Hardness – volumetric characteristic of material

Abstract

Producing details for different purposes is guided by the conditions of their work and, therefore, attention is paid to such characteristics as strength, viscosity and hardness. Only the method of determining the hardness of the material allows you to conduct research without destroying the detail in addition to physical methods. This takes into account the fact that the other properties are indirectly related to the hardness parameter. The main disadvantage of all modern methods of the material hardness measurement is the inconsistency of the practical content of the units of measurement of the studied parameter to the theoretical essence of hardness - as a physical quantity that characterizes the properties of a rigid body. The units of all hardness measurement methods, depending on the scale factor, are usually compared by converting their values to such generally accepted methods as Brinell, Rockwell, or Vickers. The conversion of the hardness values obtained by different methods should be used very carefully and preferably for a preliminary assessment of the relative changes in material properties. When applying these methods, the units of measurement are the ratio between the load on the indenter, a given standardized shape and the area or depth of the imprint. However, based on the physical content of a property such as hardness, it is necessary to determine the relationship between the load on the indenter and the volume of the displaced material. This work aims to establish a theoretical basis for the digital characteristics of units of hardness obtained by different measurement methods. To provide the physical meaning of the determining of hardness, the dependence of the volume of the displaced material on the applied load was determined. The comparison of these values made it possible to really determine the relationship between the units of different methods not based on practical comparisons, but by summing up the theoretical basis. The obtained results indicate a sufficiently high correlation between the results obtained with different hardness measurement methods.