A method for metallic structure maintenance is disclosed. The method includes a magneto-graphic/Magnetic Tomography technique to identify stress-related defects. The method is specifically optimized for extended, non-accessible underground and underwater metallic structures in providing quality control, emergency alarms as well as timeline planning for structural repairs and maintenance work. Examples of the method implementation include pipes for oil and gas industry, detection of flaws in rolled products in metallurgical industry, welding quality of heavy duty equipment such as ships reservoirs, etc. It is especially important for loaded constructions, such as pressured pipes, infrastructure maintenance, nuclear power plant monitoring, bridges, corrosion prevention and environment protection.