METHOD OF CORROSION PROTECTION OF INNER SURFACES OF PIPES Russian patent published in 1995 - IPC

FIELD: anticorrosive treatment of surfaces. SUBSTANCE: layer of corrosion-resistant steel is applied to end sections of inner surfaces of pipes over length exceeding length of zone of thermal effect of welding on polymer coating with subsequent application of layer between borders of these zones. At least one groove is made in applied steel layer outside thermal effect zone over circumference at side opposite to pipe end face. To end of pipe, diameter of bottom of each adjacent groove decreases by value not less than value of thickness of coating; size of side wall at side of end face of each groove exceeds size of other wall of groove by the same value. EFFECT: enhanced quality of protection. 1 dwg