Following are the types of welded joints
- Butt joint
- Lap joint
- Corner joint
- Flange joint
Butt joint is a joint in which the corners or the edges of two metal parts are joined. The process is done by keeping the metal parts on a same plane. The edges of metal parts of thickness upto 5 mm may be kept open square. If the thickness of the metal parts exceeds 5 mm, edges of the parts need to be prepared in proper shape before welding.
It is a joint in which the metal plates are placed overlapping before welding. The edge of one part is welded with the surface of the other plate. There are two types of lap joint namely (i) Single lap joint and (ii) double lap joint.
This joint is made by keeping the metal plates at perpendicular (90°) to each other. Sheets with thickners over 3 mm only are welded by this type.
Two metal sheets kept at 90° to each other are welded by this joint. This method is adopted when making boxes and tanks. Corner joints are adopted for thin and thick sheets.
The plates of the joint may be kept parallel or at 90° to each other. The edges of the plates are bent to form the shape of a flange.