Quantitative Evaluation of Thermally Induced Residual Sttresses in White Cast Iron and Steels with Different Cementite Morphologies

The starting point for this work were damages in rolls of chill casting. Results of damage analysis have shown that the reason for these damages were cracks caused by thermally induced residual stresses [1]. The reason for these microstructural residual stresses is a mismatch in the thermal expansion coefficients between the ferrite and cementite phases. It is well known that the thermal expansion coefficients of the ferrite and cementite phases are identical approaching the Curie-temperature of cementite (TC=210°C for pure Fe3C), whereas they are quite different at room temperature (Figure 1) [2,3]. Below the Curie-temperature the thermal expansion of cementite is smaller than that of the ferrite phase.