Ultrasonic Testing equipment works with the principle of sending a pulsed beam of high-ultrasound from a handheld transducer, which is placed upon the surface of the object being tested.
This wave will be disturbed and then partially returned from spots with internal imperfection or from the back of the material wall. Capturing and analysing the return sound collect useful information, which are displayed upon the screen of the ultrasonic equipment, presenting the amplitude of the pulse and the duration taken for return to the transducer.
By measuring this sound a skilled Ultrasonic Testing operator can identify location and size of imperfection, respectively the wall thickness of the material. Acceptance criteria define whether or not the indication is non-acceptable (a defect) or not.