STEEL MANUFACTURING PROCESSES

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• Q1: Define Steel.
  Ans: Steel is an alloy of iron and carbon.
  It contains a small percentage of carbon and is stronger than iron.
• Q2: What is the percentage of Carbon in steel?
  Ans: Steel contains about 0.1% to 1.5% carbon.
• Q3: Write the composition of Steel.
  Ans: The composition of steel is:

  • ➔ Iron (Fe): 98% to 99%
  • ➔ Carbon (C): 0.1% to 1.5%
  • ➔ Small amounts of manganese, silicon, sulfur, and phosphorus
• Q4: State the properties of Steel.
  Ans: The properties are:

  • ➔ High strength
  • ➔ Good hardness
  • ➔ Ductile and malleable (depending on type)
  • ➔ Can be heat treated
  • ➔ Good machinability
• Q5: State the uses of Steel.
  Ans: The uses are:

  • ➔ Construction of buildings and bridges
  • ➔ Automobile industry
  • ➔ Machinery and tools
  • ➔ Railway tracks
• Q6: What is the annual production of steel in the world?
  Ans: The world annual steel production is approximately 1.8 to 2.0 billion tons.
• Q7: State the types of Steel.
  Ans: The types are:

  • ➔ Plain Carbon Steel
  • ➔ Alloy Steel
• Q8: What is Plain Carbon Steel?
  Ans: Plain carbon steel is steel that contains only iron and carbon as main elements.
  It has no significant alloying elements.
• Q9: What is Alloy Steel?
  Ans: Alloy steel is steel that contains additional elements like chromium, nickel, or manganese
  to improve its properties.
• Q10: What is the Acid Process of making Steel?
  Ans: The acid process uses acidic lining in the furnace.
  It removes impurities like manganese and phosphorus only in limited amount.
• Q11: What is the Basic Process of making Steel?
  Ans: The basic process uses basic lining (like lime).
  It removes acidic impurities such as phosphorus and sulfur effectively.
• Q12: Name the raw materials used for Steel Manufacturing.
  Ans: The raw materials are:

  • ➔ Pig iron
  • ➔ Scrap iron
  • ➔ Limestone
  • ➔ Iron ore
• Q13: Name the processes used for making steel.
  Ans: The processes are:

  • ➔ Cementation process
  • ➔ Crucible process
  • ➔ Open hearth process
  • ➔ Bessemer process
  • ➔ Duplex process
  • ➔ Electric arc process
  • ➔ L-D process
• Q14: Briefly explain the process of Cementation.
  Ans: Cementation is a process in which wrought iron is heated with carbon materials.
  Carbon diffuses into iron and converts it into steel.
• Q15: Briefly explain the Crucible process of making steel.
  Ans: In the crucible process, small pieces of iron are melted in a crucible with carbon.
  It produces high-quality steel.
• Q16: Briefly explain the Open Hearth process of making steel.
  Ans: In this process, pig iron and scrap are melted in a large open hearth furnace.
  Impurities are removed by oxidation and slag formation.
• Q17: Briefly explain the Bessemer process of making steel.
  Ans: In the Bessemer process, hot air is blown through molten pig iron.
  Carbon and impurities are oxidized and removed quickly.
• Q18: Briefly explain the Duplex process of making steel.
  Ans: The duplex process combines two methods, usually Bessemer and open hearth.
  It improves efficiency and steel quality.
• Q19: Briefly explain the Electric Arc process of making steel.
  Ans: In this process, an electric arc is used to melt scrap steel.
  It produces high-quality steel with precise control.
• Q20: Briefly explain the L-D process of making steel.
  Ans: The L-D (Linz-Donawitz) process uses pure oxygen blown into molten iron.
  It quickly removes carbon and impurities.
• Q21: State the chemical reactions taking place in steel making furnaces.
  Ans: The main reactions are:

  • ➔ C + O₂ → CO₂
  • ➔ CO₂ + C → 2CO
  • ➔ FeO + C → Fe + CO
• Q22: Briefly explain the construction of Open Hearth Furnace.
  Ans: The open hearth furnace is a large rectangular furnace made of steel and refractory bricks.
  It has a shallow hearth, roof, regenerators, and charging doors.
  The roof reflects heat onto the metal for melting and refining.
• Q23: Name the parts of Open Hearth Process.
  Ans: The parts are:

  • ➔ Hearth
  • ➔ Roof
  • ➔ Regenerators
  • ➔ Charging doors
  • ➔ Gas and air ports
• Q24: Name the fuels used for Open Hearth Furnace.
  Ans: The fuels used are:

  • ➔ Producer gas
  • ➔ Natural gas
  • ➔ Oil (in some cases)
• Q25: What is the quantity of Steel obtained through Open Hearth Furnace?
  Ans: The open hearth furnace can produce about 50 to 500 tons of steel per heat (batch), depending on size.
• Q26: State the reactions of Acid Bessemer Process.
  Ans: The main reactions are:

  • ➔ C + O₂ → CO₂
  • ➔ Mn + O → MnO
  • ➔ Si + O₂ → SiO₂

  In acid process, phosphorus and sulfur are not removed effectively.
• Q27: State the advantages of L-D Process.
  Ans: The advantages are:

  • ➔ Very fast steel production
  • ➔ High quality steel
  • ➔ Low fuel consumption
  • ➔ Easy control of composition
• Q28: State the advantages of an Electric Arc Furnace.
  Ans: The advantages are:

  • ➔ Produces high-quality steel
  • ➔ Suitable for all types of steel
  • ➔ Precise temperature control
  • ➔ Uses scrap steel efficiently
• Q29: State the parts of an Electric Arc Furnace.
  Ans: The parts are:

  • ➔ Electrodes
  • ➔ Furnace shell
  • ➔ Hearth
  • ➔ Roof
  • ➔ Charging door
• Q30: State the types of an Electric Arc Furnace.
  Ans: The types are:

  • ➔ Direct arc furnace
  • ➔ Indirect arc furnace
• Q31: Briefly explain the construction of an indirect Electric Arc Furnace.
  Ans: In an indirect electric arc furnace, the arc is formed between two electrodes and not directly on the metal.
  Heat is radiated to melt the charge placed in the hearth.
  It is used for small-scale production.
• Q32: What is Lime Boil?
  Ans: Lime boil is the reaction of lime (CaO) with impurities during steel making.
  It helps in forming slag and removing impurities.
• Q33: What is Ore Boil?
  Ans: Ore boil is the reaction of iron ore with carbon monoxide or oxygen.
  It helps in removing impurities during steel making.
• Q34: What is Spiegeleisen
  Ans: Spiegeleisen is an alloy of iron, manganese, and carbon.
  It is added to molten steel to increase carbon and manganese content.
• Q35: What is Ferro Manganese?
  Ans: Ferro manganese is an alloy of iron and manganese.
  It is used to improve strength, hardness, and wear resistance of steel.