METHOD AND DEVICE FOR ULTRASONIC INSPECTION FOR PLANE AT INNER SURFACE OF COATING WALL

摘要

PURPOSE: To provide an ultrasonic testing method for an inner surface of a wall of a tubular coating for testing the number of surfaces of a coating and size of these surfaces in circumference direction of an inner surface of the coating and variation of thickness of the coating over one rotation particularly very accurately. CONSTITUTION: A tubular coating 1 has an essentially prism shape inner surface which has succeeding surfaces. An ultrasonic testing head 3 can discharge the ultrasonic in shape of a pulse from outside the coating 1 and the ultrasonic passes through a wall of the coating 1 and scans the wall over its whole periphery. The number of discharges of the ultrasonic pulse is adjusted as function of circumference scanning speed of the coating 1. The ultrasonic signal reflected by the inner surface of the wall of the coating 1 is recorded and the reflected signal is analyzed so as to test the number of the surfaces and size of the surface and variation of thickness of the coating over one rotation.