MODELING OF THE DEFORMATION OF SHOT PEENED CYLINDRICAL SPECIMENS OF 42-CRMO-4 IN UNIAXIAL TENSION AND DEFORMATION AND OF THE RESULTING MACRO RESIDUAL-STRESSES

Tensile and compressive stress-strain-curves of shot peened and unpeen ed specimens of quenched and tempered 42 CrMo 4 (AISI 4140) with a dia meter of 5 mm only differ in the yield strengths and in the Luders-def ormation. In comparison to the core the regions close to the surface o f shot peened cylindrical specimens bear relatively large axial and ta ngential residual stresses and show different deformation properties. A multi-layer-model was developed to describe both the tensile as well as the compressive deformation behaviour of shot peened cylindrical s pecimens quantitatively. The calculated transitions from the elastic t o the elastic-plastic deformation state during tensile and compressive loading agree quite well with the experimental observations. Also the changes of axial and tangential macro residual stresses after distinc t tensile or compressive deformations are in best agreement with the m easurements.