METHOD OF TEMPERATURES DETERMINATION OF PHASE TRANSFORMATIONS IN METALS Russian patent published in 2015 - IPC G01N25/02 

FIELD: metallurgy.

SUBSTANCE: sample is tested using single hardening dilatometer and inertia-free thermocouple welded to the sample. Sample is heated with continuous speed using the inductor. Time from measurement beginning, temperature of sample, sample absolute elongation and relative power of the inductor are automatically recorded. For the phase transformations of 1 type based on the sample test results on the same coordinate field the relationships W = f(T_sample) are plotted, where W is relative power of the inductor, %, T_sample is sample temperature, °C. As per the plots the first derivative of the relative power of the inductor is determined in each point. Then on the same coordinate field the relationships of absolute elongation vs. sample temperature Δl = f(T_sample) and first derivative of relative power of inductor vs. sample temperature dW/dT_sample = f(T_sample) are plotted. Beginning and end of phase transformations of 1 type are determined as critical points (T_b) and (T_e) as per moment of function dW/dT_sample. = f(T_sample) separation from zero level on the background of function Δl = f(T_sample) change. Temperature of phase transformation of type 2 is determined as critical point (T_cr) as per position of peak of first derivative of the relative power of the inductor.

EFFECT: increased accuracy of determination of beginning and end of the phase transformations of types 1 and 2 in the studied metal.

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