Air :

The cost of air is very cheap and you only need to consider the electricity cost of the air compressor and the equipment itself. When cutting thin sheets, air cutting is efficient as well as nitrogen cutting. It is a cost-effective cutting method. But air cutting has obvious disadvantages. First of all, the air cutting surface will produce burrs, it will require the second processing and cleaning, which is not conducive to the entire production cycle. Second, the cut surface will turn black. 

Oxygen :

Oxygen cutting is the most common and traditional cutting method. It can improve cutting efficiency and facilitate management. The oxygen cost is much cheaper compared with nitrogen.  But with oxygen cutting, the oxide film is easy to stay on the cutting surface. If the product with oxide film is directly welded, the oxide film will naturally peel off with time going by. And the product will be virtual weled, the welding quality will not be good. 

Nitrogen :

Sometimes, the oxide film will stay on cutting surface when we choose oxygen as cutting gass. However, the nitrogen can prevent this and form non-oxidative cutting. The surface of non-oxidized cutting is generally white and can be directly processed by welding, spraying, etc.