Industrial practice often prescribes cleaning of steel surfaces prior to welding with shot blasting. Shot blasted components have been considered free of residual stresses. Hence, recent studies show that these residual stresses from mechanical surface treatments are not negligible. A simulation of the surface treatments and their mechanical effect in full scale though, is not possible under modern computational capabilities. Instead, a straightforward, pseudothermal approach is proposed and tested in the present study, in order to introduce an initial residual stress field from shot blasting by application of thermal strains. This engineering concept is applied for validation reasons on a small-scale specimen, where a measured profile of residual stresses from shot blasting is simulated with preciseness. Subsequently a component with dimensions of real weldments is modelled, so that simplifications reducing the computational time to acceptable levels can be derived.