STUDY OF THE EFFECT OF PLASTIC DEFORMATION ON THE CRYSTALLOGRAPHIC TEXTURE AND ACOUSTIC CHARACTERISTICS OF LOW-ALLOY STEEL

Abstract

he article presents the results of a study of the influence of plastic deformation on the change in the coefficients of the orientation distribution function (ODF) W400 and W420 of low-alloy steel 09G2S. To calculate the ODF coefficients, the velocities and times of propagation of shear and longitudinal bulk elastic waves and their ratios were used. The physical interpretation of the ODF coefficients W400 and W420 is given. The W420 coefficient depicts the effect of birefringence of shear bulk elastic waves, the W400 ratio is linearly related to Poisson's ratio. Both coefficients are structurally sensitive characteristics and are used to assess the state of materials by non-destructive testing methods. As a results of the study, it was found that the characteristic areas on the tension diagram: the yield area, the area corresponding to parabolic hardening, the beginning of neck formation, have a corresponding display on the dynamics of changes in the coefficients of the orientation distribution function. The yield area is characterized by an active change in the characteristics of the texture. Hardening leads to a decrease in the intensity of change in the coefficients of the orientation distribution function. Expressions are given that relate changes in Poisson's ratio to the value of hardening of the steel under study, the parameter of acoustic anisotropy with the value of plastic deformation. The calculated values of the hardening value according to the data of acoustic measurements are in good agreement with the hardening value obtained by analyzing the tensile diagram. The error in determining the magnitude of plastic deformation by the acoustic method was no more than 0.3%. It was found that monitoring the elastic characteristics by the acoustic method makes it possible to effectively assess the state of plastically deformed steel by a non-destructive testing method.