Oxygen fueled cutting for mild steel
In oxy-fuel cutting, oxygen is used as the cutting gas. The cutting is started by heating the edge of the steel to the ignition temperature, and then the cutting torch blows excess oxygen into the workpiece at a higher pressure. The chemical reaction releases a lot of energy, causing the metal to burn and blowing the resulting molten oxide to the other side. Oxygen chemically combines with the iron in the iron-containing material to immediately oxidize the iron into molten iron oxide, producing chips. Starting a cut in the middle of the workpiece is called piercing.
Cutting vs. welding
The cutting and welding of oxyfuel are related technologies, and the main difference lies in the temperature reached. The purpose of welding is to slightly melt the welded parts so that they can be joined together to form a whole after cooling; during the cutting process, the material is heated to ignition temperature. The ferrous metal is burned into iron oxide, which is blown out from the incision in the form of molten slag.
How does it work?
In both processes, a combination of pure oxygen and combustible gas (such as acetylene, propane or less common natural gas) is used. Compared with ordinary air, oxygen can make the flame reach higher temperature. When the propane flame burns at a temperature of about 2000°C, it can combine with oxygen up to 2500°C, and the oxyacetylene flame can even reach 3500°C. Chemically, it is the exothermic oxidizing gas of the fuel. In short, the energy of molecules produced by the combination of oxygen and fuel particles is lower than the energy of individual oxygen and fuel molecules. The excess energy will be released in the form of heat, which will burn the cut metal. This combustion is also exothermic oxidation-the combination of oxygen and iron molecules forms iron oxide while releasing heat, which makes the material cut much faster than when it is melted.
