Probing joint strength and distortion in gas metal arc lap joining of aluminum and steel sheets

• Published in: Welding in the world Vol. 63; no. 2; pp. 229 - 236
• Main Authors: Goecke, Sven-F, Makwana, P., Shome, M., De, A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 08.03.2019; Springer Nature B.V
• Subjects: Aluminum; Arc heating; Chemistry and Materials Science; Distortion; Feed rate; Intermetallic compounds; Joining; Materials Science; Metal sheets; Metallic Materials; Research Paper; Solid Mechanics; Theoretical and Applied Mechanics; Thermal expansion; Thermophysical properties; Voltage pulses; Welded joints; Zinc coatings; Mixed-metal assembly; Gas metal arc joining; Zinc-coated steel; Thermal distortion; Aluminum alloy
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/s40194-018-0653-z

Joining of multi-metallic assemblies such as aluminum and steel sheets using fusion joining technologies is prudent although the formation of intermetallic compounds along joint interface has remained a critical challenge. An advanced, low-power input, gas metal arc process was employed here for joining of aluminum and zinc-coated steel sheets of dissimilar thicknesses in lap-joint configuration. The heat input during the process was restricted by fast responsive current and voltage pulses that allowed a synchronized arcing and short circuiting at a low arc power. The effect of heat input and thermophysical properties of base materials on the bead profile, joint strength, and distortion was studied extensively. The results indicated a rational improvement of joint quality with lowering of the heat input within a restrictive range of processing conditions such as wire feed rate and travel speed. Most importantly, the mixed-metal assembly exhibited different thermal distortions with the aluminum top sheet undergoing greater distortion than the bottom steel sheet due to a higher coefficient of thermal expansion.