The iron pillar was made by instagram in welding of pieces of wrought iron. The resistance of the fuse box for corrosion is the result of a passive protective film at the iron-rust interface. Metal-mail by error, by the traditional method of direct reproduction method, and with a high phosphorus content of 0.25%. The average composition of the steel column is 0.15%of C, 0.05%Mn, 0.05%Ni, 0.03%Cu, 0.25% P, 0.005%, and the remainder iron (fe). The cabinet is resistant to corrosion due to the formation of a thin passive, protective film, it can be said to have a relatively high phosphorus content of the samples. The formation of a smooth, even layer of crystalline iron hydrogen phosphate hydrate, due to the high phosphorus content of the iron will lead to a high level of resistance to corrosion. .
In the presence of iron, the second phase particles (slag and non-reduced (iron oxides) in the microstructure, with high phosphorus content of the metal, and a wide variety of wet and dry atmospheric conditions are the three most important factors in the stages of the formation of a protective passive film.
Ancient Indian blacksmiths do not add lime to their furnaces. The use of limestone as in modern steel production technology, leading to a low phosphorus content, as the greater part of the phosphorus is carried away by the slag. In ancient times, in the absence of lime in the slag and the use of a certain quantity of wood with high phosphorus content (for example, Cassia auriculata), when the melt, leading to a higher phosphorus content (about 25%) than in the most modern equipment is obtained in furnaces (usually less than 0.05%). Wootz steel in India has long been known for its iron and steel. Literature sources indicate that the steel from the South of India, it was rated as one of the best in the world, and that is to be sold in the european, China and the Arab countries and the Middle East. Research on the wootz shows that the high-carbon steel with 1% to 2% of carbon and it is believed to have been used in the making of the Damask knife with a water-steel design. Wootz steel is that it is also a driving force for the development of the modern, metallographic examination, and will also be considered as additional material in modern terminology, because it shows that these steels exhibit superplastic characteristics. This article will describe some of these developments.
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