Use of Ultrasonic Techniques to Assess the Mechanical Properties of Steels

Abstract

A computer-based ultrasonic test system was assembled to automatically acquire ultrasonic velocity and attenuation data on commercial steel samples. Attenuation data on plain carbon plate steels showed significant statistical correlation to ferrite grain size and to yield strength, but more consistent coupling is needed if the technique is to be developed into an on-line test for steel plates. Surface-wave velocity and attenuation data on sheet steel samples undergoing tensile testing (acoustoelastic data) were found to be weakly correlated to yield strength. Variations in residual and bending stresses precluded consideration of acoustoelasticity as as on-line technique to determine properties of sheet. Our recent work has focused on nondestructively determining the anisotropy in velocity and attenuation in sheet steel samples, and on relating this data to mechanical properties. The potential for developing an on-line technique to determine crystallographic texture looks promising, based on recent tests using electromagnetic acoustic transducers (EMATs) to generate shear-wave and Lamb-wave modes in sheet.