How to Choose an Ultrasonic Flaw Detector for Your Workpiece

Start with the workpiece, not the instrument

Choosing a flaw detector starts with clarifying what you need to find and under what conditions.

1. Set the frequency by material

Coarse-grained materials such as castings and austenitic stainless steel attenuate heavily — use low frequency (2 MHz) for better penetration. Thin-walled and precision parts suit high frequency (5–10 MHz) for resolution and sensitivity.

2. Match the probe to defect location

• Near-surface and internal defects: straight (longitudinal) probe
• Inclined near-surface defects: angle (shear wave) probe
• Thin walls and highly attenuating materials: pitch-and-catch probe

3. Choose the mode by site conditions

For complex welds, B-scan or C-scan helps locate indications. For pipeline surveys, use thickness mode with automatic statistics. See the TJ-UT260 ultrasonic flaw detector for full specifications.

Field verification checklist

• Verify sensitivity on a test block of the same material as the workpiece
• Record sound velocity and keep it consistent within a batch
• Cross-check critical welds by scanning from both sides