Corrosion in History
Interest in the corrosion problem has been increasing for many years. This has inspired investigators and writers to such an extent that it is now difficult to follow the voluminous technical literature relating to this subject and select that which is useful. The wastage of metals due to corrosion has become an important engineering problem. Probably no other source of waste, except that affecting human life, is of greater concern to all. Hoover has well said:(reference: Speller, 1935)
"It is only through the elimination of waste and the increase in our national efficiency that we can hope to lower the cost of living, on the one hand, and raise our standards of living, on the other. The elimination of waste is a total asset. It has no liabilities".
An accurate estimate of the loss resulting from corrosion of iron and steel is, of course, out of the question. From certain data, however, which are at hand regarding the average annual renewal of corrugated metal roofing, wire, pipe lines, steel coal cars, and similar iron and steel products often subject to severe corrosion, it seems that, because of inadequate protection, the annual replacement from this cause, on the average, may reach as much as 2 per cent of the total tonnage in use. It is estimated that about 1,200,000,000 long tons of rolled iron and steel products were in use in the world in 1931.
In recent years the steel produced was about eighteen times the total tonnage of all non-ferrous metals. On this basis, it is evident that a large and increasing proportion of the annual production may be required to replace that rendered unserviceable by corrosion. It is true that a large part of the corroded metal is recovered as scrap, but, on the other hand, in structures where the metal is not readily accessible the total cost incidental to replacement is often many times the cost of the new material required. Sometimes the reduction in sectional area and strength of structural iron and steel, due to corrosion, leads to serious weakening or failure.