Which non-destructive testing (NDT) method is commonly used in welding?

Ultrasonic testing (UT) is a widely used non-destructive testing method in welding because it effectively detects internal flaws in welds without causing any damage to the material being tested. This method uses high-frequency sound waves that are transmitted through the material. When these sound waves encounter a flaw or an inclusion, such as a crack or void, they scatter or reflect back. The time it takes for the sound waves to return is measured and analyzed, providing information about the size, shape, and location of any potential defects.

Ultrasonic testing is appreciated for its sensitivity and precision, making it suitable for various welding applications, especially in critical structures where safety is paramount. It allows for the inspection of complex geometries and is often used in industries like aerospace, automotive, and manufacturing.

In contrast, while radiographic testing also serves as a non-destructive method for finding faults, it is based on the use of X-rays or gamma rays, which may present safety concerns. Thermographic testing deals with temperature changes and is less common in the context of weld inspection. Destructive testing, meanwhile, is fundamentally different, as it involves damaging the specimen to assess its mechanical properties. Hence, ultrasonic testing stands out as the most suitable choice in this context