Sound propagation time
The time an ultrasonic pulse needs to travel from the probe to the reflector and back. It helps determine the exact depth of flaws.
Physical-Chemical Effect Mechanism
An ultrasonic pulse is sent into the test object and reflects at interfaces within the material. The time the pulse takes to travel from the probe to the reflector and back is called the time of flight.
Metallurgical Relevance & Risks in Welding
The time of flight indicates the depth of a flaw. An inaccurate measurement can lead to wrong depth indications and thus misdiagnosis of defects in the material. This can create safety risks because potentially dangerous defects may go undetected.
Workshop Practice & Instructions
To measure the time of flight accurately, take these steps:
1. Make sure the test object is clean and dry.
2. Choose a suitable ultrasonic transducer and receiver with the right frequency.
3. Set the measurement parameters like sound velocity and waveform correctly.
4. Send the ultrasonic pulse and measure the time until the reflector is reached and the pulse returns.
5. Use the formula: Depth = (time of flight / 2) * sound velocity.