The art of welding is creative that needs patience and keen observation. Welders must have information about welding and types of welding joint designs since the uses of welding do not have any limits. However, little knowledge about welding will not help you in any way. Instead, it will lead to structural failures.
In this guide, you will be given information about the welding joint types. The aim is to help you understand basic knowledge related to welding. There are five major welding joints as Butt joint, Lap joint, Corner joint, Edge joint, and Tee joint. Each requires different welding processes and provides weight, durability, strength, and rigidity.
Understanding 5 Basic Weld Joint Types
Welding joints are mainly classified into the following:
1: Butt Joint
The butt joint is the cost-friendly and universally used type where two metal pieces are put together in the same plane side by side and are welded in a parallel position. Most commonly used for attachment of pipe, fittings, flanges, valves, etc., you can create different welding styles with a butt joint, each of which has a different function.
For instance, Square, Single bevel, Double bevel, Single J, Double J, Single V, Double V, Single U, and Double U welds are some common examples of butt joints.
During the welding process, the surface area of metal is melted down, known as the faying surface. In addition, it is shaped beforehand to add more toughness to the weld’s strength for deeper weld penetration smooth appearance, and this procedure is known to be edge preparation.
When welding thicker metals or pipes, alter the joint design to get sound weld penetration because until and unless you employ some grove, you cannot achieve 100% welding penetration. You can achieve full welding penetration by using thinker metal pieces to make a square butt joint. In addition, you can avoid occurring defects such as cracking, incomplete or poor penetration, and porosity by improving welding butt joints variables.
2: Lap Joint
Usually, when two pieces of metal of different thicknesses are welded together in an overlapping position, it is a lap welding joint. You can weld the two pieces on either one or both sides. When they are welded on both sides, it provides extra strength. Lap joints fall under the category of butt joints as lap joints are an improved form of Butt joints.
Mainly lap joints are not used for welding thicker material together but are more compatible with sheet metal. However, the major disadvantage of a lap welding joint is corrosion or rust when metals are in an overlapping position. Such defects can be fixed by employing the correct method and techniques.
3: Tee Joint
As the name suggests, when two pieces are put together in a “T” shape, an edge lies at the center of the other and intersects at a 90-degree angle. You can also use a pipe or tube onto a base metal to form tee joints. To create tee joints, there are multiple welding styles, such as , Flare-bevel-groove weld, Slot weld, Fillet weld, Plug weld, J-groove weld, and Melt-through weld.
If you are using a thicker metal base, then in such a case, you need to use grooves so that the welding can withstand the load on both sides. However, tee joints rarely use grooves. Lamellar tearing is a common drawback of tee joints, which takes place because of limitations faced by the joints. To avoid lamellar tearing and other joint deformities, it is suggested to set a stopper.
4: Edge Joint
When two or more metal pieces are welded together in an adjacent and parallel position, the metal sheets can be placed parallel or flanging edges in the edge joint. The edge welding joint aims to distribute stress equally when the metal sheets are joined together. The type of stress caused in welding joints can be compression, torsion, tensile, bending, and sheer.
Nonetheless, we take the help of filler metal for heavier applications. The purpose of adding Filler metal is to strengthen the plate and secondly to melt or fuse the edge entirely. Two things, such as joint design and weld integrity, make the edge welding joint withstand stress forces. At the same time, few joints can bear specific stress forces well compared to others.
Whatever welding process you choose automatically has an impact on the selection of joint design as well. Every welding mechanism features specific characteristics that affect the performance, like heat input, rate of travel, deposition rate, and penetration.
Welding styles use edge joints to create J-groove weld, U-groove weld, Edge-flange weld, or butt V-groove weld, Bevel-groove weld, Square-groove weld, and U-groove weld. Some defects in edge welding joints, such as corrosion, lack of fusion, slag inclusion, and porosity, may occur because of overlapping positions.
5: Corner Joint
A corner joint is formed when you combine one corner of the metal with another corner to obtain an ‘L’ shape. This type of welding joint is quite popular in the sheet metal industry and is used for applications such as frames, boxes, and the construction of other similar fabrications. The corner joint is pretty much similar to tee joint welding.
The only difference they have is in the location of metal is being placed. The tee joint meets the metal piece at the center of the other metal piece while the corner joint intersects at a right angle between two metal pieces to form an L shape. Corner-flange weld, Fillet weld, V-groove weld, Square-groove weld, butt weld, Bevel-groove weld, Flare-V-groove weld, and J-groove weld are some of the welding styles used to create corner joints.
The flaws corner joint has of lamellar tearing that welders can overcome by changing the joint design, using a buttering layer on the joint sides, reducing restraints, and employing a material tested by STRA, which is an abbreviation of a short transverse reduction in area.
This was a detailed review of types of welding joints to provide you with the knowledge that is important for welders. Such information can help in anticipating and recognizing different forces used in the field of weldment. It is essential to understand these forces that enable you to determine the best joint design and prevent structural failure caused by these forces. You can also have a look at our article that how you can join metal without welding.