Progress in the post weld residual stress evaluation using Barkhausen effect meter with a novel rotating magnetic field probe

摘要

We report about the progress in post weld residual stress evaluation using the Barkhausen effect (BE) meter with a rotating magnetic field probe. The novel probe of the BE meter contains two C-core electromagnets and a searching coil with the ferrite antenna. This meter enables automatic measurements of BE intensity envelopes at different angles of magnetizing field. The full process of measurement at a given position of the probe takes only about 30 seconds. Integrals of those envelopes and peak to peak amplitudes are calculated for each angle and finally rotation of main axes are found. This novel meter enables thus a very quick detection and visualisation of material anisotropy as well as of the stress state. We present here, as an example, the full procedure of assessment of distributions of residual stresses over the welded plates including process of calibration. Two model like but-weld samples were made of nearly isotropic (grade S235JR, EN 10025-2) and anisotropic (grade S460ML, EN 10025). These results make evident that this new BE meter is very suitable for quick inspection of residual stress introduced by welding process.