INDUSTRIAL SHAPING OF METALS AND ALLOYS

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• Q1: What is the Hot Working Process?
  Ans: Hot working process is a metal forming process in which metal is heated above its recrystallization temperature and then shaped.
  In this process, the metal becomes soft and can be easily deformed without breaking.
• Q2: State the advantages of the Hot Working Process.
  Ans: The advantages are:

  • ➔ Improves strength and toughness of metal
  • ➔ Removes internal stresses
  • ➔ Refines grain structure
  • ➔ Large deformation is possible
  • ➔ No cracks are formed easily
• Q3: State the methods of Hot Working.
  Ans: The methods of hot working are:

  • ➔ Rolling
  • ➔ Forging
  • ➔ Extrusion
  • ➔ Piercing
  • ➔ Cupping
• Q4: Briefly explain the process of Hot Rolling.
  Ans: In hot rolling, heated metal is passed between rotating rollers.
  The rollers reduce the thickness and change the shape of the metal.
  This process is used to make sheets, plates, and rods.
• Q5: Briefly explain the process of Forging.
  Ans: Forging is a process in which heated metal is shaped by applying compressive force using hammer or press.
  It improves the strength and structure of the metal.
• Q6: Briefly explain the process of Extrusion.
  Ans: Extrusion is a process in which heated metal is forced through a die opening.
  The metal takes the shape of the die and forms long objects like rods and tubes.
• Q7: Briefly explain the process of Piercing.
  Ans: Piercing is a process used to make holes in hot metal.
  A pointed tool is pushed into the metal to create a hollow shape.
• Q8: Briefly explain the process of Cupping.
  Ans: Cupping is a process in which a flat metal sheet is converted into a cup shape.
  This is done by pressing the metal into a die using a punch.
• Q9: What is a Two High Reversing Mill?
  Ans: A two high reversing mill has two rollers.
  The direction of rotation of rollers can be reversed to pass the metal back and forth for reduction.
• Q10: What is a Three High Mill?
  Ans: A three high mill has three rollers placed one above the other.
  Metal passes in one direction between one pair and returns through the other pair without reversing the rollers.
• Q11: What is a Four High Mill?
  Ans: A four high mill has four rollers.
  Two small rollers are used for rolling and two large rollers support them to provide strength and reduce bending.
• Q12: What is a Continuous Mill?
  Ans: A continuous mill consists of a series of rolling stands.
  The metal passes through each stand continuously to reduce thickness step by step.
• Q13: Briefly explain the manufacturing of Seamless Pipes.
  Ans: Seamless pipes are made from solid round billets.
  The billet is heated and pierced to form a hollow tube.
  Then it is rolled and stretched to get the required size without any joint or seam.
• Q14: State some Forging operations.
  Ans: Some forging operations are:

  • ➔ Drawing out
  • ➔ Upsetting
  • ➔ Bending
  • ➔ Punching
  • ➔ Swaging
• Q15: What is Drop Forging?
  Ans: Drop forging is a forging process in which a hammer is dropped on heated metal placed in a die.
  The metal takes the shape of the die cavity.
• Q16: Name the hammers used for Drop Forging.
  Ans: The hammers used are:

  • ➔ Gravity drop hammer
  • ➔ Power drop hammer
• Q17: What is Upsetting Forging?
  Ans: Upsetting forging is a process in which the length of metal is reduced and its diameter is increased by compressive force.
• Q18: What is a Pneumatic Hammer?
  Ans: A pneumatic hammer is a machine that uses compressed air to move the hammer.
  It is used to apply force in forging operations.
• Q19: Briefly explain the process of Backward Extrusion.
  Ans: In backward extrusion, the metal flows in the opposite direction of the applied force.
  The punch moves into the metal, and the metal flows backward around the punch to form a hollow shape.
• Q20: Briefly explain the process of Tube extrusion.
  Ans: Tube extrusion is used to produce hollow tubes.
  A mandrel is placed inside the die, and metal is forced through it to form a tube shape.
• Q21: What is the Cold Working Process?
  Ans: Cold working process is a metal forming process done at room temperature or below recrystallization temperature.
  In this process, metal is shaped without heating, which increases its strength and hardness.
• Q22: State the methods of Cold Working.
  Ans: The methods of cold working are:

  • ➔ Cold Rolling
  • ➔ Cold Forging
  • ➔ Cold Extrusion
  • ➔ Drawing
  • ➔ Pressing
• Q23: State the advantages of the Cold Rolling Process.
  Ans: The advantages are:

  • ➔ Better surface finish
  • ➔ Accurate dimensions
  • ➔ Increased strength and hardness
  • ➔ No heating cost
  • ➔ Good mechanical properties
• Q24: State the names of Cold Rolling Mills.
  Ans: The types of cold rolling mills are:

  • ➔ Sendzimir Mill
  • ➔ Saxl Pendulum Mill
• Q25: Briefly explain the Sendzimir Mill.
  Ans: Sendzimir mill is a type of cold rolling mill with multiple small rollers.
  It is used for rolling thin sheets with high accuracy and smooth surface finish.
• Q26: Briefly explain the Saxl Pendulum Mill.
  Ans: Saxl pendulum mill uses a swinging (pendulum) motion of rolls.
  It reduces thickness in small steps and is suitable for precise rolling work.
• Q27: What is Cold Forging?
  Ans: Cold forging is the process of shaping metal at room temperature using compressive force.
  It improves strength due to strain hardening.
• Q28: What is Cold Pressing?
  Ans: Cold pressing is a process in which metal is shaped by applying pressure without heating.
  It is commonly used to form sheets into desired shapes.
• Q29: What is Coining?
  Ans: Coining is a cold working process used to produce fine details on metal surfaces.
  High pressure is applied to get exact shape and smooth finish, like coins.
• Q30: What is Thread Forming?
  Ans: Thread forming is a process of producing threads on a rod by plastic deformation.
  No material is removed; instead, it is displaced to form threads.
• Q31: What is a Die Machine? Name some.
  Ans: A die machine is used to form threads or shapes on metal using dies.
  Some types are:

  • ➔ Rotary Planetary Machine
  • ➔ Cylindrical Die Machine
  • ➔ Reciprocating Flat Die Machine
• Q32: Briefly explain the Rotary Planetary Machine.
  Ans: In this machine, rotating dies move around the workpiece.
  It is used for high-speed thread rolling and shaping operations.
• Q33: Briefly explain the Cylindrical Die Machine.
  Ans: Cylindrical die machine uses round dies to form threads on cylindrical rods.
  The dies rotate and press the material to form threads.
• Q34: Briefly explain the Reciprocating Flat Die Machine.
  Ans: This machine uses two flat dies, one fixed and one moving back and forth.
  The moving die presses the workpiece to form threads.
• Q35: Name the methods of manufacturing of Pipes.
  Ans: The methods are:

  • ➔ Rolling and extrusion (seamless pipes)
  • ➔ Fabrication (welded pipes)
  • ➔ Casting
• Q36: Name the methods of manufacturing of Pipes by Fabrication.
  Ans: The methods are:

  • ➔ Butt welded pipes
  • ➔ Lap welded pipes
• Q37: What are Butt Welded Pipes?
  Ans: Butt welded pipes are made by joining the edges of metal sheets directly edge to edge.
  The edges are welded together to form a pipe.
• Q38: What are Lap Welded Pipes?
  Ans: Lap welded pipes are made by overlapping the edges of metal sheets.
  The overlapped edges are then welded to form a pipe.
• Q39: Name the methods of manufacturing of Pipes by Casting.
  Ans: The methods are:

  • ➔ Centrifugal Casting
  • ➔ Sand Casting
• Q40: What is Centrifugal Casting?
  Ans: Centrifugal casting is a process in which molten metal is poured into a rotating mould.
  The rotation forces the metal to spread and form a hollow pipe shape.
• Q41: What is Sand Casting?
  Ans: Sand casting is a process in which molten metal is poured into a sand mould.
  After solidification, the mould is broken to get the casting.
• Q42: What is the process of Piercing?
  Ans: Piercing is a process of making a hole in metal without removing material.
  A tool is forced into the metal to create a hollow or opening.