RESEARCH OF CORROSION RESISTANCE OF HOT-ROLLED PIPES SUBJECTED TO SURFACE PLASTIC DEFORMATION USING CORROSION INHIBITORS

Abstract

The oil and gas industry is the main consumer of pipes of a wide grades and geometries, up to 18% of the total metal pool. The applied hot-rolled pipes have technological drawbacks in the form of scale on the surface, coarse-grained decarburized surface layers, high surface roughness. These factors are initiators and intensifiers of the development of corrosion and fatigue processes. Therefore, improving the corrosion resistance of hot-rolled pipes for the oil industry is an urgent task. To some extent, the problem is solved by the use of surface plastic deformation of (SPD) and various coatings – galvanizing, enameling, the use of inhibitors. Increasing the durability of machine parts by surface plastic deformation is widely used in industry to increase the resistance to low-cycle and high-cycle fatigue of machine parts. Surface plastic deformation is based on the ability of a metal surface to perceive permanent plastic deformation without breaking the integrity of the metal. SPD is one of the simplest and most effective technological ways to improve the performance and reliability of materials. Strengthening the surface layer of parts by plastic deformation is an effective way to increase their durability. Importantly, SPD improves resistance to corrosion and contact fatigue. At the same time, the use of only SPD does not solve the problem of corrosion resistance. The use of surface plastic deformation with a decrease in roughness increases the anti-corrosion properties of steel in non-aggressive environments with low humidity (closed storage). In the simulated conditions of aggressive environments, the degree of corrosion damage to steel subjected only to SPD increases sharply. The use of surface plastic deformation with corrosion inhibitors significantly increases the anticorrosive properties of the treated surface. Of the three materials used in these studies, the best result was shown by a corrosion inhibitor used for drinking water, as well as for protecting osmotic water lines, contains polyphosphate and sodium silicate. The obtained result is confirmed by three types of research carried out.