Assessing the Influence of Different Forging Process Parameters on the Local Fatigue Properties of a Precipitation Hardening Ferritic-Pearlitic Steel

摘要

The use of precipitation hardening ferritic-pearlitic steels for forged components opens up huge potential for the reduction of CO_2 emissions and production costs by avoiding additional heat treatment. The material properties are calibrated by a defined cooling process, which utilizes the forging heat still stored in the component. Related to the sensitivity of the material properties to the deformation and temperature gradient, the influence of process parameters on the local properties has to be assessed experimentally by fatigue testing with small scale specimens. With respect to an improved and physically sound numerical modelling of the local strain response to the external load-time function for the fatigue assessment of components, the local property distributions have to be examined with specimens manufactured either by a process simulation of the forging and the consecutive cooling process or extracted existing components made from identical material. Based on the results of the fatigue testing for specimens with defined logarithmic strain and cooling gradient, a local stress-strain behavior and fatigue properties can be assigned during the numerical evaluation of the local strain response to an external load-time function.