Abstract
The influence of surface roughness on magnetic measurements of Reactor Pressure Vessel Steels was investigated by applying two types of magnetic, non-destructive measurement on nuclear reactor pressure vessel steel samples: magnetic adaptive testing (MAT) and magnetic Barkhausen noise measurement (MBN). The surface roughness was modified by primary and secondary machine cutting forces. Different settings of machine cutting produced different surface conditions. It was found that for both measurements a monotonic correlation was found to exist between magnetic parameters and surface roughness. Results of the MAT measurements found that the correlation depends on the speed (i.e., on the applied slew rate) of the magnetizing current. In a similar fashion, results from the MBN method show good agreement with MAT, where the response diminishes with an increase in surface roughness. The results show the importance of accounting for surface condition in the interpretation of results of non-destructive magnetic testing.
Highlights
Systematic nondestructive inspection of safety-critical structural components of power plants, bridges, pipelines, vehicles, etc., is essential in various industrial sectors
During the electro-magnetic hysteresis cycle, such pinning sites prevent the movement of the domain walls within the material, which is the premise behind Barkhausen noise phenomena [14]
The outcomes of magnetic adaptive testing (MAT) method, applying a faster slew rate of magnetizing current, resulted in a remarkably good correlation with the BNM method using the signal measured in the transversal direction
Summary
Systematic nondestructive inspection of safety-critical structural components of power plants, bridges, pipelines, vehicles, etc., is essential in various industrial sectors. The advantages (large sensitivity, good reproducibility) of this method have been proven in the past [8] Another well-known and frequently used magnetic method is the Barkhausen noise (MBN) technique, which is a useful technique for investigation of defects in the surface layer, microstructure changes, and residual stresses [9,10,11,12,13]. The principle behind Barkhausen noise is when a continuously changing electro-magnetic field (H) is applied to a material, a response of magnetization (M) in the form of discontinuous changes in magnetization occurs due to when the domain walls encounter pinning sites. During the electro-magnetic hysteresis cycle, such pinning sites prevent the movement of the domain walls within the material, which is the premise behind Barkhausen noise phenomena [14] These methods can be successfully used in NDT, there exists a serious drawback in magnetic measurements: the influence of the surface condition on the measured quantities. Within the present work, (i) the results of the MAT measurement on the same sample series having different surface roughness were analyzed, (ii) the results of MBN measurement performed on the same series of samples were considered and (iii) the MAT results were compared with the MBN measurements
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
