Ultrasonic testing is a non-destructive testing process used to detect internal flaws within a material. To begin, a transducer is used to transmit ultrasounds though a material forming the initial indication (contact surface of the transducer and the sample) and the back-wall echo (opposite side to which the transducer is placed) on the screen of the testing machine (oscilloscope). These two indications form the length of the sample. Should a flaw/defect exist, an indication will appear between the initial and the back-wall echo. The size of the internal defect can be determined by taking ultrasonic readings from the area surrounding the defect. Ultrasonic testing is thus an integral part of quality assurance testing due to its ability to detect internal defects.
Donhad employs the use of a Sonatest D-10 machine when performing ultrasonics testing. Prior to any test, the machine is first calibrated to the desired specimen length to ensure an accurate representation of the specimen. Testing is performed according to ASTM A388 (Standard practice for ultrasonic examination of steel forgings) to ensure the integrity of the test.