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Laser cutting effect gas selection detailed comparison (air, oxygen, nitrogen)

As we all know, the commonly used gases for laser cutting are air, oxygen and nitrogen. When cutting different materials with laser
The required auxiliary gas is often different.

In this issue, we will talk about the differences between air, oxygen and nitrogen, and show the cutting effect and efficiency respectively:

1. Air

【Air cutting is mainly applicable】Stainless steel, carbon steel, aluminum plate, brass and other materials cutting.

Because of its low cost, air cutting only needs an air compressor and the electricity consumption of the equipment itself, so it is widely loved by laser processing customers.
But cutting also has some disadvantages.

  • First, burrs may occur on the cut surface, and as the thickness increases, the burrs become more obvious, requiring secondary processing and cleaning, which will reduce the production efficiency of the entire product.
  • Second, the cut surface will turn black, which will affect the quality of the product. Therefore, for customers who do not require high cross-section smoothness and color, and pursue efficiency, air can be used for cutting.
  • We used a 20,000-watt air cutter to cut 14mm and 25mm carbon steel plates respectively. The bottom of the 14mm carbon steel plate has almost no burrs, and the finished product is better, while the effect of the 25mm carbon steel plate is obviously slightly worse than that of the 14mm carbon steel plate.

2. Oxygen

【Oxygen cutting is mainly applicable】Carbon steel, stainless steel, electroplated steel, copper and other materials cutting.

Oxygen cutting is the most common and traditional way of cutting.
The chemical reaction heat of oxygen and iron element promotes the heat absorption and melting of metal, which can greatly improve the cutting efficiency, realize the cutting of thicker materials, and significantly improve the processing capacity of the laser cutting machine.
Compared with air cutting, oxygen cutting has a smoother section, and the effect will be better when cutting thicker plates.

The disadvantage of oxygen cutting is that when cutting, due to the presence of oxygen, an obvious oxide film will be produced on the end face of the cut, making the cut section black, and cutting with oxygen will have a quenching effect on the material around the cut surface, increasing the hardness of this part of the material. Hardness has a certain impact on subsequent processing.

The effect of oxygen cutting 14mm carbon steel plate

The effect of oxygen cutting 25mm carbon steel plate

3. Nitrogen

【Nitrogen cutting is mainly applicable】Stainless steel, aluminum, carbon steel, brass and other materials cutting.

When nitrogen is used as the auxiliary gas for cutting, nitrogen will form a protective atmosphere around the molten metal to prevent the material from being oxidized, thereby ensuring the quality of the profile.
The end surface of the material cut with nitrogen gas is of good quality, does not contain any impurities, and the cut end surface is the natural color of metal.
This end face is very receptive to powder coating and also ensures a proper welding surface. Usually no secondary operations are required.

Nitrogen also has its disadvantages, because it does not chemically react with metals, does not generate reaction heat, and its cutting ability is not as good as that of oxygen. Moreover, the nitrogen consumption of nitrogen cutting is several times larger than that of oxygen, and the cutting cost is higher than that of oxygen cutting.
When using nitrogen cutting, we need to pay attention to that the change of gas flow has a great impact on cutting. In the case of ensuring the cutting gas pressure, we must ensure that the gas flow is sufficient.

The effect of nitrogen cutting 14mm stainless steel plate

The effect of nitrogen cutting 25mm stainless steel plate

4. Comprehensive analysis

 

We used air, nitrogen, and oxygen to cut 14mm and 25mm carbon steel plates and stainless steel plates, respectively, and the data are shown in the figure below.

 

Combining the above cutting effects, the conclusions are as follows.

  • If the carbon steel plate ≤ 20mm is cut, there is little difference between cutting the finished product with air and oxygen, but the cutting efficiency of air will be higher.
  • If cutting a carbon steel plate ≥ 25mm, to ensure the cutting effect, it is more appropriate to use oxygen for cutting, or adjust the power to a higher level when cutting with air.
  • When cutting materials such as stainless steel and aluminum, in order to ensure that the end face is smooth and not oxidized, it is necessary to use nitrogen for cutting.
  • On the premise of not considering the effect of the finished product, but only considering the cost, the cost of nitrogen is higher, followed by oxygen and air.

To sum up, if you want to find the auxiliary gas suitable for your model, you have to consider multiple factors such as equipment power, cutting materials, and cutting costs.

 

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