STUDY OF THE INFLUENCE OF EXPERIMENTAL CONDITIONS ON THE TEMPERATURES OF PHASE TRANSFORMATIONS IN HIGH-TEMPERATURE AREA FOR Fe-C-Cr AND Fe-C-Ni BASED SYSTEMS

摘要

One model alloy based on Fe-C-Cr and one model alloy based on Fe-C-Ni were studied. Fe-C-Cr based alloy contained carbon of 0.34 wt. % and chromium of 0.92 wt. %. Fe-C-Ni based alloy contained carbon of 0.38 wt. % and nickel of 1.08 wt. %. Temperatures of phase transformations (temperature of the solidus, liquidus and peritectic transformation) were studied in the high-temperature area by a heating rate of 1, 2, 5, 10 and 20 °C/min., the influence of heating rate was investigated. The influence of the sample mass was also studied by the heating rate of 10 °C/min. Samples with mass 50, 100, 190, 280 and 370 mg were studied. Samples with the mass 190 mg were studied by various heating rates. The Setaram Setsys 18? device was used for experiments with the use of the DTA method. No influence of the heating rate was detected for the temperature of solidus for both alloys. The most significant influence of heating rate was observed for the temperature of liquidus (temperature difference 6-8 °C). More noticeable impact of heating rate on the temperature of peritectic transformation shift was observed by Fe-C-Cr based alloy investigation. The influence of sample mass is negligible regarding the temperature of solidus and significant in case of liquids (for both alloys) and peritectic transformation (for Fe-C-Cr alloy) temperature.