Numerical and experimental analysis of welding parameters on residual stress in stainless steel 304L using ultrasonic methods

Residual stresses generated by the welding process have a significant impact on the structural performance and service life of components. In this study, the effects of welding speed and current on longitudinal residual stresses in AISI 304L austenitic stainless steel (SS 304L) were investigated using both experimental and numerical approaches. Residual stresses were measured at a depth of 1.5 mm using longitudinal critically refracted (Lcr) ultrasonic waves, and the acoustoelastic coefficients of the base metal and weld metal were determined through uniaxial tensile testing. Numerical simulations of the welding process were conducted using ABAQUS software.

The results showed that residual stresses in the weld metal region are tensile and gradually shift toward compressive values with increasing distance from the weld center. Increasing the welding speed reduced the magnitude of residual stresses, whereas increasing the current led to an increase in residual stress levels. A comparison between the numerical simulation and experimental ultrasonic measurements revealed an average discrepancy of 27 MPa in the weld metal region (equivalent to 15 %) and 10 MPa in the base metal region (equivalent to 12 %). The maximum observed difference between the numerical and experimental results was 40 MPa at the weld line and 39 MPa in the base metal. The findings of this study demonstrate the effectiveness of combining ultrasonic testing and finite element simulation in analyzing and optimizing welding parameters and predicting residual stress distributions.