Friday, September 13, 2019
Steel making Essay Example | Topics and Well Written Essays - 1500 words
Steel making - Essay Example ed in the air blown through molten pig iron burned off its impurities such as carbon and silicon, in exothermic reactions fueling the process, enabling the production of commercial grade steel at affordable costs(Cottrell,131). Siemens and Martin invented the Open Hearth Process around 1865 which is still surviving to this day. To cut a long story short, these early steel making processes have now been made almost obsolescent over the years, by the rapid advancements made in thermodynamics, electrical engineering, metallurgy, extractive metallurgy and computer and information technology which have transformed the art of steelmaking into quite modern day steel making processes such as the Basic Oxygen Steelmaking (BOS) Process and the Electric Arc Furnace (EAF) Process. While the steel industry has thus undergone gradual but sweeping changes over time, most of the current processes of steel making still involve producing steel from either pig iron or from a mixture of pig iron and ste el scrap. All steel making processes deal with the removal of excessive impurities from the melt by means of slag formation in the furnace. The impurities are removed by formation of either an acid slag or a basic slag. The acid or siliceous slag removes the impurities silicon, manganese and carbon by oxidation and also enables the addition of alloying elements such as nickel, chromium, manganese vanadium, molybdenum, tungsten, niobium and titanium as ferroalloys for purposes of alloy steel making. The basic or limey slag removes the impurities phosphorous and sulfur in addition to silicon, manganese and carbon in the bath of metal which is oxidized to a greater extent than in acid process. The carbon present as the alloying element in iron matrix imparts to it a reduction in ductility but causes considerable increase in strength. Besides, the alloyed carbon in steel is responsible for various other properties of the steel: its property of getting hardened when subjected to
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