Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the U.S.) and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals, respectively. French engineers Edmond Fouche and Charles Picard became the first to develop an oxygen-acetylene welding machine in 1903.[1]
Oxy-fuel is one of the oldest welding processes, though in recent years it has become less popular in industrial applications. However, it is still widely used for welding pipes and tubes, as well as repair work. It is also frequently well-suited, and favored, for fabricating some types of metal-based artwork. Oxyfuel equipment is versatile, lending itself not only to some sorts of iron or steel welding but also to brazing, braze-welding, metal heating (for bending and forming), and also oxyfuel cutting.
In oxy-fuel welding, a welding torch is used to weld metals. Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten pool is generally supplied with additional metal called filler. Filler material depends upon the metals to be welded.
In oxy-fuel cutting, a cutting torch is used to heat metal to kindling temperature. A stream of oxygen then trained on the metal combines with the metal which then flows out of the cut (kerf) as an oxide slag [2].
Torches that do not mix fuel with oxygen (combining, instead, atmospheric air) are not considered oxy-fuel torches and can typically be identified by a single tank (Oxy-fuel welding/cutting generally requires two tanks, fuel and oxygen). Most metals cannot be melted with a single-tank torch. As such, single tank torches are typically used only for soldering and brazing, rather than welding.
Uses
Oxy-gas torches are used for or have been used for:
- Welding metal: see below.
- Cutting metal: see below.
- Also, oxy-hydrogen flames are used:
- In Stone Work for "flaming" where the stone is heated and a top layer crackles and breaks. A steel circular brush is attached to an angle grinder and used to remove the first layer leaving behind a bumpy surface similar to hammered bronze.
- In the glass industry for "fire polishing".
- In jewelry production for "water welding" using a "water torch". [1].
- Formerly, to heat lumps of quicklime to obtain a bright white light called limelight, in theatres or optical ("magic") lanterns.
- Formerly, in platinum works, as platinum is only fusible in the oxy-hydrogen flame and in an electric furnace.
[edit]Apparatus
The apparatus used in gas welding consists basically of an oxygen source and a fuel gas source (usually cylinders), two pressure regulatorsand two flexible hoses (one of each for each cylinder), and a torch. This sort of torch can also be used for soldering and brazing. The cylinders are often carried in a special wheeled trolley.
There have been examples of oxyhydrogen cutting sets with small (scuba-sized) gas cylinders worn on the user's back in a backpack harness, for rescue work and similar.
There are also examples of pressurized liquid fuel cutting torches, usually using gasoline. These are used for their increased portability.
