Oxy fuel gas welding

1. MANUFACTURING
TECHNOLOGY – I
CRAFTED BY:
RAMESH KUMAR A
Assistant Professor
Sona College of Technology
Salem
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2. OXY – FUEL GAS WELDING (OFW)
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3. OXY – FUEL GAS WELDING (OFW)
 “A group of welding processes
which produces coalescence by
heating materials with an oxy fuel
gas flame or flames with or
without the application of
pressure and use of filler metal”
 Four distinct processes
Oxy-acetylene welding
Oxy-hydrogen welding
Air-acetylene welding
Pressure gas welding
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Fuel gases Max Temp
°C
Neutral Temp
°C
Acetylene 3300 3200
Mythyl acetylene propane 2900 2600
Propylene 2860 2500
Propane 2780 2450
methane 2740 2350
Hydrogen 2870 2390

4. OXY – FUEL GAS WELDING (OFW)
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5. OXY – ACETYLENE GAS WELDING (OAW)
 Oxygen gas is produced from commercial liquefaction of air
 The liquid air is allowed to boil and when nitrogen and argon gas escape,
pure liquid oxygen is left
 The gas is compressed in cylinders at a pressure of 15 Mpa
 Acetylene gas is produced by the reaction of calcium carbide with water
CaC2 + 2H2O = C2H2 + Ca (OH)2
 Acetylene gas has the tendency to explode if the pressure is increased
 So the gas is dissolved in acetone (CH3 – CO – CO3) liquid which acts as a
solvent for the gas
 Usually compressed at 1.7 Mpa
 The acetylene cylinder will be packed with porous calcium silicate, so the gas
is absorbed in an effective way
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6. OXY – ACETYLENE GAS WELDING (OAW)
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7. OXY – ACETYLENE GAS WELDING (OAW)
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8. GAS WELDING EQUIPMENTS
 Oxygen cylinder
1550 N/mm^2
Black colour
1.8m^3, 3.5m^3, 7m^3 etc.,
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9. GAS WELDING EQUIPMENTS…
 Acetylene cylinder
175 N/mm^2
marron colour
1.6m^3, 2.8m^3, 8.4m^3 etc.,
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10. GAS WELDING EQUIPMENTS…
 Pressure Regulator
To lower the cylinder pressure to a suitable working operating pressure
To maintain a steady flow of gas under varying cylinder pressure
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11. GAS WELDING EQUIPMENTS…
 Pressure Gauge
Oxygen cylinder (OC) pressure gauge – pressure inside the oxygen cylinder
Oxygen line (OL) pressure gauge – outgoing oxygen pressure through the
house line
Similarly for acetylene AC and AL
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12. GAS WELDING EQUIPMENTS…
 Hoses
 Reinforce flexible rubber hose
 Oxygen – green
 Acetylene - red
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13. GAS WELDING EQUIPMENTS…
 Welding torch
Mixing chamber in which oxygen and acetylene will be mixed and the mixture
is ignited at the torch tip
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14. GAS WELDING EQUIPMENTS…
 Welding tip
Nozzle
Through this narrow section that the mixed gases leave the tourch
Ignited by a spark lighter or a flame lighter
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15. GAS WELDING EQUIPMENTS…
 Other accessories and safety devices
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16. CHARACTERISTICS OF FLAMES
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