Magnetic and acoustic characteristics of steel 30CrMnSiA after rolling and pressing

Abstract

A group of magnetic and acoustic parameters of the cold-deformed 30CrMnSiA steel is determined. It has been revealed that the coercive force of this steel starts to decrease steadily at degrees of plastic deformation higher than 6%. A hypothesis is put forward on the relaxation of stresses of the first kind as a result of flat pressing after rolling of steel plates. To test the possibility of determining the degree of deformation of the 30CrMnSiA steel by ultrasound measurements, the propagation velocities of longitudinal, transverse, and Rayleigh waves are determined. The change in the velocity of longitudinal ultrasonic waves is 0.8% at deformation degrees ranging from 10 to 20%. The velocity of transverse and Rayleigh ultrasonic waves increases monotonically over the entire range of deformations, with a change in their velocity of 2.5% and 2.2% respectively. Thus, the most suitable parameter for determining the degree of deformation is the propagation velocity of transversal ultrasonic waves. © 2018 Author(s).