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Welding | Types of welded joints

Updated: Apr 20, 2021

What are different welding techniques?

Table of contents:

Earlier we had a look at what is welding and what are the elements involved in a welding operation.

Welding is a method of fabrication that joints material by means of elevated temperatures to melt the connecting parts and cooling them together causing fusion.

The general practice of welding involves two metals that are to be welded are brought closer. Electric current is passed through the metals and an electrode is introduced in the field to form an arc causing a rise in temperature.

We have looked at different welding practices. If not, please do check out our blog. In this article, we will take a look at what are the different types of joints in welding.

To begin with, we will first understand how the welded joints distinguished. Any specific type of joint is determined by the relative position between the two metals to be joined. What is relative position though?

The distance, angle and orientation of an object with respect to another object is the relative position.

Tee Joint

As the name indicates, the joint in the shape of a T is known as a tee joint. One piece of metal lays down flat, while another section is welded standing on its side or end upwards. It’s a simple-looking joint. Although this weld tends to be easier in most ways, it can prove challenging to execute, due to the weld pulling either direction from a lack of surface area holding between the two welds.

This welding method always has welds on both lengths of the upright plate and frequently has the ends welded, completing it with four sides fused to the base plate.

Butt Joint

Two plates, when butt up to each other are in general, aligned straight. This type of weld can have sections cut out of the corners of the plates in various shapes and sizes.

These are called weld preps and are added to provide more depth of weld to the joint. The joint can also have two square ends without any weld prep. Butt joints appear by means of butt welds. The adjoining of two plates by leveling their tops and bottom forms a butt joint.

The butt joint is the most challenging joint to achieve in reason with less visual control to place straight welds. To provide strong efficiency to the butt joint, butt welds are added with deep penetration.

Fillet Joint

The position of the fillet joint lies inside the corners of adjoining plates. The angle at which this joint is fitted lies within the angle range of 90 degrees up to the angle of 145 degrees. This concept of adjoining is quite easy to apprehend and remember from the word “fill it” any corner to fill the weld with. Fillet welded joints such as Tee, lap, and corner joints are the most common connection in welded fabrication.

Square Joint

The square joint represented by the symbol L is somewhat similar to the Tee joint. Consider two plates A and B held in an assembly in which plate A lays flat, while plate B stands on its tip flush with plate A’s end to get butt welded together.

A fillet weld is placed on the other side of the plate between the right angle. The dimensions of plates A and B, such as length, width, and thickness can be measured equal or different. A square joint can be made by welding either one end of plate A welded with plate B, subjected to the application of the project.

Lap Joint

A lap joint is the overlapping of one plate over another, parting two sections for fillet welds, one on the top and one underneath. In a Lap joint, we are able to achieve greater surface area between the two welds making it the most trustworthy welding connection. Two plates of varying thickness could be joined together by means of lap joint welding. Lap joints are also a kind of fillet weld, that can be made on both sides.

Edge Joint

When two plates are arranged in a face-to-face position somewhat similar to the lap joint with the alteration of joined edges, the edge joint comprises of one butt weld alongside three other welds that may be devoted by either fillets or butt welds.

One of the applications of edge welded joint is in attaching two metal plates with flanged edges. These joints are essential when the plates being joined have a thickness of less than 3-mm. To increase the strength of the joint, the filler metal is added to fuse the edge completely.

Corner Joint

When the corners of two plates coincide then the resulting joint is termed as “Corner joint”. The formation of the big V between the two corners depicts its weak assembly. The geometry followed between two corners is usually a 90-degree angle that can be varied.



  1. There are 7 types of welding methods to join two or more pieces of metal.

  2. A lap joint is commonly used with thinner material. A lap joint provides lateral strength to the assembly.

  3. The filler material used is the edge joint or lap joint has lower viscosity in higher temperatures to allow the joining material to slip into closed gaps.

  4. The thickness of the weld around the joint has to be uniform throughout. The strength of the assembled weld depends on the joint thickness.

  5. The levels of two plates when performing a butt-joint needs to be linear and at a 180-degree angle.


These are the possible ways we can do a welding operation. There are different parameters to consider while choosing the type of joint to be employed, though the load-bearing requirement and material properties are primary factors to keep in mind. To know more about the structural conditions and the factor while building a structure please stay tuned with us.

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