Ultrasonic examination:Ultrasonic TestingIt is called UT for short. The basic principle is a nondestructive testing method which uses the difference of acoustic properties of materials and defects to test the internal defects of materials. There are many types of ultrasonic wave when it propagates in the medium, and the most commonly used ones are P-wave, S-wave, surface wave and plate wave. The longitudinal wave can be used to detect the inclusion, crack, shrinkage, white spot, delamination and other defects in metal ingots, billets, medium and thick plates, large forgings and simple shaped workpieces; the transverse wave can be used to detect the circumferential and axial cracks, scratches, pores, slag inclusions, cracks, incomplete penetration and other defects in pipes; the surface wave can be used to detect the surface defects on simple shaped castings The plate wave can be used to detect the defects in the thin plate.