Which ultrasonic testing method is effective for sizing flaws that are open to the ID or OD surface and are shallow to mid-wall?

Tip diffraction is an ultrasonic testing method particularly effective for sizing flaws that are open to the inside diameter (ID) or outside diameter (OD) surface and are shallow to mid-wall. This technique utilizes the physics of sound waves to detect reflecting surfaces within a material, particularly when those surfaces are limited in depth.

When a flaw is present, the ultrasonic wave travels toward it and can be diffracted at the tip of the flaw. This diffraction creates a unique signal that can be analyzed to determine the size and depth of the defect. The sensitivity of tip diffraction makes it ideal for shallow flaws, as the energy is concentrated at the flaw tip, resulting in a more reliable signal.

In contrast, other methods like direct transmission and longitudinal wave testing may not focus as effectively on the complex interaction of waveforms with shallow flaws. While angle beam reflection is useful for certain types of defects, it is not typically optimized for sizing shallow cracks or flaws as tip diffraction is. Therefore, for the specific context of shallow to mid-wall flaws open to the surface, tip diffraction stands out as the most suitable ultrasonic testing method.