INTRODUCTIONTexture in sheet metal must be controlled in the rolling process to assure the fabrication properties desired in later manufacturing. Drawability is one of the required engineering properties in a family of applications including beverage cans, propane tanks, and automotive parts.The para~eters measured to predict drawability are the average plastic strain ratio r in steel and the orientation distribution coefficients (Ws) in aluminum. The fundamental measurement of r is by tensile testing of coupons taken to 20% elongation. Because of the fact that maximum drawability in c~bic metals coincides with a texture which maximizes the Young's modulus E in the plane of the sheet which can also be measured on tensile coupons, there is a correlation between rand E with vibrating coupons. This method and the tensile method are destructive because coupons must be cut. In aluminum, the earing on drawn cups is a measure of drawabili ty.As longitud~nal Lamb wave ultrasonic velocity in a sheet depends on Young's modulus E (and on Poisson's ratio), it now is possible to measure E ultrasonically and to predict r. The relevant Ws can also be measured ultrasonically. Measurements of rby means of ultrasonics have been carried out by several laboratories. The method of choice for exciting the waves is EMAT technology because it is noncontacting and nondestructive. These features raise the possibility of using EMAT technology on moving steel sheet such as on rolling lines, continuous annealing lines, and blanking lines where rmeasurement could contribute to process control and quality assurance.EMAT technology for So Lamb waves in steel sheet was chosen for building an industrial grade instrument to measure r and the Ws automatically. Appropriate signal processing techniques and sensor configurations were used in a computer-controlled automatic instrument. To date the instrument has been used in a static configuration.In this paper, the instrument development and testing will be reported.
