Welding Hand Tools
Welding hand tools are used to assist in various welding operations such as cleaning, removing slag, shaping metal, and holding workpieces. These tools help improve the quality and efficiency of welding work.
Common Welding Hand Tools
- Chipping Hammer: Used to remove slag from welded joints after welding.
- Ball Peen Hammer: Used for shaping metal and assisting in welding operations.
- Wire Brush: Used for cleaning the weld area before and after welding.
- Tongs: Used to hold hot metal pieces safely.
- Clamps: Used to hold workpieces firmly during welding.
Carbon Dioxide Welding
Carbon dioxide welding, commonly known as CO₂ welding, is a type of gas metal arc welding (GMAW). In this process, carbon dioxide gas is used as a shielding gas to protect the weld area from atmospheric contamination.
Description
In CO₂ welding, a continuous wire electrode is fed automatically through a welding gun. An electric arc forms between the electrode and the workpiece, melting the metal and forming the weld joint.
Principle
The process works on the principle of electric arc generation between the electrode wire and the base metal. The carbon dioxide gas shields the molten weld pool from oxygen and nitrogen in the air.
Method of Operation
- Clean the metal surface to be welded.
- Set the welding current and voltage.
- Start the flow of CO₂ shielding gas.
- Feed the electrode wire through the welding gun.
- Create an electric arc between the wire and the workpiece.
- Move the welding gun along the joint to complete the weld.
High Pressure (H.P.) Welding Equipment
Description
High pressure welding equipment uses oxygen and fuel gases stored at high pressure in cylinders. The gases are supplied through regulators and hoses to the welding torch where combustion produces a high-temperature flame.
Principle
The process works on the principle of mixing oxygen and fuel gas in correct proportions to produce a high-temperature flame capable of melting metals.
Method of Operation
- Open the gas cylinders and set the regulators.
- Check hoses and connections for leaks.
- Mix oxygen and fuel gas in the torch.
- Ignite the gas mixture using a spark lighter.
- Adjust the flame and start welding.
Low Pressure (L.P.) Welding Equipment
Description
Low pressure welding equipment is commonly used with acetylene generators that produce gas at low pressure. The gas is supplied directly to the welding torch.
Principle
The welding flame is produced by burning a mixture of oxygen and acetylene gas at low pressure.
Method of Operation
- Generate acetylene gas using an acetylene generator.
- Supply the gas through hoses to the welding torch.
- Mix oxygen with acetylene in the torch.
- Ignite the mixture to produce the welding flame.
- Use the flame to melt and join metal pieces.
Types of Welding Joints
Welding joints are arrangements where two or more metal pieces are joined together by welding. According to BIS SP: 46-1988 specifications, several types of joints are commonly used in welding.
Butt Joint
A butt joint is formed when two metal plates are placed edge to edge in the same plane and welded together.
Uses
- Joining plates in pipelines
- Structural steel fabrication
- Pressure vessels
Fillet Joint
A fillet joint is used when two metal surfaces meet at an angle, usually at 90 degrees. The weld forms a triangular cross-section.
Uses
- Joining plates at right angles
- Fabrication of frames and structures
- Construction work
Gases Used in Welding
Different gases are used in gas welding to produce the welding flame.
Common Welding Gases
- Oxygen: Supports combustion and increases flame temperature.
- Acetylene: Fuel gas used to produce a high-temperature flame.
- Carbon Dioxide: Used as shielding gas in CO₂ welding.
- Argon: Used as shielding gas in TIG and MIG welding.
Gas Cylinders
Gas cylinders are strong containers used to store and transport welding gases under high pressure.
Description
Gas cylinders are made from high-strength steel and fitted with valves and regulators to control gas flow.
Kinds of Gas Cylinders
- Oxygen cylinders
- Acetylene cylinders
- Carbon dioxide cylinders
- Argon cylinders
Main Differences Between Oxygen and Acetylene Cylinders
| Oxygen Cylinder | Acetylene Cylinder |
|---|---|
| Contains compressed oxygen gas. | Contains dissolved acetylene gas. |
| Usually painted black or blue. | Usually painted maroon. |
| Supports combustion. | Acts as a fuel gas. |
| Used with fuel gases for welding. | Produces high temperature flame when mixed with oxygen. |
Uses of Welding Gases
- Producing welding flame in gas welding.
- Shielding the weld pool from air.
- Cutting and heating metal.
Conclusion
Welding operations require proper tools, equipment, and gases to achieve strong and reliable joints. Understanding welding hand tools, CO₂ welding, HP and LP gas welding equipment, types of joints as per BIS standards, and the characteristics of welding gases helps improve welding quality and safety in engineering workshops.