The typical types of welding joints are:
- Butt joint
- Corner joint
- Edge joint
- Lap joint
- Tee joint
A butt weld is a weld that joins two pieces of metal together face to face with the edges in line or nearly in line. It is the simplest form of welding and so-called because it resembles the butts one sees at either end of planks at a joint.
A corner weld is similar to a butt weld except that two pieces meet at an angle instead of directly against each other. Common forms include square corners, fillets, and T-joints.
An edge joint is where two surfaces are touching. You might want to use an edge joint if the two surfaces are not touching for a long time.
A lap joint is a type of welded joint in which a portion of one member laps over onto another, usually to join the member end to end. A common form is the lap joint where the members have their edges butted together and this forms a simple cover for an object such as a pipe or tube. In thicker materials, it may be necessary to provide additional support by adding verticals called ‘piping’ at intervals along the length.
A tee joint is similar to a corner weld except that there are generally three pieces being joined together rather than just two. The pieces are placed next to each other with their ends flush and then welded together along their entire lengths. This can also be done by welding a short piece perpendicularly across the ends of two pieces and then welding these together.