Thermal Treatment Effect and Structural State of Rod-Shaped Assortment 40Kh Steel on the Speed of Ultrasound Waves and Poisson Coefficient

Propagation rates of ultrasound waves and Poisson coefficients in the rolled stock from 40Kh steel after various types and conditions of thermal treatment were studied. An unambiguous relationship of structural states and hardness with the rates of longitudinal, transversal, and Rayleigh waves and Poisson coefficients with the approximation coefficients of 0.83–0.99 was determined. The developed procedures of studies and special equipment, which implements a shadow–mirror technique of multiple reflections using contactless transmission and surface mount electromagnetic acoustic transducers, provide high exactness, reproducibility, and reliability of the acoustic structuroscopy methods.