Indicating Echo
An indicator is a visible signal on a testing device that reacts to an acoustic impedance change in the material and helps in flaw evaluation.
Physical-Chemical Mechanism of Action
The indicator is based on measuring acoustic waves reflected by the material. This reflection changes the impedance and is captured by the testing device as a signal.
Metallurgical Relevance & Risks in Welding
A strong indicator can point to material defects such as cracks, pores, or incomplete fusion. These defects can impair the mechanical strength and reliability of the workpiece.
Workshop Practice & Instructions
When using ultrasonic testing (UT), the indicator value is recorded and compared with reference values. A high value suggests a possible defect that needs further investigation. If the indicator is too high, the weld should be re-inspected and repaired if necessary.