Study on notch tensile properties of Magnetically Impelled Arc Butt (MIAB) welded carbon steel tubes

Abstract

Magnetically Impelled Arc Butt (MIAB) welding is a pressure welding process that uses the circumferential rotating arc to cause uniform heating of the faying surfaces. In this work, notched tensile testing of MIAB welded Carbon steel was carried out to determine the notch sensitivity of Thermo-Mechanically Affected Zones (TMAZ) and to compare the notch tensile property of these zones with the base metal property. In MIAB welding, after sufficient melting of the faying surface, a short pulse of high current is applied to expel the molten metal and impurities from the interface before welding. Insufficient expulsion and formation of Light Band (LB) zone at weld interface resulted in lower Notch Tensile Strength (NTS). Incomplete expulsion with lower upset current at the weld interface contributes to lower Normalized Notch Strength Ratio. Instead higher upset current contributed to higher NTS due to complete expulsion and stronger acicular ferrite formation. Other TMAZs away from the weld interface showed higher notch tensile strength with Notch Strength Ratio (NSR) and Normalized Notch Tensile Strength Ratio (NTSN) greater than unity.