Oxy-fuel cutting is a processes that use fuel gases (Acetylene) and oxygen to cut metals.
A mixture of oxygen and the fuel gas is used to preheat the metal to its ignition temperature.
Cutting process is made using a cutting torch with orifices placed around a central jet (that carry only oxygen). Preheat flames of oxygen and acetylene are used on the outer jets. To change the direction of cutting without changing the position of the nozzle or the angle which the torch makes with the direction of the cut is possible because of using of several preheating flames.
This heats the metal up to melting point and then directs a stream of oxygen onto the spot, thus causing the metal to burn and melt along the required line.
Oxy-acetylene torches can easily cut through ferrous materials in excess of 200 mm (8 inches). Oxygen lances are used in scrapping operations and cut sections thicker than 200 mm (8 inches). Cut-off grinders are useless for these kinds of application.
IMPORTANT:
- Safety first. ONLY a professional can use such machines.
- The oxygen flowrate is critical. too little will make a slow ragged cut, while too much will waste oxygen and produce a wide concave cut.
- The oxidation of iron by this method is highly exothermic. Once it has started, steel can be cut at a surprising rate, far faster than if it were merely melted through.
- Since the melted metal flows out of the workpiece, there must be room on the opposite side of the workpiece for the spray to exit.