1.
Introduction to Arc Welding
Arc welding is a process of joining metals by
using an electric arc. The arc produces very high
heat, which melts the metals and joins them
together.
2. History of Arc Welding
Arc welding was first developed in the late
1800s. Over the years, it has become one of
the most common welding methods in
industries.
3. Basic Principle
When electricity flows through the
electrode and touches the work piece,
an electric arc is created. The heat of
the arc (about 3,000–20,000°C) melts
the metal edges and creates a strong
joint.
4. Main Components
• Power Source – Provides electric current (AC or DC).
• Electrode – Can be consumable (melts and becomes part of the weld) or non-consumable.
• Workpiece – The metal parts to be joined.
• Cables & Holder – Carry current to the electrode.
5. Types of Arc Welding
• SMAW (Stick welding) – Simple and widely used.
• MIG Welding (GMAW) – Uses a wire electrode and shielding gas.
• TIG Welding (GTAW) – Uses a tungsten electrode for clean, precise welds.
• FCAW – Similar to MIG but uses flux in the wire.
6. Welding Process Steps
1. Clean and prepare the metal.
2. Place electrode close to the workpiece.
3. Strike the arc.
4. Melt and move along the joint.
5. Let it cool and solidify.
7. Advantages
• Strong and durable welds.
• Low cost compared to other methods.
• Works on thick and heavy metals.
• Portable equipment.
8. Disadvantages
• Needs skilled operators.
• Produces fumes and UV radiation.
• Not good for very thin metals.
• Can cause defects if not done properly.
9. Safety Precautions
• Always wear helmet, gloves,
and protective clothing.
• Work in a well-ventilated area.
• Keep fire extinguisher nearby.
• Avoid looking at the arc
without protection.
10. Applications
• Building and construction
(bridges, structures).
• Vehicle manufacturing and
repair.
• Shipbuilding and pipelines.
• Heavy machinery and tools.
THANK YOU
K.Anjula Dilshan
