Electromagnetic Acoustic Transducer Testing
Ultrasonic testing with EMAT transducers generates and detects sound waves directly in the material via electromagnetic alternating fields, eliminating the need for coupling media.
Physicochemical Mechanism of Action
Sound waves are generated in a metallic material by electromagnetic alternating fields (EMW) and directly detected. This process uses electricity to generate sound waves without the need for an external coupling medium such as water or oil.
Metallurgical Relevance & Risks in Welding
EMW ultrasonic testing enables precise monitoring of the weld and detection of flaws such as cracks or pores. Without a coupling medium, testing is possible in dry environments, which is particularly advantageous for hard-to-reach surfaces. Incorrect setting of EMW parameters can, however, lead to inaccurate results and impair testing accuracy.
Workshop Practice & Instructions
To carry out a successful ultrasonic test with EMW transducers, the following steps must be observed:
1. Set parameters: The frequency and amplitude of the EMW alternating fields must be precisely set to generate the desired sound wave frequency.
2. Test environment: Ensure the workpiece is dry and free from surface contaminations, as these can affect detection.
3. Performing the test: Move the EMW transducer across the weld and collect data on sound wave amplitude and phase.
4. Evaluation: Analyze the recorded data for anomalies such as cracks or pores and compare them with acceptable standards.