Corrosion Protection of Cast Iron Pipeline by Polyethylene Sleeving and Application of Cathodic Current to It

Abstract

Characteristics of loose polyethylene sleeving in protecting buried cast iron pipelines from corrosion with and without the combined use of cathodic protection have been studied both in laboratory and field. Although the sleeving does not completely prevent water from entering onto the iron surface, it is effective in reducing corrosion and particularly pitting, if local defects exist in the film. Accelerated corrosion does not occur at and around a damaged film area. Cathodic current further ensures the protective effect by cathodically protecting exposed areas and by raising pH of water under the film.