Welding joints types, symbols and pictures

Welding Joint Types

What is a Weld:

A weld is a permanent union between materials caused by the application of heat, pressure, or both and if made between two faces approximately parallel is known as a butt weld.

And a weld made between two faces that are approximately at right angles to each other is known as a fillet weld.

What is a weld Joint: A joint can simply be described as a configuration of members and can be described independently of how it is welded. A butt joint and a T joint are the most common type of weld joint.

Types of Welding joints

The main types of weld joints are:

  1. Butt Joint
  2. T Joint
  3. Corner Joint
  4. Edge or parallel Joint
  5. Lap Joint
  6. Cruciform Joint
  7. Flare Groove joint

What is a Butt Joint?

Butt Joint: In this type of joint, two metals are joined by simply placing their ends together and then performing the welding operation. These two objects are nearly parallel and do not overlap. This example shows a single V butt joint.

butt weld

Here various types of butt joints configurations are shown.

butt weld types
Figure 2. Types of butt joint configuration

What is T Joints or Fillet Joint?

 2. T joint or fillet joint is a Connection between the end or edge of one part and the face of the other part. As the name suggest, two plates or pipe are 90 degree to each other forming the letter T shape. Take your time to get familiar with different types of T joint weld configurations.

T joint
Figure 3. T Joint or Fillet Joint

Here various types of T Joint configurations are shown.

T joint types

What is a Corner Joint?

3. Corner Joint: A corner joint is a Connection between the ends or edges of two parts making an angle to one another of more than 30 but less than 135 degree in the region of the joint. They are having two types mainly:

  1. Closed corner joint
  2. Open corner joint

What is a Edge Joint?

4. Edge Joint: An edge joint or simply called parallel joint is a connection between the edges of two parts making an angle to one another of 0-30 degree inclusive in the region of the joint. 

edge joint

Take your time to get familiar with different types of edge joint weld configurations. shown below:

edge joint types
Figure: Types of corner joints

What is Lap joint?

5. Lap Joint: A lap joint is a Connection between two overlapping parts making an angle to one another of 0 to 5 degree inclusive in the region of the weld or welds. When designing a lap joint the overlap between the two plates needs to be at least four times the plate thickness, but not less than 25mm.

lap joint
Figure: Lap joint configuration

What is Cruciform Joint?

6. Cruciform joint:  is a specific joint in which four spaces are created by the welding of three plates of metal at right angles as shown here. In the American Bureau of Shipping Rules for Steel Vessels, cruciform joints may be considered a double barrier if the two substances requiring a double barrier are in opposite corners diagonally. Double barriers are often required to separate oil and seawater, chemicals and potable water, etc.

cruciform joint

What is a Flare Bevel Joint?

7. Flare Bevel Joint:   Flare bevel joints are formed between round member or atleast one plate member. A simple flare groove joints are shown in below figure.

flare joint
Flare Bevel Joint

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