MARTENSITIC-TRANSFORMATION AND RESIDUAL-STRESSES AFTER THERMOMECHANICAL TREATMENT OF HEAT TREATABLE STEEL 42CRMO4 (SAE-4140)

The influence of thermomechanical deformation on the residual stresses caused by quenching in bar shaped specimens of heat treatable steel 4 2CrMo4 has been investigated using a mechanical method for determining the distribution of residual stresses of the first kind. The results obtained show that the residual stress distribution after quenching is affected by the strengthening and softening of the austenite as a res ult of deformation and recrystallization and the modified transformati on behaviour in martensite stage. An attempt is made to discuss qualit atively the influence of these changes on the generation of residual s tresses as compared to results obtained after conventional hardening.