Multi-Frequency Eddy Current Testing
Multifrequency eddy current testing uses multiple frequencies to detect defects by compensating for interfering influences such as lift-off variations or material differences. This leads to precise isolation of real defects.
Physicochemical Mechanism of Action
Multifrequency eddy current testing uses an eddy current sensor that is excited with several frequencies simultaneously. Each frequency responds differently to the material structure and the defects present. By analyzing these differences, interference such as lift-off variations or material properties can be filtered out, allowing real defects to be detected accurately.
Metallurgical Relevance & Welding Risks
In weld inspection, lift-off variations and material differences can cause errors that distort the results. Multifrequency eddy current testing minimizes these error sources by using multiple frequencies, which helps in accurate defect detection and increases the reliability of the inspection.
Workshop Practice & Instructions
To successfully perform multifrequency eddy current testing, consider the following steps:
1. Frequency Selection: Use at least three different frequencies (e.g., 50 kHz, 100 kHz, and 200 kHz) to achieve broad detection capability.
2. Sensor Adjustment: Adjust the sensor to optimally cover the specific testing conditions (e.g., lift-off, material type).
3. Data Analysis: Analyze the results from each frequency separately and compare them to identify interference and isolate real defects.