Definition - What does Butt Weld mean?
A butt weld is a type of circumferential joint where molten metal is applied around the joint to attach pipes to each other. The butt weld is one of the processes used in electrical resistance welding (ERW.)
ERW is a form of pressure welding that utilizes heat generated by the electrical resistance of the material along with applied force to hold the pieces together during the welding process.
Some of the steel pipes used for trenchless construction and rehabilitation processes are made by ERW in which metal is rolled and welded longitudinally. These pipes are used for low pressure or medium pressure applications such as transporting oil and water.
Trenchlesspedia explains Butt Weld
The butt welding process is one of the earliest forms of resistance welding. In this process, the two metal pipes to be welded are first brought together under pressure. A current is then applied, which heats the contact area sufficient enough to allow the applied pressure to forge the parts together.
The current and pressure are applied constantly throughout the butt welding cycle until the joint becomes plastic. The pressure that is still in action overcomes the softened area and produces the forging effect and the subsequent welded joint.
Butt welding is preferred for joining metal pipes as it is economical and provides a strong fusion of the metal surfaces.