METHOD AND DEVICE FOR NONDESTRUCTIVE QUARITY TESTING OF DUCTILE IRON PRODUCT

摘要

PURPOSE:To measure ununiformity of material of a ductile iron product in wider extent and more accurately and rapidly, by a method wherein attenuation of ultrasonic wave is measured by water-immersion flaw detecting method. CONSTITUTION:A pulse oscillating circuit 3 transmits pulse power to a probe 4 depending on signal of a synchronous signal generating circuit 2 and converts it into ultrasonic beam, and then the converted beam is radiated through a contact medium 9 onto a specimen 8. Reflected ultrasonic beam is received by a probe 4 and converted into electric signal and then amplified by an amplifier 5. In A scope display 10 controlled by a sweep circuit 6 and a distance scale circuit 7, abscissa axis is used as the time base and echo level representing intensity of the received wave is displayed in ordinate axis during sweeping at a prescribed speed. Transmission pulse T is first displayed, and subsequently front surface reflected wave (S echo), bottom surface reflected wave (B1 echo) and inside reflected echo (B2 echo) are displayed in order. Attenuation constant is estimated by logarithm of ratio of level in echoes B1, B2 and stroke of ultrasonic beam between echoes S, B1.