Surface integrity of machined components. Residual stresses and fatigue

The first article on surface integrity which appeared in the February issue of the magazine described the deformation and microstructural changes which machining may induce in the surface of metal components. These changes may impair the surface properties and generally reduce the surface integrity of the finished component. In addition to the microstructural changes, residual stresses may also be generated at the surface. The formation of residual stresses and the effect of processing variables on them are described in this article. Remedies for thermal damage and methods of thermal damage/residual stress assessment are also considered.