What is Arc Welding Process?
- The electric arc welding process is a fusion welding process in which welding heat is obtained from an electric arc between an electrode and the workpiece.
- The electrode is first allowed to touch the work piece to form an electric circuit and then separated continuously to flow through the gaseous medium.
- The temperature produced at the centre of the arc is 6000 °C to 7000 °C.
- In this, the base metal is melted by the temperature of the arc, forming a molten metal which is forced out of the pool by blast from the arc.
- Electrode metal also gets melted and deposited at the weld.
- Either A. C. or D. C. supply is used for arc welding process.
- The electrodes used in the process are of two types that is bare electrodes and coated electrodes.
- Bare electrodes are cheaper but welds produced through these are of poor quality whereas, coated electrodes are used in modern welding machines as they carry a core of bare metallic wire produced with coating on the outer surface.
- The length of electrodes varies from 250 mm to 450 mm whereas, diameter from 1.6 mm to 9 mm.
Arc Welding Equipment’s
The most commonly used equipment’s for arc welding are as follows:
a) A.C or D.C. machine
b) Wire brush
c) Cables and connectors
d) Earthing clamps
e) Chipping hammer
g) Safety goggles
h) Cable plug
i) Hand gloves, apron, etc.
Advantages of Arc Welding Process
- It is the most versatile process which can be applied for thin and thick sections.
- Welding of complicated shapes can also be done.
- Welding can be done in any position with high weld quality.
- Very neat appearance and smooth weld shapes can be obtained.
- Generally, edge preparation is not required.
- The equipment’s are portable and less expensive.
Disadvantages of Arc Welding Process
- As the electrodes are coated, the chances of slag entrapment and their related defects are more.
- Welding control is difficult.
- The process needed filler material.
- It is a slow process.
Applications of Arc Welding Process
Arc welding is commonly used in the manufacturing of following parts:
- Air receiver, boilers, pressure vessels fabrication.
- Automobile, chemical and aircraft industry.
- Ship building and bridge construction.
Types of Arc Welding Process
The main types of arc welding process are as follows:
1. Shielded metal arc welding
2. Gas tungsten arc welding (TIG)
3. Gas metal arc welding (MIG)
4. Electroslag welding
5. Plasma arc welding
6. Stud arc welding