Oxyacetylene Welding

1

• Oxy-acetylene Welding
• Alternative Name
• Gas welding
• Type of Operation
• Manual
• Heat source
• Fuel-gas flame
• Shielding
• Products of combustion
• Flux for metals other than steel
• Heat input
• Combustion of fuel gas and oxygen
• Mode of operation
• An oxygen and acetylene mixture is burnt at the
  tip of a specially designed nozzle which is
  fitted to a torch body.
• The welder uses the flame to melt the parent
  metal to form a weld pool.
• Filler metal, if required, is added separately by
  manual feeding of a wire into the leading edge of
  the weld pool.
• The welder moves the torch to achieve uniform
  progressive fusion.

Torch
2

• Gas Tungsten Arc Welding (GTAW)
• Alternative Names
• Tungsten inert-gas (TIG) welding WIG welding
• Tungsten arc gas-shielded (TAGS) welding
• Argon arc welding (BOC Ltd. trade name)
• Type of Operation
• Manual
• Heat source
• Arc
• Shielding
• Inert gas
• Current range
• 10 to 300 A
• Heat input
• 0.2 to 8 kJ/s
• Mode of Operation
• An arc is established between the end of a
  tungsten electrode and the parent metal at the
  joint line.
• The electrode is not melted and the welder keeps
  the arc gap constant.

3

• Shielded Metal Arc Welding (SMAW)
• Alternative Names
• Stick-electrode welding
• Electric arc welding
• Manual metal arc welding (MMA)
• Type of operation
• Manual
• Heat Source
• Arc
• Shielding
• Principally flux and some gas generated by flux
• Current Range
• 25 to 350 A
• Heat Input
• 0.5 to 11 kJ/s
• Mode of Operation
• The welder establishes an arc between the end of
  the electrode and the parent metal at the joint
  line.
• The arc melts the parent metal and the electrode
  to form a weld pool which is protected by the
  molten flux layer and gas generated by the flux
  covering of the electrode.

4

• Gas Metal Arc Welding (GMAW)
• Alternative Names
• Metal arc gas-shielded (MAGS) welding
• Metal inert-gas (MIG) welding
• Metal active-gas (MAG) welding
• Semi-automatic welding CO2 welding
• Type of Operation
• Manual, but can be used with a mechanized
  traversing system
• Heat source
• Arc
• Shielding
• Gas, which must not react with the metal being
  welded
• Current range
• 60 to 500 A
• Heat input
• 1 to 25 kJ/s
• Mode of Operation
• An arc is established between the end of the
  electrode and the parent metal at the joint line.
  

5

• Submerged-Arc Welding
• Alternative Names
• None
• Type of Operation
• Mechanized
• Heat Source
• Arc
• Shielding
• Granular flux
• Current Range
• 350 to 2000 A
• Heat Input
• 9 to 80 kJ/s
• Mode of Operation
• An arc is maintained between the end of a bare
  wire electrode and the parent metal.
• The current is controlled by the power-supply
  unit.
• As the electrode is melted, it is fed into the
  arc by a servo-controlled motor.
• This matches the electrode feed rate to the speed
  at which the electrode is melting, thus keeping
  the arc length constant.

6

• Resistance Spot Welding
• Alternative Names
• None
• Type of Operation
• Automatic
• Heat Source
• Resistance heating at an interface
• Shielding
• None required
• Current range
• 100 to 50 000 A
• Heat input
• Mode oOperation
• The work, which is usually in the form of a lap
  joint, is gripped between two copper electrodes.
• A high current at a low voltage flows through the
  parent metal between the electrodes.
• At the interface, heat is generated by the
  resistance offered to the current flow.
• A spot or slug of metal is melted and bridges the
  interface.