METHOD OF ESTIMATION OF DILATOMETRIC STUDIES OF PHASE TRANSFORMATIONS IN IRON ALLOYS Russian patent published in 2017 - IPC G01N25/02 G01N33/20 

FIELD: measuring equipment.

SUBSTANCE: method includes the determination of critical points of phase transformations using a quenching dilatometer in which the sample is heated up at a constant rate, automatically recording the time from the beginning of the measurement, the temperature and the elongation of the sample under study during heating. Then, the dependences of the elongation of the sample on the temperature and the first derivative of the dilatogram on the sample temperature are constructed, a qualitative evaluation of the phase transformations is carried out with determination of the staging in the temperature range of the phase transformation by the presence of peaks. New is the fact that the first derivative of the dilatogram is decomposed into component peaks of the derivative using Gaussian curves with asymmetry, at the same time, the temperature limits of the phase transformation are determined at each stage, the temperature ranges of overlapping of several stages of the phase transformation are determined. Then the quantitative evaluation is performed, determining the volume ratio of phase transformation at each stage of total phase transformation during heating and/or cooling of the sample. According to the received data, the heat treatment mode is clarified in accordance with the specified or required sequence of phase transformations in the material under study in order to obtain a given structure and properties in products.

EFFECT: improving the quality of evaluation and information content of the dilatometric studies about the stages of phase transformations occurring in iron alloys when heated or cooled using a single quenching dilatometer, expansion of functional capabilities of the quenching dilatometer.

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