Application of a Fourier Transform-Phase-Slope Technique to the Design of an Instrument for the Ultrasonic Measurement of Texture and Stress

This paper describes the development of an ultrasonic instrument to measure texture (preferred grain orientation), stress, and related physical properties in metal sheets in industrial environments. The technique is based on precise measurements of the speed of guided modes, including angular variations, and is made practical by the use of EMAT transducers, which require no couplant. The instrument is expected to find important initial applications in predicting sheet metal formability, either as a process control tool in the rolling mill or as a quality control tool in a stamping shop. Since the instrument will offer an improved measurement capability not presently available to industry, a much broader range of applications may develop, including measurements of stress and porosity in sheet and other simple geometries