Butt welding

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For butt welding plastic, see Butt heat fusion. For the general welding geometry, see Butt joint (welding).
Video: Automatic butt-welding machine

Butt welding is a welding technique used to connect parts which are nearly parallel and don't overlap. It can be used to run a processing machine continuously, as opposed to having to restart such machine with a new supply of metals. Butt-welding is an economical and reliable way of joining without using additional components.

Usually, a butt-welding joint is made by gradually heating up the two weld ends with a weld plate and then joining them under a specific pressure. This process is very suitable for prefabrication and producing special fittings. Afterward, the material is usually ground down to a smooth finish and either sent on its way to the processing machine, or sold as a completed product.

This type of weld is usually accomplished with an arc or MIG welder. It can also be accomplished by brazing. With arc welding, after the butt weld is complete, the weld itself needs to be struck with a hammer forge to remove slag (a type of waste material) before any subsequent welds can be applied. This is not necessary for MIG welds however, as a protective gas removes any need for slag to appear. Another with a MIG welder is that a continuous copper coated wire is fed onto the stock, making the weld virtually inexhaustible.[1]

Hand welding[edit]

A joint between two members aligned approximately in the same plane. Butt welding can also be achieved through traditional blow torches in the most common form of butt joints, a process that uses some variety of flux, usually a tin-based solder and precise hand-eye coordination that is common for hand-made boxes of copper, brass, and silver. There are two types of butt welding; one is carried out by smiting and another is carried out by welding two work pieces by non-overlapping.

The process consists of two desired strips of metal that are lined with flux that is lightly dried with a blowtorch until it is a sticky consistency, followed by cutting a strip of solder that is generally 20% of the full joint's size. Applying heat gently makes the gel-like flux now appear white and powdery which now is primed to be welded in which the blow torch is arched so that the "heat cone", the bluest and hottest part of the flame, is now directly upon the solder melting the joints together evenly.

The joint is then cooled and cleaned in a solution of sulfuric acid diluted in 20 parts water – commonly known as "pickle" – to remove imperfections. Sanding and polishing then achieves the desired finishing.

Upset Weld[edit]

The parts to be welded are clamped edge to edge in copper jaws of the welding machine and brought together in a solid contact so that their point of contact forms a locality of high electric resistance, while current flows to heat the joint . At this point the pressure applied upsets or forges the parts together . Upset buttwelding is used principally on non ferrous materials for welding bars, rods, wire, tubing, formed parts, etc.


EN 1993-1-8, which covers the design of joints in the design of steel structures, defines a set of provisions for welding structural steel.

See also[edit]

�with or without the application of pressure, or by pressure alone, and

�with or without the use of filler metals


  1. ^ Britannica Concise Encyclopedia (2003) p. 1997

Further reading[edit]