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
f) Helmet
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