FUNCTIONAL TESTING OF THIN AND STACK WELDED M400-50 A5 CRNGO ELECTRICAL STEEL

Abstract

In this paper, the effect of gas tungsten arc (GTA) welding current on the mechanical–microstructural–magnetic (M[Formula: see text] properties of cold-rolled non-oriented electrical steel (CRNGO) are investigated. The thin CRNGO sheets of 0.5[Formula: see text]mm each are stacked, welded at a different range of welding current from 30 A to 110 A, and observed for mechanical testing (joint performance and micro-hardness), macroscopic (weld seam characterization), microscopic (grain size variation), and magnetic property evaluation of post-welded samples. The results showed that with the increase in weld current, significant variation in micro-hardness, weld strength, weld seam size, and grain size in the samples’ weld zone is observed. A massive increase in core loss and magnetic field strength, with a significant decrease in relative permeability, is observed for the welded samples compared to the non-welded sample. The samples’ weld strength was varying, depending on the size of the HAZ and fusion zone (FZ) region, for a different weld current range. The hardness in the samples’ weld region increases with the weld current, with relatively higher hardness values observed at the FZ region of weld. Besides, it is observed that the increase in weld current resulted in the formation of coarse-sized grains in the HAZ region of the weld sample, with fine grains existing at the FZ region for higher weld current. The study can be referred for determining the appropriate welding parameters for joining of stacked CRNGO sheets to achieve the desired material properties.