METHOD TO DETERMINE RATIO OF PHASES IN STEEL Russian patent published in 2012 - IPC G01N3/42 

FIELD: measurement equipment.

SUBSTANCE: invention relates to the field of physical metallurgy, in particular, to methods for detection of phases ratio in ferrite-perlite steels. The invention concept is as follows: a smooth section of surface of an investigated steel sample is prepared. As a recommended force at an indenter, a force is accepted as produced as a result of microhardness definition in a reference sample made of steel, the grade of which corresponds to the steel grade of the investigated sample, and corresponding to a histogram of reference sample microhardness values, having express double-mode distribution. Measurements of microhardness are carried out at least in 50 random points of the prepared smooth section of the investigated sample surface and in steps at least three times: first with the recommended force to the indenter, then with the force higher and lower than recommended by 3-5 N. Histograms are built, which correspond to measurements of microhardness of the investigated sample at each step of measurements, and ratio of phases is determined in accordance with the histogram having double-mode distribution of microhardness of the investigated sample, by ratio of histogram areas corresponding to each phase. If double-mode distribution has several built histograms, then when defining the ratio of phases, measurement results are used, which are produced at the highest force at the indenter.

EFFECT: expansion of arsenal of methods for determination of phases ratio in steel with preservation of required accuracy and validity of parameters defined when executing the proposed method.

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