Evaluation of Distortion and Residual Stresses in Dissimilar Metal Laser Welds

摘要

The distortion and residual stresses in laser weld joints play an important role in performing the intended functions. The objective of this research work is to evaluate distortion and residual stresses induced in dissimilar metal butt weld joints. The 304 L stainless steel and mild steel sheets of 0.98 mm thick are used in automobile industries. The laser welding experiments are conducted on dissimilar metals as per the L9 orthogonal array design matrix and optimal process parameters obtained using Artificial Neural Network. A mathematical model is proposed to estimate the angular distortion and longitudinal residual stresses in dissimilar weld joints. The longitudinal, transverse and twisting type distortions are evaluated using the Coordinate Measuring Machine, whereas residual stresses using an X-ray Diffractometer. The standard correction techniques are applied for background error correction and peak position was obtained using the Gaussian curve fitting technique. The outcome of the research work is useful for the evaluation of distortion and residual stress in dissimilar metal weld joints.