Anticorrosion Protection of Welded Joints of Oil Pipelines

Currently, a problem of destruction of field and interfiled pipelines is topical. One of effective ways to increase an operational reliability of pipes is to protect them with different coatings. To protect the inner surface of oil pipelines the polymer coatings are used which cover the full length except the end sections – zones of mounted welded joints. Oil companies are interested in development of a technology of metal coating applying to the end sections, which provides both reliability of protection system of inner surfaces of pipes, and workability and high speed of mounting of pipelines. This paper shows the analysis of protection methods of pipeline end sections. The tests of metallized coatings are held. We identified the significant shortcomings of metallized coatings. There is a held experiment on applying of corrosion resistant coating by surfacing. There are the calculated heating zones while the surfacing operation. We defined the minimum necessary length of section for applying the protection coating. A chemical analysis showed that the expected structure in a surfaced coating is an austenite with inclusions of ferrite and martensite. Metallographic research showed that the protection layer is fully melted with a base metal of a pipe and represents a homogeneous structure without pores and slag inclusions. Mechanical tests confirmed the compliance of pipe metal properties to the requirements of normative and technical standards.