weld. Join., 12 (2007), 505.
2. 2) N. Guo, M. R. Wang, W. Guo, J. B. Yu and J. C. Feng: Sci. Technol. Weld. Join., 19 (2014), 385.
3. 3) W. Li, K. Gao, J. Wu, J. Wang and Y. Ji: Int. J. Adv. Manuf. Technol., 78 (2015), 573.
4. 4) Y. H. Kang and S. J. Na: Weld. J., 82 (2003), 93s.
5. 5) J. Y. Wang, F. Yang, W. Han and W. H. Li: Swing arc narrow gap GMA welding method and its torch, China Patent 200810236274.5, (2008).