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Welding

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					  Welding


After the lesson students will be able to
  identify different forms, understand
   techniques, and safety of welding
What is it?
A fabrication or sculptural process that joins
  materials, usually metals, to become one.
How is it done?
                  Often done by melting the
                    work pieces and
                    adding a filler material
                    to form a pool of
                    molten material (the
                    weld pool) that cools to
                    become a strong joint.
                  Pressure sometimes
                    used in conjunction
                    with heat, or by itself, to
                    produce the weld.
What is similar to welding?
Soldering and brazing,
  which involve
  melting a lower-
  melting-point
  material between the
  work pieces to form
  a bond between
  them, without
  melting the work
  pieces.
What can be used for welding?
Many different energy sources can be used for welding,
  including:
 Gas flame
 Electric arc: An electrical breakdown of a gas which produces ongoing plasma,
   resulting from a current flowing through normally a nonconductive media such as air.

 Laser
 Electron beam:              A beam of high-velocity electrons applied to materials being
   joined.

 Friction:     Generates heat through mechanical friction between a moving work
   piece and a stationary component, with the addition of a lateral force called
   "upset" to plastically displace and fuse the materials.

 Ultrasound:
   Where can welding be done?
While often an industrial process, welding can be
 done in many different environments, including
 open air, underwater and in outer space.
History of Welding

              Welding was used in the
               construction of the iron
               pillar in Delhi India,
               erected about 310 AD
               and weighing 5.4 metric
               tons.
History of welding
Until the end of the 19th century, the only
  welding process was forge welding, which
  blacksmiths had used for centuries to join iron
  and steel by heating and hammering them.
Arc welding and oxyfuel welding were among
  the first processes to develop late in the
  century, and resistance welding followed
  soon after.
History of welding
Welding, was transformed during the 19th century. In
  1802, Russian scientist Vasily Petrov discovered the
  electric arc and subsequently proposed its possible
  practical applications, including welding.
From this many other forms, including current forms,
  have been born including:
 Carbon arc welding
 Alternating current welding
 Resistance welding
 Oxyfuel welding
 History of welding
World War I and
World War II
caused a major
surge in the use of
welding processes,
with the various
military powers
attempting to
determine which of
the several new
welding processes
would be best.
Processes
   Forge welding
   Shielded metal arc welding
   Gas metal arc welding
   Flux-cored arc welding
   Gas tungsten arc welding
   Plasma arc welding
   Submerged arc welding
   Oxyfuel welding
   Resistance welding
   Spot welding and Seam welding
   Laser beam welding, Electron beam welding, and X-ray welding
   Explosion welding
What you will do
1st hour: choose a process
2nd and 4th hour : find a partner and choose a
 process
Research process on internet
     What is it
     History
     How it is used/done
     What is used
     All of important information
What you will do
    Make a Power Point of at least 10 slides (have
     information, pictures, etc to present)
    Make all information relative/easy to follow
    Make a “notes” sheet on your process on a
     word document for students to follow along
     with, similar to the one I gave for my Power
     Point

				
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posted:3/26/2012
language:English
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