Which of the following is NOT a feature of Ultrasonic Testing?

Ultrasonic Testing (UT) is a widely used Nondestructive Testing method that employs high-frequency sound waves to detect internal flaws in materials. One of the key features of UT is its ability to identify and assess internal imperfections, such as cracks and voids, without requiring direct visual access to the material being tested. This makes it particularly advantageous, as operators can examine components that are not readily visible or accessible, such as welds or areas inside complex structures.

The assertion about needing direct visual access to the material is inaccurate when it comes to UT, as the technique relies on sound wave transmission and reflection to gather information about the material's structural integrity. This allows the testing to be conducted in a variety of settings, including those where visual inspection would be impossible or impractical.

Additionally, ultrasonic testing provides high sensitivity, enabling the detection of small defects, and can be effectively applied in challenging environments, such as underwater or in the presence of electromagnetic interference. These traits highlight the versatility and effectiveness of UT in identifying flaws that could compromise the safety and performance of critical components.