Oxy fuel gas welding

Oxy fuel gas welding

1. MANUFACTURING TECHNOLOGY – I CRAFTED BY: RAMESH KUMAR A Assistant Professor Sona College of Technology Salem 07-02-2018 13:24 1

2. OXY – FUEL GAS WELDING (OFW) 07-02-2018 13:24 2

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 07-02-2018 13:24 3 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) 07-02-2018 13:24 4

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 07-02-2018 13:24 5

6. OXY – ACETYLENE GAS WELDING (OAW) 07-02-2018 13:24 6

7. OXY – ACETYLENE GAS WELDING (OAW) 07-02-2018 13:24 7

8. GAS WELDING EQUIPMENTS Oxygen cylinder 1550 N/mm^2 Black colour 1.8m^3, 3.5m^3, 7m^3 etc., 07-02-2018 13:24 8

9. GAS WELDING EQUIPMENTS… Acetylene cylinder 175 N/mm^2 marron colour 1.6m^3, 2.8m^3, 8.4m^3 etc., 07-02-2018 13:24 9

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 07-02-2018 13:24 10

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 07-02-2018 13:24 11

12. GAS WELDING EQUIPMENTS… Hoses Reinforce flexible rubber hose Oxygen – green Acetylene - red 07-02-2018 13:24 12

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 07-02-2018 13:24 13

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 07-02-2018 13:24 14

15. GAS WELDING EQUIPMENTS… Other accessories and safety devices 07-02-2018 13:24 15

16. CHARACTERISTICS OF FLAMES 07-02-2018 13:24 16