Abstract: In this paper,welding residual stresses and strains are analvsed for three types of weld on thick plate:the surface weld,the multi-repair weld and the multi-pass weld.A thermal clastic-plastic analysis technique is used under conditions of plane deformation.The results show that the triaxial residual stresses and plastic strains can accumulate to relatively high values just below the surface and at a short distance away from the weld area.As a consequence cold cracking may occur,causing the fracture toughness to deerease.More attention should be paid to this area in the manufacturing of thick walled structures.