EMS-CO₂ Welding: A New Approach to Improve Droplet Transfer Characteristics and Welding Formation

Abstract

In this article, to improve the stability of droplet transfer and reduce the spatter of pure carbon dioxide gas shield welding (CO₂ welding), we propose a new welding method called EMS-CO₂ welding by applying an additional longitudinal electromagnetic field to a CO₂ welding process (abbr. EMS-CO₂ welding). The characteristics of droplet transfer, welding formation and microstructure between EMS-CO₂ welding and general CO₂ welding on a Q235 low carbon steel plate are studied. The results show that EMS-CO₂ welding improves droplet transfer process, increases the stability of droplet transfer, and delivers better control of the welding spatter. Meanwhile, EMS-CO₂ welding generates welding formation with refined grains, welding seams with uniform microstructure, and welding joints with a higher quality. Therefore, EMS-CO₂ welding stands for the state of the art in short-circuit transfer CO₂ welding especially.

Keywords:

• Droplet
• Magnetic
• Microstructure
• Stability
• Transfer
• Welding

ACKNOWLEDGMENTS

The authors gratefully acknowledge the support of the Ph.D. Programs Foundation of Ministry of Education of China (No. 20070611030), Natural Science Foundation Project of CQ CSTC (No. 2008BB3303 and 2009BA3026), the Program for New Century Excellent Talents in University (NCET-08-0607), CHANGJIANG Scholars and Innovative Research Team in University (IRT 0763), the project of the State Key Laboratory of Mechanical Transmission in Chongqing University, China. The authors are very grateful to Dr. Qingzhong Liu of the New Mexico Institute of Mining and Technology for his suggestions and generous supports, and to Ms. Elisa Glaser and Mr. Keegan Livoti of the Writing Center of the New Mexico Tech for their professional and generous editing help.