Intelligent Welding System for Automobile Components to Optimize Angular Distortion and Longitudinal Residual Stresses

Due to alternate local heating and cooling (Thermal cycles) during welding, complex stresses occur and so residual stresses and angular distortion occur after welding. The residual stresses and angular distortion present in the welded components cause internal cracks and mismatching of welded automobile structures. Also the tensile residual stresses in area near the weldment may cause fractures under certain conditions whereas compressive residual stresses in the base plate may reduce buckling strength of structural members. Hence a welding system which is capable of predicting and acting according to it is the need of the hour.

It is difficult to obtain a more reliable complete analytical solution to predict angular distortion and maximum residual stresses for a wide range of welding processes, materials and process parameters. Hence in this investigation, the statistical method of five level factorial central composite rotatable experimental design has been used to develop mathematical models to correlate angular distortion and maximum longitudinal residual stress with process parameters for multi-pass gas metal arc welding (GMAW) of structural steel. Further, these mathematical models help to optimize GMAW process and to make it a cost effective one by minimizing the weld defects due to angular distortion and residual stresses.