CATHODIC PROTECTION OF STEEL UNDERGROUND

Underground corrosion of steel pipe has been estimated to cost $600 million (approximately £200 million) annually, in the United States. Efforts to reduce this toll have been stimulated since 1941 by heavy defence requirements for steel and other metals. Workers in the field have learned that underground corrosion can be greatly reduced by cathodic protection techniques, in which the structure is maintained at a suitable negative electrical potential.