In ultrasonic testing, what is the function of a wedge?

The function of a wedge in ultrasonic testing is critical for altering the angle at which ultrasonic waves enter the test material. By using a wedge, it's possible to introduce sound waves at various angles, which is essential for achieving the desired mode of propagation (like longitudinal or transverse waves) and for optimizing the inspection of components with different geometries.

When the ultrasonic waves travel through the wedge, they change direction upon exiting into the test material. This ability to change the angle allows for better examination of welds, joints, and areas that may not be accessible with direct ultrasonic testing. Moreover, wedges can help improve the sensitivity of the testing by ensuring that the sound waves strike the material at the best possible angle for detecting flaws.

Other options, such as amplifying the signal, cooling the transducer, or increasing testing speed, do not accurately represent the purpose of a wedge in ultrasonic testing. The wedge is specifically designed to facilitate the entry angle of sound waves rather than altering signal strength or affecting the operational performance of the transducer.