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 lowermelting-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
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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
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What you will do
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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