How to Test Better

Practical examples for optimization of nondestructive testing of various objects are presented. Ultrasonic testing of some welds does not require testing the basic metal even in the heat-affected zone. Meanwhile, the basic metal sometimes contains semitransmitting foreign inclusions. Ultrasound has to pass through these inclusions to reach the welded seam zone. As a rule, such inclusions do not affect the mechanical properties of a welded seam and, naturally, they are not defects. In principle, such a welded seam can be tested but the sensitivity has to be increased to compensate attenuation due to passage through metal "contaminations." The problem is, to what extent should the sensitivity be increased. I propose that the increase in sensitivity be determined as follows. Two inclined transducers (similar to those used for testing) should be connected as a separation circuit and directed toward each other to obtain the ground signal in the region of the base metal. Then one has to measure the amplitudes of ground signals in the regions with and without contaminations. The additional attenuation in the defect region gives the necessary value for the increase in sensitivity.