STEEL:
Steel making involves melting of iron concentrate at a high temperature of 1700 deg C
with coke. Coke is coal enriched with carbon.Fluxes like limestone and dolomite are added
to react with impurities and separate them out in the form of liquid slag.Sulphur and
phosphorous are impurities which reduce steel strength.
Ship building steel should not have more than 0.05% of these two elements.
Mild steel High tensile steel Cast steel
Carbon 0.21 0.18 0.23 %
Manganese 0.7-1.5 0.9-16 1.6
Silicon 0.1-0.5 0.5 0.6
Sulphur 0.04 0.04 0.05
Phosphorus 0.04 0.04 0.05
Aluminium 0.015 0.015 nil
Approximate density of mild steel 7.84 t/cumtrs
