WELDING OF FERROUS & NON-FERROUS METALS

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• Q1: Define Ferrous Metals. Name some.
  Ans: Ferrous metals are metals that contain iron as their main element.
  Some examples are:

  • ➔ Steel
  • ➔ Cast Iron
  • ➔ Wrought Iron
• Q2: Define Non-Ferrous Metals. Name some.
  Ans: Non-ferrous metals are metals that do not contain iron.
  Some examples are:

  • ➔ Aluminium
  • ➔ Copper
  • ➔ Zinc
  • ➔ Lead
• Q3: Briefly explain the welding of Ferrous Metals.
  Ans: Welding of ferrous metals is generally easier because they contain iron and have good weldability.
  However, proper temperature control is required to avoid cracks and distortion.
• Q4: Briefly explain the welding of Non-Ferrous Metals.
  Ans: Welding of non-ferrous metals is more difficult because they have lower melting points and high thermal conductivity.
  Special techniques and care are required to avoid defects.
• Q5: What is Pre-heating?
  Ans: Pre-heating is the process of heating the metal before welding to a specific temperature to improve weld quality.
• Q6: State the methods of Pre-heating.
  Ans: The methods of pre-heating are:

  • ➔ Blow pipe flame heating
  • ➔ Electrical heating
  • ➔ Furnace heating
  • ➔ Mechanical heating
• Q7: State any two purposes of Pre-heating.
  Ans: The purposes are:

  • ➔ To reduce cracking in welds
  • ➔ To improve weld strength
• Q8: Briefly explain Preheating with Blow Pipe Flame.
  Ans: In this method, a blow pipe flame is used to heat the metal surface before welding.
  It is simple and commonly used for small jobs.
• Q9: What is Peening?
  Ans: Peening is a process of hammering the welded metal to relieve internal stresses and improve strength.
• Q10: Briefly explain the method of Peening.
  Ans: In peening, the weld is lightly hammered while it is still hot.
  This helps to reduce stress and prevent cracks.
• Q11: What is Spot Heating?
  Ans: Spot heating is a process of heating a small specific area of metal to control distortion or relieve stress.
• Q12: Briefly explain the method of Spot Heating.
  Ans: In spot heating, heat is applied to a small area using a flame.
  The heated area expands and helps in correcting distortion.
• Q13: Briefly explain the mechanical method of preheating.
  Ans: In the mechanical method, heat is generated by mechanical means such as friction or external devices.
  It is used when uniform heating is required.
• Q14: Briefly explain Welding of Cast Iron.
  Ans: Welding of cast iron is difficult due to its brittle nature and high carbon content.
  Pre-heating and slow cooling are required to avoid cracks.
• Q15: What is Cast Iron?
  Ans: Cast iron is a ferrous metal that contains a high percentage of carbon, making it hard and brittle.
• Q16: What is Grey Cast Iron?
  Ans: Grey cast iron is a type of cast iron that has graphite flakes in its structure, giving it a grey appearance and good machinability.
• Q17: What is Welding Flux?
  Ans: Welding flux is a chemical substance used during welding to prevent oxidation and remove impurities from the weld area.
• Q18: What is a Gas Welding Rod?
  Ans: A gas welding rod is a filler metal used in gas welding to join two metal pieces together.
• Q19: What is Flux?
  Ans: Flux is a chemical substance used to clean and protect metal surfaces during welding or soldering.
  It prevents oxidation and helps in smooth joining of metals.
• Q20: What is Welding Flux?
  Ans: Welding flux is a material used during welding to remove oxides and impurities from the metal surface and protect the weld from atmospheric contamination.
• Q21: Name the flux used in the Welding of Aluminium?
  Ans: The flux used in aluminium welding is:

  • ➔ Aluminium oxide flux
• Q22: What is Welding?
  Ans: Welding is a process of joining two or more metal parts by heating them to a suitable temperature with or without pressure and filler material.
• Q23: State the procedure of Welding.
  Ans: The welding procedure is as follows:

  • ➔ Clean the metal surface
  • ➔ Set the welding equipment
  • ➔ Strike the arc or ignite the flame
  • ➔ Melt the base metal and filler rod
  • ➔ Form the weld joint
  • ➔ Allow it to cool properly
• Q24: Briefly explain the welding of Aluminium and its alloys.
  Ans: Welding of aluminium and its alloys is difficult because of oxide layer and high thermal conductivity.
  Proper cleaning, correct flux, and controlled heat are required to get a good weld.
• Q25: What is TIG Welding?
  Ans: TIG welding (Tungsten Inert Gas welding) is a process that uses a non-consumable tungsten electrode and inert gas to produce a clean and strong weld.
• Q26: What is MIG Welding?
  Ans: MIG welding (Metal Inert Gas welding) is a process that uses a consumable wire electrode and shielding gas to join metals.
• Q27: State any two uses of Filler Rod.
  Ans: The uses are:

  • ➔ To fill the gap between metal parts
  • ➔ To strengthen the weld joint
• Q28: Briefly explain the welding of Copper.
  Ans: Welding of copper is difficult due to its high thermal conductivity.
  Pre-heating and proper flux are required to avoid heat loss and ensure a strong weld.
• Q29: State any four properties of Copper.
  Ans: The properties are:

  • ➔ High electrical conductivity
  • ➔ High thermal conductivity
  • ➔ Good corrosion resistance
  • ➔ Ductile and malleable
• Q30: State the methods used for the welding of Copper.
  Ans: The methods are:

  • ➔ Gas welding
  • ➔ Arc welding
  • ➔ TIG welding
  • ➔ MIG welding
• Q31: Briefly explain the construction of TIG Welding Machine.
  Ans: A TIG welding machine consists of a power source, torch, electrode, shielding gas supply, and control unit.
  It is designed to produce a stable arc using a tungsten electrode.
• Q32: State the parts of TIG Welding Machine.
  Ans: The parts are:

  • ➔ Power supply
  • ➔ Tungsten electrode
  • ➔ Torch
  • ➔ Gas cylinder
  • ➔ Regulator
  • ➔ Work clamp
• Q33: State any four advantages of TIG Welding.
  Ans: The advantages are:

  • ➔ High quality weld
  • ➔ Clean and neat appearance
  • ➔ No slag formation
  • ➔ Suitable for thin materials
• Q34: State the disadvantages of TIG Welding.
  Ans: The disadvantages are:

  • ➔ High cost of equipment
  • ➔ Requires skilled operator
  • ➔ Slower process
  • ➔ Not suitable for thick metals
• Q35: What are TIG Torches?
  Ans: TIG torches are tools used in TIG welding to hold the tungsten electrode and supply shielding gas to the welding area.
• Q36: State the parts of TIG Torches.
  Ans: The parts of TIG torches are:

  • ➔ Tungsten electrode
  • ➔ Nozzle
  • ➔ Collet
  • ➔ Gas lens
  • ➔ Torch body
• Q37: State the types of TIG Welding Torches.
  Ans: The types are:

  • ➔ Air-cooled torch
  • ➔ Water-cooled torch
• Q38: What is a TIG Unit?
  Ans: A TIG unit is a complete welding system that includes power supply, torch, gas supply, and control system used for TIG welding.
• Q39: What is Argon Gas?
  Ans: Argon gas is an inert gas used in welding to protect the weld area from atmospheric contamination.
• Q40: State the functions of Argon Gas.
  Ans: The functions are:

  • ➔ Protects the weld from air
  • ➔ Prevents oxidation
  • ➔ Stabilizes the arc
  • ➔ Improves weld quality
• Q41: What is a Shielding Gas Cylinder?
  Ans: A shielding gas cylinder is a container used to store and supply protective gases like argon during welding.
• Q42: What is Current Adjustment in TIG Welding?
  Ans: Current adjustment in TIG welding is the process of setting the required current level to control heat and weld quality.
• Q43: What is a GMAW?
  Ans: GMAW (Gas Metal Arc Welding) is a welding process in which a consumable wire electrode and shielding gas are used to join metals.
  It is also known as MIG welding.
• Q44: State the components of GMAW Equipment.
  Ans: The components are:

  • ➔ Power source
  • ➔ Wire feeder
  • ➔ Welding gun
  • ➔ Gas cylinder
  • ➔ Control unit
• Q45: What is a Welding Gun?
  Ans: A welding gun is a device used in MIG welding to feed the electrode wire and direct the shielding gas to the weld area.
• Q46: State the parts of a Welding Gun.
  Ans: The parts are:

  • ➔ Nozzle
  • ➔ Contact tip
  • ➔ Trigger
  • ➔ Gas diffuser
  • ➔ Cable
• Q47: Name some Shielding gases.
  Ans: Some shielding gases are:

  • ➔ Argon
  • ➔ Helium
  • ➔ Carbon dioxide (CO₂)
  • ➔ Oxygen
• Q48: Name the gas used for welding Mild Steel.
  Ans: The gas commonly used for welding mild steel is:

  • ➔ Carbon dioxide (CO₂)
• Q49: What is Arc of MIG Welding?
  Ans: The arc of MIG welding is an electric arc formed between the wire electrode and the workpiece, which produces heat to melt the metal.
• Q50: What is Current Adjustment in MIG Welding?
  Ans: Current adjustment in MIG welding is the setting of current level to control penetration, heat input, and weld quality.
• Q51: State any four advantages of MIG Welding.
  Ans: The advantages are:

  • ➔ High welding speed
  • ➔ Easy to operate
  • ➔ Less spatter
  • ➔ Good weld quality
• Q52: State the disadvantages of MIG Welding.
  Ans: The disadvantages are:

  • ➔ Equipment is costly
  • ➔ Not suitable for outdoor use (wind affects gas)
  • ➔ Requires shielding gas
  • ➔ Less portable