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Control and Technological measurements
ArticleName New method to determine the true hardness of structural steels
DOI 10.17580/chm.2022.01.08
ArticleAuthor A. V. Udalov, A. A. Udalov

Vyatka State University, Kirov, Russia:

A. V. Udalov, Cand. Eng., Associate Professor, Dept. of Materials Science and Fundamentals of Design, e-mail:
A. A. Udalov, Senior Lecturer, Basic Dept. of Metallurgy, e-mail:


The hardness of the material hardened in the zone of penetration of the indenter is recorded by standard methods of measuring hardness. This disadvantage is the main reason for the appearance of the size effect (indentation size effect) and a decrease in the measurement accuracy. The aim of the work is to develop a mechanical method for determining the hardness of metals and alloys without taking into account hardening in the zone of penetration of the indenter. Based on the linear relationship between the hardness and the resistance to deformation of the material, a formula was obtained for determining the hardness without taking into account the effect of hardening in the indentation zone, which makes it possible to increase the accuracy of mechanical methods for determining the hardness, expands their functionality and scope. The essence of the proposed method is illustrated by the example of determining the hardness of specimens made of steel 20, subjected to compression at various degrees of deformation. Compression test method was used to construct a hardening curve, which was used to determine the resistance to deformation of the material in the zone of penetration of the indenter and then the hardness of the material without taking into account the hardening in the zone of penetration of the indenter. The developed method for measuring the hardness of metals and alloys makes it possible to increase the accuracy of mechanical methods, to avoid the influence of the indentation size effect on the final result, and can be used to optimize the technologies for manufacturing parts.

keywords Indenter, hardness, dimensional effect, degree of deformation, hardening, resistance to deformation, test load

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