Thermographic Lock-In Phase Angle Evaluation
Thermographic lock-in phase-angle evaluation is a method for depth determination of subsurface defects by analyzing periodically excited thermal waves, independent of emissivity. It increases the robustness of non-destructive testing.
Physical-Chemical Mechanism of Action
This method uses the properties of periodically excited thermal waves to determine the depth information of subsurface defects. It analyzes phase angles to quantify heat emission and absorption.
Metallurgical Relevance & Welding Risks
This method is especially useful in inspecting weld integrity, as it can sharply locate defective or missing weld volumes. Incorrect interpretation can lead to inaccurate results and misunderstandings in quality assurance.
Workshop Practice & Procedures
To use this method successfully, follow these steps:
• Use a qualified thermography device with lock-in function.
• Ensure the thermal wave is applied periodically and homogenously to the test object.
• Analyze the phase angles to determine depth information.
• Compare results with reference data or standard specifications.