When using flame cutting, one of the gases is indispensable, which is oxygen. It is required both when combustible gases are burned and when the steel is burned after reaching the ignition point. Therefore, it is required that the oxygen to be used has a high purity, which is generally more than 99.5%.
Some industrial standards in advanced countries require that the purity of oxygen be 99.7% or more. Each 0.5% reduction in oxygen purity reduces the cutting speed of the steel plate by about 10%.
If the oxygen purity is reduced by 0.8%-1%, not only the cutting speed will be reduced by 15%-20%, but also the kerf will be widened, the slag at the lower end of the incision will be more difficult to clean, and the quality of the cut section will also be significantly deteriorated.
Gas consumption also increases. Obviously, this reduces production efficiency and cutting quality, and also significantly increases production costs.
In fact, in addition to oxygen, we can also use liquid oxygen, although its one-time investment is relatively large, but from an economic point of view, it is much better.
The stability of the gas pressure is also crucial for the quality of the workpiece as it affects the quality of the workpiece. If the oxygen pressure fluctuates, it will seriously affect the cutting section. The pressure, in turn, is related to the type of nozzle used, the thickness of the steel plate being cut, and other factors.
In steel flame cutting, acetylene, gas, natural gas, and propane are commonly used as flammable gases. Some foreign manufacturers also use MAPP, namely: methane + ethane + propane. The gas with high combustion rate and high combustion value is more suitable for thin plate cutting, and vice versa for thick plate cutting, especially for steel plates with a thickness of 200 mm or more.