MEASUREMENT AND CALCULATION OF RESIDUAL-STRESSES AFTER DIE FORGING

For die forgings, fabricated from steels Ck 45, 42 CrMo 4 and 38 MnSiV S 6 3, TTT and CCT diagrams were determined, and after different heat treatments, measurements of mechanical properties, fatigue strength a nd residual stresses were carried out. The diameter of the specimens a fter the forging process was 32 and 45mm. The residual stresses after quenching between -450 and +160N/mm(2) could be reduced to about 60N/m m(2) by tempering up to 620 degrees C. The fatigue strength in the ran ge of 300N/mm(2) depends more on the strength than on the residual str esses. Calculations with the program Antras-Thepla correlate well with the measured microstructures and residual stresses. This shows that t he materials and processing data used for the calculation are conform to real processes.