Glossary - B
Backfire occurs when the flame burns back into the torch. It is characterised by a loud bang and is often a sign that there is a fault in the equipment or gas supply e.g. incorrect pressure settings; gas cylinder running low; large pressure drops in the hoses; dirt or carbon blocking the nozzle and restricting the gas flow or the equipment becoming overheated. The removal of weld metal and base metal from the other side of a partially welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side. A material or device placed against the back side of the joint, or at both sides of a weld in electroslag and electrogas welding, to support and retain molten metal. The material may be partially fused or remain unfused during welding and may be metal or non-metal. An SI unit of pressure widely used in the gas industry to describe the filling pressure of cylinders and the rating of gas equipment such as regulators. A bar is defined as #100,000 Newtons / m{2} and 1.01325 bar equals one atmosphere. Usually applied to steel MIG wire which does not have a copper-coating. The wire does have rust-inhibiting treatments applied to the wire surface. An alternative description for Non-coppered MIG wire. The metal to be welded, brazed, soldered, or cut. The angle formed between the prepared edge of a member and a plane perpendicular to the surface of the member A term sometimes used to describe a tangle of wire in the wire feed unit of a MIG welding machine. The process whereby a liquid becomes a gas as the result of the input of heat. The temperature at which a liquid starts to boil to form a vapour. This temperature is dependent on the pressure the liquid is under. A non-fusion joining process which uses capillary action to draw a filler material into the joint to form a bond. The properties of the joint are not the same as the parent metal. Brazing uses a filler material which melts at above 450 degrees Celsius. The British Standards Institute. Standards published by this organisation are denoted BS and are generally followed by a number and date e.g. @BS341. Part 1 1991 - Valve fitting for compressed cylinders. Over a hundred standards are relevant to cutting and welding and relate to design, inspection, testing and maintenance of cylinders and equipment ; safety clothing; consumables and welding practice. British Standards are increasingly being replaced by European standards in which BSI inputs the UK view. These standards are denoted BS EN. A packaging method whereby large quantities of continuous MIG wire can be supplied to enable robots or automatic welding machines to continue welding for long periods without interruption. The packs may contain, typically, 200, 250 or 350 kg of wire, compared with the 15kg or so on a reel. The type of joint formed when two plates are joined edge to edge in the same plane. A Butt joint can only be made effectively by welding. The type of joint formed when two plates are joined edge to edge in the same plane. A Butt joint can only be made effectively by welding.
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