MAA-Chap08-Welding Metals
MAA-Chap08-Welding Metals
MAA-Chap08-Welding Metals
Revised 2017
AGRICULTURAL
Introduction
MACHINES
WELDING METALS • Welding is widely used method of joining metal in the fabrication
by
and repair works in the Philippines.
Definitions
Soldering
Welding Processes
• It is the common method of
• Soldering joining metal sheet especially
non-ferrous metal.
• Brazing • Soldering is done at a
• Oxyacetylene Welding relatively low temperature of
427 C compared with other
• Arc Welding methods such as brazing and
arch welding.
• Resistance Welding
• MIG Welding
• TIG Welding
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• In this process, the solder is usually half lead and half tin (50/50). • Flux is used to coat metal prior to welding to remove oxidation
• Heat is supplied either from flame, electric heated soldering gun, or that occurs in the pieces of metal to be joined.
copper metal heated from a blow torch or burner.
• Fluxes are classified as corrosive (acid base) and non-corrosive
• Only clean metal joints can be successfully soldered. (rosin base)
• Requirement for successful soldering work:
– Have a clean well-fitting joint
– Use a well-tinned copper or iron
– Have a an adequate heat so that the metal being soldered will
melt the solder.
– Use proper type and amount of flux.
– Apply the correct amount of solder to the joint.
2
– Regulator – It the special valve
to properly mix the oxygen and
the acetylene gas.
– Hose – This caries the gases
from the cylinder to torch. Read
hose is used for acetylene gas
while the green hose is used for
the oxygen gas.
– Blow pipe or torch
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Indicator of the Quality of Weld Using
Oxyacetylene Welding Equipment
Resistance Welding
• It uses the heat generated by
electric current passing through
a small area of the metal being
joined. The pressure forces
heated the area together until
they have fused.
• Spot welding is the common
form of resistance welding.
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• The two types of electric arc welder
are:
– Alternating current
– Direct Current
• The welding machine can be a motor-
generator type or a transformer type.
5
Welding Joints
• The five basic welding joints are:
– Butt
– Lap
– Tee
– Corner
– Edge
• Welding Beads – This are the lines of metal blobs that look like Welding
string of beads.
Beads
– Thin metals are welded with single string of welding beads or
with a bead on each side of the joints.
– Thick metals are welded by providing a bevel and then weld are
made with several overlapping welding beads. Metal Pieces
Welding Position
• Welding positions includes the
following:
– Flat
– Horizontal
– Vertical
– Overhead
• The flat position is the easiest
and the first to begin with before
doing other positions.
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Automatic Welding Operation
MIG Welding
• The metal inert gas (MIG)
welding – It uses continuous
roll-fed welding rod.
• An inert gas is used to protect
the weld from oxidation. For
steel it uses carbon dioxide
while for aluminum and other
metals, a mixture of argon and
helium is used.
• MIG welding is easier than arc
welding in terms of heat setting,
rate of wire feed, and mixture of
gases.
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TIG Welding
• The tungsten inert gas
welding is widely used for
welding aluminum, stainless
steel and other non-ferrous
metals.
• It is similar to oxyacetylene
welding in that the filler rod is
separate from the torch and
is fed with the opposite hand.
References
• Kazanas H. C. and L. Hannah. Manufacturing Processes: Metals.
Printice-Hall, Inc. Englewood Cliffs, New Jersey. 120pp.
• Repp, V. E. et. al. 1982. Metalwork. Technology and Practice.
McKnight Publishing Company. Bloomington, Illinois. 598pp.
• Scheck, L. A. and G.C. Edmonton. 1976. Practical Welding.
Bruce and Glencde, Inc. London. 150pp
Robotic Welding
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Thank you very much and
God bless!!!
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