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Figure 9 Normal Cutting Speed
6.6 Cutting auxiliary gas
Consider from the following several aspects in the case of selecting type and pressure of cutting
auxiliary gas:
1) Generally, oxygen is used to cut ordinary carbon steel and thick red copper.
2) Generally, air is used to cut thin plates of thickness less than 2mm.
3) Generally, nitrogen is used to cut stainless steel, red copper, brass, aluminum plate, etc.
4) The higher the gas purity is, the higher the cutting quality will be. Purity for cutting low-carbon
steel plate shall be at least 99.6%, and recommended oxygen purity for cutting carbon steel
plate of thickness more than 12mm is above 99.9. Oxygen purity for cutting stainless plate
shall reach above 99.6%. The higher the oxygen purity is, the higher the quality of cutting
section will be. If cutting gas purity cannot reach the regulated indicator, it will not only
influence cutting quality, but also cause the pollution of lens.
6.6.1 Influence on cutting quality from auxiliary gas
Gas is conducive to heat dissipation and combustion supporting, blowing off melting stains and
improving quality of cutting surface.
➢ Influence on cutting from insufficient gas pressure
a. Melting stains on cutting surface.
b. Cutting speed cannot be increased, which influences efficiency.
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