Ultrasonic Non-Destructive Testing at Elevated Temperatures
1. The sonic velocities of a stainless steel specimen are measured in a laboratory test. The wave speeds are recorded and plotted versus temperatures, and a curve fit is obtained using the least squares method. The resulting relation is;
V = 2.7x10-4 *T2 - 0.54*T + 5806 meters/second, where V = wave velocity, and temperature T is in units of °C
If the specimen has a coefficient of thermal expansion of α = 1.3x10-6 °C-1, and has a thickness of 0..50 inches at room temperature (20°C),
(A) find the longitudinal wave sonic velocity at room temperature.
(B) find the period (i.e. the distance between similar echo wave-front peaks of the oscilloscope display) for the specimen at room temperature of 20°C,
(C) calculate expected period at temperatures of 500°C, and 1000°C.
(D) find the thickness of the specimen at temperatures of 500°C, and 1000°C.