Numerical and Experimental Investigation of Heat Distribution and Residual Stress Variation on Stacked Thin Sheets of CRNO Electrical Steel Post Tungsten Inert Gas and Cold Metal Transfer Welding

Abstract

The paper presents a numerical and experimental investigation on the stacking of thin, cold rolled nongrain-oriented (CRNO) electrical steel sheets post-tungsten inert gas (TIG) and cold metal transfer (CMT) welding for predicting the effects of TIG and CMT welding current on weld geometry, temperature field, and residual stress distribution in thin, stacked weld sheets. Numerical simulation of a transient nonlinear thermal three-dimensional (3D) element based on actual weld conditions was carried out using ansys software by employing a moving heat source model based on a 3D Gaussian distribution to predict changes in temperature. As a result of the thermal history provided by the model, a mechanical analysis is performed to determine the residual stress distribution and the surface distortion in the element. A significant increase in weld penetration and weld width of the samples was observed with the increase in welding current, as well as a change in the temperature field in the weld zone. Moreover, both the experimental and numerical data are consistent in their estimation of the generation of residual stresses in the weld samples. A numerical model is presented for predicting the thermomechanical behavior of TIG and CMT welded stacked CRNO structures in the stator core of electric motors.