| 摘要 |
PURPOSE:To measure the graphite spheroidizing ratio of cast iron without sampling and processing a test piece from a main body by arranging a transmitting vibrator and a receiving vibrator at a definite distance and allowing ultrasonic wave to be incident to a specimen to calculate the sonic velocity of a surface wave. CONSTITUTION:A surface wave probe 9 is contacted with a product main body 8a through a contact medium, and a transmitting vibrator 9a and a receiving vibrator 9b are arranged at a definite distance in the probe 9. An ultrasonic wave is emitted from the transmitting vibrator 9a and a surface wave 10 subjected to mode conversion is allowed to propagate through the surface layer part of the main body and received by the receiving vibrator 9b to be displayed on CRT 3. At this time, the sonic velocity of the surface wave is calculated from the propagation distance (l) and propagation time (t) of the surface wave. From said sonic velocity and a Young's modulus, operation is performed according to a predetermined formula to calculate the graphite spheroidizing ratio of cast ion. Further, the transmission frequency of the probe 9 is changed and the propagation depth of the surface wave is changed to measure the graphite spheroidizing ratio at a different depth. Since the sonic velocity of the surface wave is measured, the sampling of a test piece from the product main body is made unnecessary and the spheroidizing ratio can be rapidly measured at an arbitrary depth. |
