Seminar On Gas Welding – Seminar report pdf Download
Welding is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone, and with or without the use of filler material.
Welding is used for making permanent joints. It is used in the manufacture of automobile bodies, aircraft frames, railway wagons, machine frames, structural works, tanks, furniture, boilers, general repair work and ship building.
TYPES OF WELDING :
· Plastic Welding or Pressure Welding
The piece of metal to be joined are heated to a plastic state and forced together by external pressure (Ex) Resistance welding
· Fusion Welding or Non-Pressure Welding
The material at the joint is heated to a molten state and allowed to solidify (Ex) Gas welding, Arc welding
In gas welding, a gas flame is used to melt the edges of metals to be joined. The flame is produced at the tip of welding torch. Oxygen and Acetylene are the gases used to produce the welding flame. The flame will only melt the metal. A flux is used during welting to prevent
oxidations and to remove impurities. Metals 2 mm to 50 mm thick are welded by gas welding. The temperature of oxyacetylene flame is about 3200°c. Fig shows Gas welding equipments.
Gas Welding Equipment
1. Gas Cylinders
Oxygen – 125 kg/cm2
Acetylene – 16 kg/cm2
Working pressure of oxygen 1 kg/cm2
Working pressure of acetylene 0.15 kg/cm2
Working pressure varies depends upon the thickness of the work pieces welded.
3. Pressure Gauges
5. Welding torch
6. Check valve
7. Non return valve
TYPES OF FLAMES
• When acetylene is burned in air, it produces a yellow sooty flame, which is not enough for welding applications
• Oxygen is turned on, flame immediately changes into a long white inner area (Feather) surrounded by a transparent blue envelope is called Carburizing flame (30000c)
• This flames are used for hardening the surfaces
• Addition of little more oxygen give a bright whitish cone surrounded by the transparent blue envelope is called Neutral flame (It has a balance of fuel gas and oxygen)
• Most commonly used flame because it has temperature about 32000c
• Used for welding steels, aluminium, copper and cast iron
• If more oxygen is added, the cone becomes darker and more pointed, while the envelope becomes shorter and more fierce is called Oxidizing flame
• Has the highest temperature about 34000c
• Used for welding brass and brazing operation
Advantages Of gas welding
1. Equipment has versatile
2. Same equipment can be used for oxyacetylene cutting and brazing by varying the torch size
3. Heat can controlled easily
Disadvantages of gas welding
1. Slower process
2. Risk is involved in handling gas cylinders
Report Download :
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