MICRO-RESIDUAL-STRESS STATES IN SURFACE-L AYERS OF SHOT-PEENED 42-CRMO-4

The microstructure of the surface layer of normalized, martensitic har dened and quenched and tempered 42 CrMo 4 steel specimens was investig ated after equal shot-peening treatments, To characterize the micro-re sidual-stress states, the mean micro-strains, the domain size and the dislocation densities were determined with an X-ray one-line profile a nalysis. For micro-hardness values < 460 HV 0.3, the mean strains and the dislocation densities increase due to work-hardening processes. Ho wever, material states with micro hardness > 460 HV 0.3 reveal shot-pe ening-induced work-softening mainly caused by rearrangements of disloc ations.