Differential Probe
A differential probe is an eddy current sensor system with two opposing windings that detects local irregularities like cracks while suppressing homogeneous backgrounds. It is used in the workshop to test weld quality.
Physical-Chemical Mechanism of Action
A differential probe consists of two windings connected in opposition. One winding generates a magnetic field while the other detects it. The voltage difference between the two windings is measured and processed.
Metallurgical Relevance & Risks in Welding
The differential probe is especially good at detecting local irregularities like cracks or deformations in the weld. However, it may have difficulty distinguishing homogeneous backgrounds from actual defects. This can lead to false alarms and increase inspection effort.
Workshop Practice & Instructions
To use the differential probe effectively, follow these steps:
1. Make sure the probe is clean and free from contaminants.
2. Adjust voltage settings to match the material being tested.
3. Move the probe slowly over the weld, watching for anomalies in voltage difference.
4. Document all detected defects and compare them to reference standards.