Oxy-fuel cutting is a powerful thermal cutting process used to cut ferrous metals. This highly popular metal-cutting method uses oxygen and fuel gases (such as propane, acetylene, propylene, MAPP, and natural gas) to cut through materials.
Also called ‘plasma cutting’, oxy fuelled cutting is one of the most widely used industrial thermal cutting processes. It can cut materials with thicknesses from 0.5 mm to 250 mm, and the cutting equipment is relatively low cost, available in both manual and mechanised form.
The cutting process is fairly simple. A mix of oxygen and the chosen fuel gas is used to preheat the metal to its ‘ignition temperature’ but well below its melting point. The ignition temperature can differ depending on the kind of metal; for example, steel is 700°C to 900°C.
Next, a jet of pure oxygen is applied into the preheated area, which sets off a strong exothermic chemical reaction between the oxygen and the metal, forming by-products consisting of iron oxide or slag. The cutting oxygen blows away the slag enabling the oxygen jet to penetrate through the material and continue to cut through it.
Electrically conductive ferrous metals are typically used in the oxy-fuel process. Some examples are:
• Low carbon steel
• Mild steel
• Medium carbon steel
• Hardened low carbon steel
When cutting steel, it’s important to note that only certain types of steel can be cut. For example, carbon steel or mild steel ranging from a low carbon content (less than 0.3% carbon) to a medium carbon content (0.3 to 0.6% carbon) work well with oxy-fuel cutting – but others do not.
Generally, non-ferrous metals and any corrosion-resistant metals are not suitable for oxy-fuel cutting. This is because of how the oxy-fuelled cutting process works; it oxidises the heated metal before blasting that oxidised metal away with pure oxygen, therefore making a cut as the gas flows through the material. As such, if the metal can’t oxidise (which means rusting), it cannot be cut using oxy-fuelled cutting.
Metals unsuited for oxy-fuelled cutting include:
We at KERF are industry experts in oxy-fuel, plasma cutting and waterjet cutting technology, processes and materials.
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