The Difference Between Radiographic And Ultrasonic Testing
Radiographic testing and ultrasonic testing are two methods of non-destructive testing (NDT). These two methods are used to inspect the internal integrity of the weld, and do not destroy the weld like destructive methods do. Radiographic and ultrasonic testing are the two most common NDT methods for testing the quality of the weld. Although these two are part of the same group and test for the same thing, they use different techniques. Read more about the differences between radiographic and ultrasonic testing below:
Ultrasonic testing is a form of weld inspection that uses vibrations, of a higher frequency than sound waves, to test for discontinuities in a weld. This ultrasonic energy is sent through the weld being tested. The vibrations move through the weld, uninterrupted, and bounce back if they come across a discontinuity. Through the constant reflection of these vibrations, the discontinuity can be located. Ultrasonic testing can be used to inspect ferrous and nonferrous materials and it is suitable for use on thicker materials that are not easily accessible. Ultrasonic testing is better at detecting plain, fine defects that radiographic testing cannot detect.
Unlike ultrasonic testing, radiographic testing uses x-rays to detect defects. This type of testing works in the same way as medical x-rays. The radiation is sent through the weld onto a film and is depicted as a photograph. The defects of the weld, such as pores or cracks, will be shown as dark spots on the photograph. Radiographic testing is different to ultrasonic testing when it comes to access. Radiographic testing needs the weld to be accessible from both sides.