Types of welding joints

In the fusion ( arc and gas) welding, five fundamental joints that are commonly used for most welds consist of: Lap join, butt join, corner joint, T-joint, and the last is Edge joint

Lap joint:

The lap joint is covered by over lapping the 2 plates and welding the edges of the plates. Its purpose is to combine the plates with 3mm thick or less. The lap joint may be single transverse, double transverse and parallel lap

Welding Styles Used To Create Butt Joints:

  • Slot weld
  • Plug weld
  • Bevel-groove weld
  • Spot weld
  • Flare-bevel-groove weld
  • J-groove weld

Butt joint:

​A butt weld, or a square-groove, is the most common and easiest to use. Consisting of two flat pieces that are parallel to one another, it also is an economical option. It is the universally used method of joining a pipe to itself, as well as flanges, valves, fittings, or other equipment. However, it is limited by any thickness exceeding 3/16”.

Welding Styles Used To Create Butt Joints:

  • Slot weld
  • Plug weld
  • Bevel-groove weld
  • Spot weld
  • Flare-bevel-groove weld
  • J-groove weld

T- joint

Tee joints are used to weld twoplates or sections whose surfaces are locatedapproximately 90° to each other at the joint.The included angle of bevel in the preparation of teejoints is approximately half that required for butt joints.

Welding Styles Used To Create T-Joints

  • Plug weld
  • Fillet weld
  • Bevel-groove weld
  • Slot weld
  • Flare-bevel-groove weld
  • J-groove weld
  • Melt-through weld

Corner joint

​A corner weld is a type of joint that is between two metal parts and is located at right angles to one another in the form of a L. As the name indicates, it is used to connect two pieces together, forming a corner. This weld is most often used in the sheet metal industry and is performed on the outside edge of the piece.

Welding Styles Used To Create Corner Joints:

  • Spot weld
  • Fillet weld
  • V-groove weld
  • Square-groove weld or butt weld
  • U-groove weld
  • Bevel-groove weld
  • Flare-V-groove weld
  • J-groove weld
  • Corner-flange weld.
  • Edge weld

Edge joint

Edge welding Joints are often applied to sheet metal parts that have flanging edges or are placed at a location where a weld must be made to attach to adjacent pieces.  Being a groove type weld, Edge Joints, the pieces are set side by side and welded on the same edge.  For heavier applications filler metal is added to melt or fuse the edge completely and to reinforce the plate.

Welding Styles Used To Create Edge Joints:

  • Bevel-groove weld
  • Square-groove weld or butt weld
  • J-groove weld
  • V-groove weld
  • Edge-flange weld
  • U-groove weld
  • Corner-flange weld