How do you troubleshoot and resolve common problems in remote field testing NDT?

1 Probe selection

One of the most important factors in RFT is choosing the right probe for the application. Different probes have different frequencies, shapes, sizes, and coil configurations that affect their sensitivity, resolution, and depth of penetration. The probe should match the tube diameter, material, and expected defect type and location. For example, a low-frequency probe can detect deep defects, but it may miss shallow or small ones. A high-frequency probe can resolve fine details, but it may not penetrate thick walls or coatings. A bobbin probe can inspect the entire tube circumference, but it may not fit into bends or elbows. A plus-point probe can navigate curves and corners, but it may not cover the full cross-section.

3 Data analysis

The final step in RFT is analyzing the data and interpreting the results. Data analysis involves comparing the signal response from the inspected tube to a reference signal from a calibration tube or a baseline signal from a defect-free section. The signal response can be displayed in various formats, such as impedance plane, time-based, or distance-amplitude correction (DAC) curves. The signal response can indicate the presence, size, shape, and location of defects, as well as the wall thickness and condition of the tube. However, data analysis also requires some skill and experience, as some defects may not be easily detected or distinguished from other features, such as tube supports, welds, or bends. Data analysis also requires some knowledge of the tube geometry, material, and environment, as these factors can affect the signal response and the defect characterization.