Phase Angle Analysis
Phase angle analysis measures the phase difference between excitation signal and eddy current response to quantify defect depths or material separations. A small phase angle indicates good continuity, while a large angle signals problems like cracks or separations.
Physical-Chemical Mechanism of Action
Phase angle analysis is based on measuring the time interval between the excitation signal and the eddy current response. A phase shift indicates that the material is not uniformly penetrated or that it is interrupted in certain areas.
Metallurgical Relevance & Risks in Welding
A large phase angle can indicate flaws, cracks, or separations in the material. This can lead to inconsistent weld strength and an increased risk of cracking. A high phase difference also indicates poor contact between the weld rods.
Workshop Practice & Action Instructions
To perform phase angle analysis, a special measuring device is used. The excitation signal and the eddy current response are recorded and compared. A phase angle of less than 10 degrees is normally acceptable. For an angle above 20 degrees, further inspection or repairs should be carried out.