Diagnostic Examination of P265GH Boiler Steel Plate Using the Barkhausen Method

The article presents the results of diagnostic examination of P265GH boiler steel plate. During blanking, cutting and cold forming of elements from this plate, their spontaneous plastic deformation and warping took place, indicating an unfavourable internal stress state of a considerable magnitude occurring in the steel plate. In order to identify the causes of this situation, examinations were carried out, which included a microstructure assessment and a Vickers hardness test. In view of the absence of clear differentiation, in terms of both structure and hardness, in different steel plate areas, diagnostic examination was performed by the Barkhausen magnetic method, which included the determination of the principal direction of residual stresses and the determination of their anisotropy based on the measurement of the effective value of Barkhausen noise. As their result, a significant anisotropy of residual stresses was revealed on the steel plate surface. Moreover, the adverse phenomenon of perpendicularity of the principal directions of stresses was found to occur on the opposite plate surfaces, being the direct cause of warping of elements cut out from the plate