Effect of Hot Rolling Process on Microstructure and Residual Stress of Stainless Steel Clad Plate Weld

The influence of hot rolling process on the microstructure and residual stress of 304 stainless steel welds was investigated using a rolling vacuum composite plate, with rolling reduction ratios set at 0%, 10%, 20%, 30%, and 30%/20%. The results show that, as the rolling reduction ratio increases, the grain distribution becomes progressively uniform, and the average grain size diminishes from 150.3 μm to 77.9 μm; a portion of high-angle grain boundaries transforms into low-angle grain boundaries（LAGB）, with the proportion of LAGB rising from 62.0% to 89.6%; these LAGB impede dislocation movement, causing dislocations to accumulate at the LAGB, and the density of geometrically necessary dislocations increases from 1.32×10¹³m^-2to 3.61×10¹³m^-2; the increased dislocation density leads to greater lattice distortion within the material,altering its internal stress state, resulting a stress transition from residual tensile stress of 23.7 MPa to residual compressive stress of 114.3 MPa.