Abstract
A detailed report of the theory, technique and application of electrolytic derusting to the cargo tanks of United States Navy tankships. After a discussion of the various aspects of anodic and cathodic cleaning of rust from steels, the theory of the process, together with an account of patents, army use of the method and initial navy testing and applications is reviewed.
Details of the laboratory investigations preceding the application of the descaling method are given, including apparatus and materials. Effects of anode spacing, electrolyte composition, temperature, effect on faying surfaces and on dissimilar metals (aluminum, zinc, lead and brass), additions of sulfuric acid to electrolyte, current reversals, detergents, hydrogen embrittlement are surveyed. Results using, anodes of magnesium, aluminum, zinc, copper and platinum are reported. Volume of gases given off by the various anodes is measured.
Reports on the electrolytic descaling of nine vessels are given, including an estimate of the final tank conditions, optimum current density, anode area, current distribution, washing down operations, intermittent flushing, hydrogen evolution and cost comparisons with conventional cleaning methods. Specific recommendations and an account of the practical details involved in the procedure are given. 15 tables, 33 figures.
