Ultrasonic Infrared Thermal Wave Technology and Its Applications in Nondestructive Evaluation

The ultrasonic infrared thermal wave method is a new nondestructive testing technique. It is remarkably sensitive and convenient for detection of small vertical cracks, such as fatigue cracks in metals. Pulses of ultrasonic launched by the ultrasonic emitter as heat source are excited into the sample, if there are some cracks in the material, they will be revealed through their heat generation, as the resulting surface temperature distribution which is observed by an infrared camera. A computer collects and processes the thermal images according to different properties of samples to get the satisfied effect. In this paper, firstly, a steel plate and an organic glass plate with fatigue cracks we designed were tested, the thermal image showed the subsurface cracks intuitively. Then we tried to test five laser welded seams which are welded by different welding powers, and the results gave some advices in selecting of laser power, which is an important factor in evaluating the quality of the welded seams. The ultrasonic infrared thermal wave nondestructive detection promises to be a sensitive, fast, wide-area, intuitively interpretable nondestructive evaluation technique that can be used on a wide variety of materials. It is significative for the nondestructive testing in manufacture produce and applications of aviation.