Thermal analysis of low alloy Cr-Mo steel

The paper deals with results of thermal analysis of low-alloyed chromium-molybdenum steel. The methods of analysis were dilatometry, differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The Ac-1 and Ac-3 temperatures of the steel samples measured by dilatometry and DTA during the heating period were in good agreement. Generated by cooling a martensitic structure first became apparent at 503 K. Tempering of the as-quenched samples showed the presence of the second tempering stage in the region between 473 and 573 K. At that stage heat capacity decreased from 0.48 to 0.32 J g(-1) K-1, as a result of conversion of transition carbide due to heat consumption. After normalization of the as-quenched samples the heat capacity values were restored to between 0.42 and 0.47 J g(-1) K-1 in the temperature range from 373 to 673 K.