Reduction of welding residual stresses and distortion

Abstract

Welding residual stresses have a negative or positive effect on the strength of the component depending on their type, sign, direction and distribution. Triaxial tensile residual stresses in combination with cracklike defects promote brittle fracture. Uniaxial or biaxial tensile residual stresses diminish corrosion resistance and enhance the stability limit; compressive residual stresses improve the fatigue strength. Details of this are provided in Chapter 5 and in Ref. [437] (ibid., Sections 2.3.2 and 3.4). Components with welding residual stresses may distort during subsequent machining, storage and service loading. A particularly disturbing effect is the back-spring deformation during metal cutting. Welding distortion reduces the fatigue strength and limit load of the components. Specified manufacturing tolerances may be exceeded as a result of welding distortion. It is therefore necessary to minimize welding residual stresses and welding distortion or, as far as possible, to control them according to the respective requirements.