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Forging

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Forging&forging process Forging is manufacturing process where metal is pressed, pounded or squeezed under great pressure into high strength parts known as forgings. – PowerPoint PPT presentation

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Title: Forging


1
Forgingforging process
  • Forging is manufacturing process where metal is
    pressed, pounded or squeezed under great pressure
    into high strength parts known as forgings.
  •  

2
The forging process
  • Heated metal to be shaped is placed on a mold.
    Pressure is applied to the metal with the help of
    a press or hammer and due to this impact the
    malleable metal conforms to the
  • die cavity shape.
  • Extreme pressure is produced when the die
    halves are closed. The seam of the die as well as
    punch acts as a relief valve. Once the metal
    object is shaped, flashing is removed
  • Use of a proper lubricant during the process
    helps to prevent sticking of the workpiece with
    the die. It also acts as a thermal insulator and
    helps the wear and tear on the die

3
  • Advantages of Forging
  •            The forgings are consistent in shape
    and do not have any voids, porosity, inclusions,
    or defects.
  • This is especially helpful in later finishing and
    coating operations as surface preparation is
    minimized.
  •            Parts that are produced by this
    method have high strength to weight ratio and
    therefore used in the design of the aircraft
    frames.
  •            It offers low cost for moderate to
    long runs.

4
Different types of Forging processes
  • Open Die Forgings or Hand forgings
    In this process the forgings are made with the
    help of repeated blows in an open die. Here the
    operator manipulates the work piece in the die
    during the blow process, similar to the
    traditional manufacturing process used by a
    blacksmith.

  Impression Die Forgings or Precision Forgings
These forgings are the refined form
of blocker forgings. The finished metal part much
more identical to the die impression.
  • Upset Forgings These forgings
    increase the cross-section by reducing the length
    of the metal. The process is used to make heads
    on valves, bolts and fasteners, and other similar
    parts.

5
Specifications
The process is used on metals with good ductility
such as copper, aluminum, nickel, steel, and
magnesium. Minimizing size, material volume, and
complexity of the design can reduce cost.
6
Example parts Connecting rods, crankshafts,
wrenches, hooks etc.
  • Forging Design Guidelines
  • Avoid undercuts.
  • Recommended external draft 6 degrees (96).
  • Recommended internal draft 8-10 degrees
    (98-100).
  • Provide generous fillet and corner radii to aid
    material flow.
  • Provide support webs and ribs.

7
Once we receives a blueprint, we proceed to make
the master die. A plaster cast is made from the
master die for approval. After the plaster cast
has been approved, the forging dies are made,
using the master die as a pattern
8
  • Bar stock is ordered for the manufacture of the
    forgings. The completed forging dies are then
    mounted in a hammer of sufficient size to form
    the forgings.
  • The bar stock is cut into lengths appropriate to
    the dimensions of the finished forging.The
    lengths of material are heated in a forging
    furnace

9
Each length is pulled from the forging furnace by
the hammerman using tongs, and placed in the
blocker area of the forging die. The hammer is
activated for several blows
10
  • Then, the rough formed forging is moved to the
    finisher area of the forging die. The hammer is
    activated once again for several blows.
  • At this point, the forging is fully formed, but,
    still has a flash attached to it. The flash is
    the excess material around the formed forging.

11
  • The forged piece is removed from the forging
    dies by a trimmerman and is placed in a trim
    press. A few blows are necessary to remove the
    flash from the forging
  • The completed forging is then placed in a
    cooling bin. The cooling bin may contain liquid,
    to comply with the specifications provided on the
    blueprint supplied.

12
  • Once cooled, the forgings are placed in a
    wheelabrator with fine steel shot to clean off
    scale and discoloration formed in the forging
    process

A Forged metal can result in the following
  • Increase length, decrease cross-section, called
    drawing out the metal.
  • Decrease length, increase cross-section, called
    upsetting the metal
  • Change length, change cross-section, by
    squeezing in closed impression dies. This results
    in favorable grain flow for strong parts

13
Cold Forging is a cold working process where the
material is squeezed into a die and the finished
parts assume the shape of the die. This process
is also known as Cold Heading. Bar stock or
wire stock is fed into a die and is squeezed into
the closed die. The resultant part is a nail, a
bolt or a screw with the head. A subsequent
cold heading operation forms other features on
the head such as knurls or slots for screw
drivers etc. the shaping rod stock by forming the
head as in rivets, bolts, nails and other
fasteners. This process can be highly automated
and parts can be made economically.
14
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