In the field of modern metal processing, plasma cutting machines are widely used in various metal sheet cutting operations due to their advantages such as fast cutting speed, high precision, and easy operation. However, to fully utilize the efficiency and quality of plasma cutting, it is crucial to choose the appropriate cutting gas. The gas not only affects the cutting quality but also relates to the service life and operating costs of the equipment. Therefore, understanding the characteristics and applicable ranges of different gases is the key to proper use of plasma cutting machines.

　　1. Common gas types and their characteristics



Currently, commonly used plasma cutting gases include air, nitrogen, oxygen, argon, and their mixtures (such as argon-hydrogen mixtures, nitrogen-oxygen mixtures, etc.). Different gases are suitable for different materials, thicknesses, and cutting requirements.



1. Compressed air: The most common and economical choice, suitable for cutting various metals such as carbon steel, stainless steel, and aluminum, especially suitable for medium and thin plate cutting. Air as a gas source is convenient and easy to obtain, but the disadvantage is that the cutting surface is prone to oxidation, affecting the welding performance.



2. Nitrogen (N₂): Suitable for cutting stainless steel and aluminum, it can achieve good cutting surface quality, reduce oxidation, and is suitable for workpieces that require subsequent welding or painting. However, the cost is relatively high.



3. Oxygen (O₂): Mainly used for cutting carbon steel, it can increase cutting speed and thickness. However, when using oxygen, attention must be paid to controlling the current and pressure, otherwise, it is easy to cause overburning of the切口 or severe oxidation.



4. Argon (Ar) and argon-hydrogen mixture (Ar-H₂): Suitable for cutting high-alloy materials such as stainless steel, copper, and aluminum, and performs exceptionally well in fine cutting and high-quality surface requirements. However, due to the certain danger of hydrogen, special attention must be paid to safety issues.



Factors to consider when selecting a gas



1. Material type to be cut: Different materials react differently to gases. For example, oxygen gas is suitable for carbon steel, while nitrogen is more suitable for stainless steel.



2. Cutting thickness: Thin plate cutting generally requires air or nitrogen, while thick plate cutting may require mixed gases or gases with higher ionization ability, such as argon-hydrogen mixtures.

　　3. Cutting quality requirements: In cases where high cutting surface smoothness is required, nitrogen or argon and other inert gases should be selected; if the cutting surface requirements are not high, air can be used to reduce costs.

　　4. Equipment compatibility: Different models of plasma cutting machines have different adaptability to gases. When selecting a gas, refer to the equipment manual to ensure that the gas matches the equipment parameters.



5. Economy and safety: Some gases (such as hydrogen) have good cutting effects but pose safety hazards; while air is cheap but has slightly lower cutting quality, a balance must be made between cost, efficiency, and safety.



Conclusion

　　In summary, choosing the appropriate plasma cutting gas is not a simple matter. It requires comprehensive consideration of factors such as material type, thickness, cutting quality requirements, equipment performance, and cost. In actual operation, it is recommended to perform trial cuts based on specific cutting tasks to find the most suitable gas type and parameter combination. By reasonably selecting the gas, not only can cutting efficiency and quality be improved, but the service life of the equipment can also be extended, production costs can be reduced, and overall production efficiency can be enhanced.



Correctly selecting plasma cutting gas is a key step in achieving efficient and high-quality cutting, and it is an important skill that every metal processing professional must master.