Methods of Experimental Verification to Control Corrosion State and Condition of Protective Coatings of Pipe-lines with Multilayer and Weight Coatings

Issue 1(79) 2016
Pages 47-54

S.N. Asharin

LLC «Gazprom VNIIGAZ», Razvilka, Moscow region

Keywords: electrochemical protection, methods of control, concrete pipelines, weight coatings

Constructions of «tube in tube » (annular tubes) with outer metallic, polymeric or metal-polymeric shells are one of the most popular and widely applied designs of pipes with concrete coatings factory-built. Control of corrosion state and the condition of the main anti-corrosion protection coatings of pipeline sections with multilayer thermal and weight coatings of «tube in tube» design has limitations due to the significantly higher transition resistance of «construction – environment» compared with pipes without external polymer or metal-polymer shell. A series of experiments was performed to test the possibility of providing specified ECP parameters and methods to control corrosion state of pipelines with similar structures. According to the results of experimental studies, it was established that such pipes laid in the ground may be protected by current of cathode protection. Herewith, control of security of pipe metal can be realized using a potential sensors, reference electrodes and sensors of corrosion rate established in weight coating under metal-polymer shell.