STUDY OF STRESS DEVELOPMENT IN AXISYMMETRICAL PRODUCTS PROCESSED BY RADIAL FORGING USING A 3-D NONLINEAR FINITE-ELEMENT METHOD

A hollow shafts popular axi-symmetric machine elements, are used frequ ently under severe service conditions such as for automobile transmiss ions, the shafts of aircraft, and turbine shafts. They are usually man ufactured through the radial-forging process. The residual stress in t hese forged products directly affects the material stability, the resi stance to deformation, the accuracy, and the fatigue life of products. In order to extend the operating life of products and satisfy the req uired quality of operation during customer usage, it is necessary to m onitor the residual stresses during the forging operations. As a way t o study residual stress formation due to radial forging, a three-dimen sional theoretical model uas developed using a non-linear finite-eleme nt method program. The workpiece used in the calculations was alloy st eel MILS 11595 and was assumed to have elasto-plastic behavior during forging. The Coulomb friction law was applied to simulate the contact behavior between the workpiece and the mandrel and between the workpie ce and the die. The residual stress distributions in the forged produc t were calculated and selected results were compared with published ex perimental data to verify the effectiveness of the developed model. (C ) 1998 Elsevier Science S.A.