Effect of Grain Size of Steel on Ultrasonic Longitudinal Wave Velocity to Shear Wave Velocity Ratio

Determination of the grain size is usually done by microscopic techniques which require special sample preparations. Nondestructive evaluation of grain size becomes important when sample preparation is restricted such as on a finished product. Nondestructive evaluation of grain size could be done through ultrasonic attenuation measurements. However, in such instances the dimensions of the components need to be known. As such, this work focuses on determining the grain size nondestructively when the material thickness is unknown. Hence, this paper presents a method to determine the grain size of a metal through ultrasonic longitudinal wave velocity to shear wave velocity ratio.