What are the different types of welding joints?

The applications of welding are quite limitless. From high-level industrial processes to residential construction and small-scale projects, welding is applicable in joining important materials. Over the years, there has been steady progress in welding technology and there are currently different processes that can be used to join workpieces – metals and plastics, mostly – to obtain the perfect construction.  While the welding process used has a significant impact on the strength and integrity of any construction, the welding joint determines the usefulness of the construction.

types of welding joints

Types of welding joints

There are different types of welding joints. These joints are made to stand up to the needs and forces of each application. If you are new to welding, there is a need to understand these different types of welding joints and their major applications. There are basically five types of welding joints including butt joint, corner joint, lap joint, tee joint, and edge joint. We will describe these different joints as briefly as possible:

1. Butt Joint

butt joint welding

Butt welding joints are formed by placing the ends of two parts together side by side or in the same plane. It is the commonest type of joint in automated welding and is one of the easiest to construct too. It is also regarded as the universally accepted method of attaching a pipe to itself, fittings, flanges, valves, and other equipment. It includes different types of welding including Square butt, Bevel groove, V-groove weld, J-groove, U-groove, Flare-V-groove, and Flare-bevel-groove butt welding. It is commonly applied in instances where quality weld is desired and it will be hard not to find something that uses it.

Butt joint is normally used for materials up to 3/16 inches thick. If the material to be welded with this type of joint exceeds the maximum 3/16 inches in thickness, the ends of the pipes, fittings, and flanges should be chamfered at approximately 37.5-degrees, flared on a small upright side. When the plates are beveled, the butt welds will be correctly called groove welds. There will be need for more filler metal in this type of joint to improve the strength of the joint.

2. Corner Joint

corner-joint-welding

Corner joint is formed by joining two pieces of metal at a right angle to each other. This type of wield is commonly used in the sheet metal industry to attach pieces during the construction of boxes, frames and other such fabrications. When two metals are joined in a right angle for the corner welding joint, they form the L-shape. This shape is widely used for the creation of different shapes you will find in the construction industry.

Corner joint includes different types of welding such as Fillet, Spot, Square-groove or butt weld, V-groove, Corner-flange weld, Bevel-groove, U-groove, J-groove, Flare-V-groove, and Edge weld. Another important thing to note about this weld is that it is normally done on the outside of the corner. It is also the type of joint that gets replaced fairly often due to the pressure that most corners of structures bear.

3. Lap Joint

lap-joint-welding

Lap welding joints are formed when two pieces of materials are placed one on top of the other and joined through the welding process. They are usually used when welding pieces that have different thickness and can be done on one or both sides of a sheet of metal or other materials, depending on how strong it needs to be and the intending use. Lap welding joints are mostly used in electron beam, gas tungsten arc weld, gas metal arc welding, laser beam, and resistance spot welding. The joint can be found in a variety of weight & exercise machines, as well as industrial equipment.

While lap joint is not the commonest type of welding joint, it is applicable in such welding styles as Spot weld, Slot weld, plug weld, Bevel-groove weld, Fillet weld, Flare-bevel-groove weld, and J-groove weld.

4. Tee Joint

tee-joint-welding

Tee joint is formed when two parts of metal or other material are intersected at a 90-degree angle with one edge lying at the center of the other. When the materials are welded together in this unique position, they form the letter ‘T’, which is where the name comes from. The edge of one of the workpiece is placed on top of the one beneath and the weld takes place at that intersection. It normally requires the use of the fillet weld, which will be applied on both sides of the metal. Extra care is necessary to ensure effective penetration into the roof of the weld.

Tee joint is one of the commonest welding joints. It constitutes an essential part of the construction of many structures. It is majorly applicable when a metal part is connected to some type of base. It is also widely applicable when a pipe is welded onto a base of metal, attaching tin plates, as well as in many structural and machine applications. Several welding styles can be used to create a Tee joint including Fillet weld, Slot weld, Plug weld, Bevel-groove weld, Flare-bevel-groove weld, J-groove weld, and Melt-through weld.

5. Edge Joint

Edge joint is the type of joint that results from joining the edges of two parts of materials. It is mostly applicable to sheet metal parts where the edges of two sheets are expected to be adjacent and in approximately parallel planes. It is also used for sheet metals that have flanging edges. In this type of joint, the edges are simply placed side by side and welded. Normally, the weld does not penetrate completely the thickness of the joint. This is the major reason it is not used in stress and pressure applications. For heavier applications, filler metal will be added to melt or fuse the edge completely and reinforce the plate.

Different welding styles are used to create edge joints including Square-groove or butt weld, Bevel-groove, V-groove, J-groove, U-groove, Edge-flange, and Corner-flange weld. Edge joint is the type of welding joint that gets replaced often since it tends to get brittle over time.

Conclusion

Understanding the different types of welding joints is important for anyone interested in any form of construction that involves welding. The different types of joints are applicable in different types of tasks and it is important that the right joints are used in the right parts of a structure. Understanding the welding styles applicable in the different joints is also important to make sure that the quality of welding is top-notch to keep structures strong and intact over time.

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