MEASUREMENT OF DEEP-ROLLING RESIDUAL STRE SS-DISTRIBUTIONS ON COMPONENTS

In many practical cases surface layers of components are the most heav ily stressed material zones. In order to improve the fatigue strength and the wearability of components thermal, thermochemical and mechanic al surface treatment methods like induction hardening, case hardening, nitriding, shot peening and deep-rolling are applied for several year s. The effect of these methods depends on the increase of strength and on the production of compressive residual stresses in the heavily str essed surface layers. The mechanical processes also affect the surface roughness which may be reduced by choosing suitable process parameter s. Due to the mechanical surface treatment by deep-rolling fatigue str ength improvements up to 200% are possible [1], and the compensation o f the notch effect was observed for notched specimen [2]. In the indus try the deep-rolling is applied on e.g. crankshafts, screws, valve sha fts and actuation shafts. The direct control of surface layer properti es, like residual stresses and hardening, by x-ray measurements on axi al sections of the components is presented here as a method for qualit y insurance of rolled parts. The measuring method may also be used to verify results of FEM-simulations. FEM-simulations are applied to esti mate the modification of the residual stresses due to preparation.