A novel approach for interpreting the solidification behaviour of peritectic steels by combining CSLM and DSC

Solidification and phase transformations in two commercial low‑carbon peritectic and non-peritectic steels are analysed in-situ through the combination of Differential Scanning Calorimetry (DSC) and Confocal Scanning Laser Microscopy (CSLM), as well as thermodynamic calculations using Thermo-Calc. Conventional peritectic transformation is clearly documented in the peritectic steel upon heating using DSC, however, upon cooling, the peritectic nature of the steel is less apparent. CSLM has highlighted that what was previously reported to be an undercooled peritectic reaction, is in fact the bulk transformation of the solute poor dendrite cores from delta-Fe (δ) to austenite (γ). It has been shown that combining the detailed temperature data in samples obtained by DSC with CSLM observations of microstructure evolution facilitates the interpretation of phase transformation in peritectic steels.