Study of phase transformation temperatures of alloys based on Fe–C–Cr in high-temperature area

Abstract

Three alloys based on Fe–C–Cr were studied. These alloys contained carbon in a range of 0.308–0.380 mass% and chromium 1.058–4.990 mass%. Temperatures of solidus (onward used as T_S), liquidus (onward used as T_L) and peritectic transformation (onward used as T_P) were studied in the high-temperature region. These temperatures were obtained using two thermal analysis methods: differential thermal analysis (onward used as DTA) and simple thermal analysis (onward used as TA). The Setaram Setsys 18_TM was used for experiments with employment of the DTA method. All measurements were taken in an inert atmosphere of pure argon at heating rate of 10 °C min⁻¹, and simple TA method was used for the experiments with the use of the Netzsch STA 449 F3 Jupiter. Measurements were taken in inert atmosphere of pure argon at a heating and cooling rate of 5 °C min⁻¹. Phase transformation temperatures were obtained by heating and cooling process and were approximated to “equilibrium conditions” (DTA method: zero heating rate and sample mass, standard, TA method: only standard) (Žaludová et al. in J Therm Anal Calorim 112:465–471, 2013a. doi:https://doi.org/10.1007/s10973-012-2847-8; J Therm Anal Calorim 111:1203–1210, 2013b. doi:https://doi.org/10.1007/s10973-012-2346-y). The experimental data were compared and discussed with the calculation results using IDS (solidification analysis package) software (onward used as SW) Thermo-Calc and the TCFE8 (Thermo-Calc Fe-based alloys) database. The results of the two alloys were compared with those published for similar steels. The experimentally obtained transition temperatures were close to the calculated values. The solidus, liquidus and peritectic transformation temperatures were lowered with increasing carbon (range 0.308–0.380 mass%) and chromium content (range 1.058–4.990 mass%). The smallest difference between the experimental results and theoretical calculations was observed at the liquidus temperature for all alloys. Nonetheless, the difference measured for the solidus temperatures was much greater.