1997 Volume 18 Issue 5 Pages 273-280
Nondestructive evaluation of formability (r-value) in cold-rolled steel sheet with an electromagnetic acoustic transducer (EMAT) for the fundamental shear horizontal plate wave (SH0-wave) has been developed. First, the principle of nondestructive r-value measurement is described. Next the characteristics of the magnetostrictive type EMAT and the Lorenz force type EMAT for the SH0-wave were evaluated to permit an optimum sensor for nondestructive measurement. Based on the results, the system with the magnetostrictive type EMAT was fabricated and the capability for measuring r-values was evaluated using many samples. The system was confirmed to measure r-values with an accuracy of 1σ=0.065 nondestructively.
