Development of a weld enamel technology for the installation of steel pipelines with an internal silicate-enamel coating

The reliability of operation of steel pipelines is determined by the corrosion resistance of not only the inner surface of the pipe body itself, but also the inner surface of the welded joint. When welding pipelines with a silicate-enamel coating, the reverse weld bead does not have a protective coating, and in addition, in the heat-affected zone, as a result of high-temperature exposure, the enamel burns out, the enamel evaporates, as well as the formation of pores, bubbles, macro-, microcracks. With further operation, it is in the places of welding that the corrosion process begins, since the metal remains unprotected. Therefore, in the course of the study, a technology was developed for enameling a weld. The composition of the paste for processing the ends of the steel pipe and the method of its application are developed. The optimal current strength during welding was determined to ensure uniform formation of silicate-enamel coating during welding. The possibility of using this method in conditions of subzero temperatures was studied. The features of the formation of a silicate-enamel coating during welding, the types and causes of the formation of defects, and the corrosion resistance of the resulting layer were studied. (C) 2020 Elsevier Ltd. All rights reserved.