Identification of distortion relevant-factors during austenitisation by the example of rings made from bearing steel 100Cr6

The identification of distortion relevant-factors in an overall process chain in order to describe the distortion behaviour of a regarded component is an important step in the method Distortion Engineering . In this context, the application of design of experiments (DoE) assures a systematic procedure during both experiment and distortion analysis. The distortion behaviour of the examined thin-walled bearing rings was characterised by harmonic analysis in explicit consideration of the direction of the respective shape changes. The change in roundness deviation due to heat treatment is controlled by a variation of the clamping system during machining. Based on the experimental results and additional finite element analysis, this effect is explained by local plastic deformation due to stress relief during heating of the non-uniform machining residual stress state. The variation of the supporting pattern during heat treatment induces a change in roundness and flatness deviation, respectively. The alteration in flatness deviation is also influenced by the heating rate. The distortion mechanism that is responsible for these effects could not be identified in this work. The experimental results provide an indication that creep processes during heat treatment could be an effect regarding distortion, whose importance should not be underestimated