Electric welding is a process of joining two metal pieces using heat generated from an electric arc. The arc melts the base metal and filler material (electrode), which fuses together to form a strong joint upon cooling.
Parts of Electric Welding
Figure 1.
The main components of an electric welding setup include:
- Power Source (G) – Provides the necessary electric current for welding.
- Electrode Holder – Holds and feeds the welding rod to the workpiece.
- Welding Rod (Electrode) – Acts as a filler material that melts and deposits onto the base metal.
- Base Metal – The workpiece that needs to be joined.
- Deposited Metal – The material that forms the weld after cooling.
Working of Electric Welding
When the welding rod (electrode) touches the base metal and is then slightly withdrawn, an electric arc is generated. The high temperature of the arc melts both the base metal and the welding rod. The molten metal solidifies to form a strong bond between the two workpieces. A shielding gas or flux may be used to prevent oxidation during the welding process.
Electric Welding Equipment
| Equipment | Description |
|---|---|
| Welding Machine | The power source for electric welding, provides the necessary current to create the welding arc. |
| Electrode Holder | Holds the welding electrode, allowing the welder to manipulate it during the process. |
| Welding Rod | A consumable electrode used to provide filler material to the weld joint. |
| Ground Clamp | Used to complete the electrical circuit by attaching to the workpiece. |
| Protective Gear | Includes gloves, helmet, and clothing to protect from sparks, heat, and UV radiation. |
| Welding Helmet | Protects the welder’s face and eyes from harmful UV radiation and flying debris. |
| Chipping Hammer | Used to remove slag from the welded joint after welding. |
| Wire Brush | Used to clean the weld area and remove any remaining slag or debris. |
Types of Electric Welding
Figure 2: Classification of electric welding.
Electric welding is classified into two major types: Resistance welding and Arc welding. Here’s a breakdown of the classification:
- Resistance Welding:
- Spot welding: A process in which heat and pressure are applied to the contact points between two pieces of metal to create a weld at those points.
- Seam welding: Similar to spot welding, but it involves continuously joining metal sheets or plates, typically using rotating electrodes.
- Projection welding: This method uses projections or raised areas on the workpieces to localize the heat, creating a stronger weld at specific points.
- Butt welding: The edges of two pieces are brought together, and heat is applied to join them.
- Upset butt welding: A variation of butt welding where the parts are forced together under pressure during welding.
- Flash butt welding: Involves generating heat at the butt of the materials by a controlled electric arc, which then melts and joins the materials.
- Arc Welding:
- Metal arc welding: A welding process that uses an electric arc to melt the metal at the joint.
- Carbon arc welding: Uses a carbon electrode to generate the arc, typically used for welding non-ferrous metals.
- Helium (or argon) welding: Uses an inert gas like helium or argon to shield the weld from contamination, making it suitable for welding highly reactive materials.
- Atomic hydrogen arc welding: Uses hydrogen as the arc-forming gas to produce a high temperature, suitable for welding metals like aluminum and magnesium.
This classification outlines the various methods used in electric welding, each serving different applications based on materials, welding conditions, and desired outcomes.
Advantages of Electric Welding
- Strong and Durable Joints – Produces high-strength welds.
- Cost-Effective – Requires less manual effort compared to traditional methods.
- Fast Process – Welding speed is higher than other joining techniques.
- Wide Material Compatibility – Can be used for different metals and alloys.
- Automation Possible – Suitable for robotic and automated welding processes.
Disadvantages of Electric Welding
- High Energy Consumption – Requires a significant amount of electricity.
- Requires Skilled Labor – Operators need training to achieve good quality welds.
- Health Hazards – Fumes, radiation, and high heat can be dangerous without proper precautions.
- Risk of Defects – Poor control of heat can lead to weak joints, cracks, or porosity in the weld.
Applications of Electric Welding
- Automobile Industry – Used in manufacturing and repairing vehicle frames and components.
- Construction – For joining steel structures, pipelines, and bridges.
- Shipbuilding – Essential for fabricating large metal structures in ships.
- Aerospace Industry – Used for high-strength and lightweight structures.
- Manufacturing & Fabrication – Commonly used in machine and equipment assembly.