Isothermal Microstructural Transformations of the Heat‐treatable Steel 42CrMo4 during Heat‐treatment following Hot‐forming

Apart from reducing the processing energy, hardening and tempering of near‐net shape forged components from their forging heat primarily promises shortened conventional process sequences with reduced manufacturing costs. In this case, the time‐temperature‐transformation diagrams (T‐T‐T diagrams) found in the literature can only be used to a limited extent for determining the microstructural transformations during the heat‐treatment. The reasons for this are that firstly, the deformation influences the transformation kinetics and secondly, the forming temperatures at which austenitising takes place are comparatively high. For this reason, isothermal deformation T‐T‐T diagrams for forging temperatures from 1200 °C and deformation levels of 0.3 and 0.7 were determined for the heat‐treatable steel 42CrMo4 (1.7225). These diagrams were subsequently modelled for simulating the heat‐treatment and implemented in the FE‐software ANSYS®.