RESTORATION OF DELETED MARKINGS ON THICK-WALLED OBJECTS USING THE MAGNETO-OPTICAL IMAGING METHOD (MOI)

Abstract

The article demonstrates the effectiveness of the magneto-optical imaging (MOI) method for restoring deleted embossed markings on thick-walled steel objects. This method has also proven effective for examining large marking areas. The task of restoring markings on large metal objects is relevant not only due to their value but also because, for military objects, resolving such issues provides essential identification information. Factory serial number markings on these objects are often located on inclined or curved surfaces, which pose challenges for liquid-based methods of investigation. A concise overview of the physical principles and investigation algorithm of the magneto-optical imaging (MOI) method is presented, along with the parameters of the area under study and the duration of the investigation. Currently, the physical processes of internal stress formation and the sensitivity of the MOI method for thick metal layers have not been sufficiently studied. However, practical application of the MOI method demonstrates its successful use for examining thick-walled products. Examples of restoring deleted original markings on objects made of two different types of steel are shown. For steel with higher mechanical properties, visualization provides a clearer image of the deleted markings compared to soft, ductile steel. The results of surface analysis with removed markings were sufficient to address the tasks of restoring deleted symbols and obtaining the necessary identification data in both cases. The magneto-optical imaging (MOI) method is non-destructive, offers rapid investigation, and enables the examination of large surfaces through “mapping” using stitched images. It also allows for the analysis of curved and inclined surfaces and provides adjustable sensitivity. The equipment used is designed for field operations within a wide temperature range, characterized by mobility and autonomy. The magneto-optical visualization method is successfully applied in expert investigations, particularly for thick-walled objects.