What type of non-destructive testing is best suited for detecting subsurface flaws?

Ultrasonic Testing is best suited for detecting subsurface flaws because it uses high-frequency sound waves that are transmitted into the material being tested. When these waves encounter a discontinuity, such as a crack or void, they are reflected back to the surface where they are detected by the equipment. This method allows for the detection and characterization of defects located beneath the surface, including those that are not visible through other testing methods.

Additionally, ultrasonic testing can provide information about the depth and size of the detected flaws, making it a highly effective method for evaluating the integrity of pressure vessels. Its ability to assess materials without affecting their integrity is a significant advantage in critical applications where performance and safety are paramount.

In comparison, while methods like Magnetic Particle Testing and Dye Penetrant Testing are effective for surface flaws, they cannot detect issues that are located beneath the surface. Visual Inspection also relies on direct line of sight and is limited to visible areas, thus lacking the capacity to identify subsurface issues as effectively as ultrasonic testing.