Welding of Low Carbon Steel Tubes Using Magnetically Impelled Arc Butt Welding: Experimental Investigation and Characterization

Abstract

Magnetically impelled arc butt (MIAB) welding is a solid-state technique of welding that utilizes the heating effect of a high-speed rotating arc for the formation of the weld. The process exhibits lower time and power consumption compared to conventional solid-state processes for tube–tube joining. However, the available research reports on MIAB welding of Mild Steel (MS)1018 are still inadequate and lack the details required for extending the applications of this process. Hence, this study was undertaken to investigate MIAB welding for MS 1018 tubes. Experimental investigations were performed on a specifically designed and newly fabricated MIAB welding machine. The experimental trials involved varying the process parameters and understanding their influence on joint strength and other weld characteristics. Microstructure of the MIAB weld consisted of acicular ferrite which differed from the microstructure of the heat-affected zone. These trials helped to arrive at the optimum parametric window that specified the ranges of key parameters viz. welding current, upset current, and welding time to yield an efficient weld. Chemical analysis of the weld indicated the absence of inter-metallics. MIAB welding of MS1018 showed greater strength and integrity at the joint when optimum ranges of the process parameters were maintained, and is feasible for deployment as economizer coils in boilers, pressure part tubes, and automobile tubular component joining applications.