RESESRCH OF THE KINETIC CHARACTERISTICS OF THE SOLID-STATE TRANSFORMATION OF Kh30N60M9 and Kh23N65M13 ALLOYS IN THE TEMPERATURE RANGE OF 500-650 °C, ACCORDING TO THERMOGRAVIMETRIC ANALYSIS

The results of the study of the structural states of single-phase alloys Kh30N60M9 and Kh23N65M13 for the conditions of heating samples at a rate of 1.0 °C/min are presented. The structural states of the alloy samples were obtained by water quenching; the alloy quenching temperature was 1107 and 1135 °C, respectively. The article presents the results of thermal analysis of samples of the considered alloys in the conditions of an inert gas - argon, without carrying out its additional purification from oxygen, the volume fraction of which was up to 0.003 %. As a characteristic of the structure state, an indicator of the rate of weight gain is proposed. According to the experimental results of weight gain, an original method for calculating this kinetic indicator as the rate of solid-state transformation, then the conversion coefficient (k) is proposed. The true values of weight gain considered are referred to the true values of temperatures in the temperature range of 500-650 °C, when the scales of variables and values of variables are proposed in the range of true values (0..1). As a result of the work, confirmation of the improved thermophysical characteristics for the Kh30N60M9 alloy in the considered temperature range was found, in comparison with the Kh23N65M13 alloy. The calculated indicators of the conversion coefficients of the alloy samples were confirmed by experimental data on the amount of enthalpy in the considered gradations of the temperature range, for which the areas under the DTA graphs of the Kh30N60M9 and Kh23N65M13 alloy samples were calculated for the conditions of heating the samples at a rate of 1.0 °C/min. It was found in the work that the decomposition of the solid solution structure is more inherent and essential for the structure of the Kh23N65M13 alloy in the temperature range of 500–650 °C.