Dependence of the Metal Hardness on the Degree of Plastic Strain in Different Deformation Procedures

Abstract

The results of experiments on measuring the hardness of the surface the underside (bottom) of the ball indentation are presented for several ball diameters and different loads of indentation in 8 plate specimens of steels and alloys. It is shown that when the degree of plastic deformation ε is expressed in the form of commonly used ratio of the diameters of the impress and indentation ball, the obtained dependencies of the hardness increment Δ HV = f(ε) disagree with the similar dependencies obtained upon rolling-induced deformation of the corresponding materials. At the same time, when ε is expressed as a ratio of the surface area of the indentation ( M) to the half surface area of the embedded ball ( M’) the determined dependencies match the dependences obtained upon rolling-induced deformation.