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Back Mechanical Mechanical Engineering Dictionary Machine Design Welding - Definition, Types and Advantages of Welding | Disadvantages

Welding - Definition, Types and Advantages of Welding | Disadvantages


A welded joint is a permanent joint used extensively in fabrication process. An electronic process for fusion welding arc or gas welding is used for fusion of the material. It is also used for repair work build up a small part that has broken off e.g. to repair a worn surface.


Welding processes are mainly classified as:

  1. Fusion welding
  2. Forge welding

1. Fusion welding

In this process the part to be joined are held in proper position while the molten metal is supplied to the joint. By heating the joint surface become plastic or molten. When the molten metal fuses the joint is formed.

2. Forge welding

In this type of welding the parts are first heated to a proper temperature in a furnace or forge and then hammered


The following are the advantages of welding

  1. Welded joints are greater in strength
  2. The process are noiseless
  3. Welded joint can easily be repaired
  4. Welded joints have low initial cost
  5. Less matching is required after welding


The following are the disadvantages of welding

  • Welded joints can not be used for collision and vibration.
  • Welded joints can not be assembled and reassembled.

Welded joints

Welded joint as is clear from its name is obtained by the fusion edges of the parts to be joint together, with or without the application of pressure and filler material. An electric arc or gas is used for fusion of the material.

Types of welded joints

There are commonly two types of welded joints

A: Fillet joint or lap joint
B: Butt joint

Fillet joint or lap joint

In this type of the plates are over lap and then welding the edges the plates. The lap joint may be classified as
1. Single transverse fillet joint
2. Double transverse fillet joint
3. Parallel fillet joint

A single transverse lap joint has the disadvantage that the edge of the plat which is not welded can rap out of shape.

Butt joint

In this type of joint is obtained by placing the plates edge to edge and then welded.
The butt joint may be classified as

  1. Square joint
  2. Single v joint
  3. Double v joint
  4. Single u joint
  5. Double u joint

The other types of welding joint are Corner joint, T joint, Edge joint.

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