In contact testing, what is the entry surface indication also referred to as?

In contact testing, the entry surface indication is commonly referred to as the "Entry surface echo." This term specifically identifies the reflection that occurs at the interface between the testing probe and the surface of the material being examined. When an ultrasonic pulse is emitted, it travels through the probe into the material, and when it hits the surface, a portion of that pulse is reflected back to the transducer, which generates a distinct echo on the display of the ultrasonic testing equipment.

This echo is critical because it serves as a reference point for evaluating other signals that may indicate flaws within the material. It helps in establishing the time scale for measuring distance to different features within the material, such as defects or the back wall reflection.

Understanding this concept is essential for interpreting the data accurately during the inspection process. Hence, recognizing the entry surface echo is fundamental for anyone involved in ultrasonic testing, as it lays the groundwork for the analysis of deeper signals that follow.