| 摘要 |
<p>PURPOSE:To perform on-line decision of the material characteristics of a steel plate and its anisotropy during traveling by measuring the rate of propagation of elastic wave in the steel plate. CONSTITUTION:A Y-cut crystal oscillator is used as a transverse wave transmitter. A radio receiving terminal 1 and a transmitting terminal 2 are made in one piece and are so set that both are located always at a constant distance. The center C of a bar connecting both is aligned roughly to the center of the plate width on the traveling line of a steel plate P, and the bar is made rotatable around the central axis C. Water nozzles 3, 4 are provided in order to acoustically couple a transmitter and a surface to be inspected as well as a receiver and the surface to be inspected. The terminals 1, 2 are turned around the normal axis of the steel plate to measure the rates of propagation in the plural directions within the surface. Usually, the values in the three directions; a rolling direction, a 45 deg. direction and a 90 deg. direction, are measured at constant periods or intermittently. The average rates of propagation of the steel plate or the average modulus of rigidity of the steel plate is calculated from the measured values of the rates of propagation in the respective directions; at the same time, the in-surface anisotropy of the material characteristics of the steel plate is evaluated from the modulus G of rigidity in the respective directions.</p> |
