CORRELATION OF ALMEN ARC HEIGHT WITH RESIDUAL-STRESSES IN SHOT PEENING PROCESS

The deformations of shot peened Almen strips constrained on Almen bloc ks with increasing shot peening time, and their subsequent changes aft er the fixing screws are removed, are experimentally investigated and modelled. Deflection of the constrained Almen strips appears, principa lly in the transverse direction, as soon as the first passes of peenin g are applied. The curvatures and the residual stress change with incr easing peening time. Removing the screws results in a significant defl ection and a great relaxation of residual stress in the longitudinal d irection only. A model is proposed to calculate the deformation and th e residual stresses in the constrained and free strips. A new problem arises in the evaluation and interpretation of the Almen intensity sca le.