Conclusions : In conclusion we can say, other than the massive structure, Delhi's climate, protective layer of phosphate film formation etc that contribute to corrosion resistance, the microstructures (finer grain size, two phase like structure, effect of alloying elements and hot forging) at various locations play a critical role. The chemical composition i e, austenite stabilizing minor elements are beautifully selected/ tailored to improve corrosion resistance. May be this is the prime contributor for corrosion resistance, since similar ancient iron beams kept in the humid environments (16) also have not corroded. This supports our understanding, that austenite stabilizing elements and the higher 'P' content are the major contributors for corrosion resistance of ancient steels. The alloying elements and thermo-mechanical treatments are tailored/defined in the ancient iron beams, such that it is corrosion resistant.
展开▼
