Non-destructive evaluation of the yield stress for low carbon steel by ultrasound measurements

The non-destructive evaluation method for yield stress assessment in low carbon steels based on ultrasonic measurements of the longitudinal and transversal velocities and the longitudinal attenuation coefficient is proposed. First, the mean grain size $\bar D$ is calculated from the measured acoustic parameters and then the yield strength is estimated from these three parameters using the Hall-Petch relationship. Comparative non-destructive and destructive tests for yield stress evaluation are elaborated. The results obtained allow to be concluded that the accuracy of non-destructive evaluation of σ _y is reliable enough.