Due to the process-specific high material utilization and the associated high energy and resource efficiency, cold forming processes represent an important technology in the processing of steel. To increase wear resistance and fatigue strength, cold formed workpieces are often case hardened. However, case hardening is an energy- and cost-intensive process step. As a complement, the finishing may be realized by means of mechanical surface treatments, like deep rolling, machine hammer peening or shot peening. These treatments improve the surface layer condition of the component by inducing favorable residual compressive stresses, strain hardening, grain refinement and surface smoothing to increase wear resistance and fatigue strength.
For the design of the surface treatment process of an impact extruded component, there is a considerable deficit in scientific knowledge about the concrete cause-effect relations between process parameters and surface integrity as well as component performance. To make these interactions explainable, knowledge about internal stress and temperature distributions during process execution is necessary. These can only be determined numerically. For this reason, the finite element method is a suitable tool for an overall investigation of the processes.
In the present work, a manufacturing process consisting of full forward extrusion and deep rolling is implemented as finite element model. The focus of this model is a fully coupled thermal-stress analysis.
The investigations are carried out for the material 16MnCr5. This case-hardening steel is used to produce workpieces via cold forming, which are used in both hardened and unhardened condition. The experimental performance of the simulations performed here has already been carried out for this material.
