Oxygen assisted combustion increases heat and improves cutting thickness. The advantage is low cost, mainly used in carbon steel

. Nitrogen does not assist combustion, melting zone temperature is low, suitable for processing aluminum, brass and other low melting point materials. nitrogen

The gas protected slit is not oxidized, and can also be used for non-oxidized cutting of stainless steel. The processing range is shown in Table 1.
Table 1 Laser cutting processing range
Material auxiliary gas maximum cutting thickness /mm
Carbon steel O2 16 ~ 20
Stainless steel O2 6 ~ 10
Stainless steel N2 8 ~ 12
Duralumin N2 4 ~ 8
Soft aluminum N2 2 ~ 6
Brass N2 3 ~ 4

Second, nitrogen cutting elements
Nitrogen cutting because of its own characteristics, cutting conditions and oxygen cutting have obvious differences. After more than two years

Practical application, we have gradually mastered the elements of nitrogen cutting through practice.
1. Gas parameters
The air pressure and nozzle determine the surface roughness and burr of the cutting surface. Appropriate increase in air pressure is conducive to slag discharge, but

Too large will increase the surface roughness value. Nitrogen cutting has the following requirements for gas parameters: (1) air pressure

Nitrogen does not participate in combustion and is used to blow off liquid materials with a relatively low temperature, requiring (10 ~ 14) *105Pa

High air pressure. The pressure of oxygen cutting is generally not more than 4*105Pa. (2) Nozzle nitrogen using high pressure

A large nozzle diameter is required to ensure the air output. For example, for cutting 2mm thick stainless steel, use a nozzle for oxygen

HK10 (? 10mm), nitrogen requires HK15 (? 15mm). (3) Purity Nitrogen purity on cutting quality

It has a great effect (see Table 2), and the oxygen content affects the cutting quality. Moisture poses a danger to the laser

Therefore, the gas level should be guaranteed to be at least 4.5.
2. Cutting parameters
The cutting parameters and machining procedures are independent of each other, which facilitates the adjustment of parameters. Rich parameters can be used to control cutting

All aspects of the process are the key to determining the quality of the cut. Nitrogen cutting and oxygen cutting due to processing methods

The differences on the following cutting parameters have different requirements.
Table 2 Relationship between nitrogen purity and cutting quality
Gas Grade Gas purity (%) Oxygen content *10-6

Water content *10-6 cutting section surface quality
2.8 ≥99.8 ≤500

≤20 No oxygen, yellow surface
3.5 ≥99.95 ≤100

≤10 No oxidation, no luster
4.5 ≥99.995 ≤10

≤5 No oxidation, bright section
5.0 ≥99.9999 ≤3

≤5 Safe, no oxidation, shiny section
(1) Speed nitrogen cutting only relies on laser melting materials, takes a longer time, cutting speed than oxygen

Slow cutting.
(2) Power nitrogen cutting requires high power to ensure continuous melting of the village mass. It's always around 100%.
(3) Focus position nitrogen cutting completely depends on laser energy, focus down can enhance the beam energy, to

Get the focus close to the bottom of the plate. Oxygen cutting requires the focus to be on the surface of the plate.
(4) The conversion time from the perforating pressure to the cutting pressure when nitrogen is cut, the perforating pressure is 2*105Pa, and cut

There's a big difference in cut pressure. A sudden rise in pressure can easily cause the laser to break arc. Provides tens of milliseconds of buffering

Make the air pressure balance transition, ensure the cutting quality. Oxygen cutting perforation pressure and cutting pressure difference is very small

There is no need to provide this conversion time.
(5) Acceleration of the acceleration factor when cutting changes direction. Nitrogen cutting increases energy requirements, so

It is generally lower than 1m/s2, and decreases sharply with the increase of thickness. Oxygen cutting is generally about 1m/s2

And it does not change dramatically with thickness, but decreases slightly.
Third, the application of nitrogen cutting
Nitrogen cutting solves many processing problems in actual production, and expands the processing range to aluminum and yellow

Areas where oxygen cutting such as copper is difficult to process. The following describes its application in various materials and fields.
1. Carbon steel
Carbon steel is cut with oxygen. The surface temperature is very high due to carbon-assisted melting and oxygen-assisted combustion. When cutting tip

When the hole with acute Angle and diameter is less than the material thickness, too much heat is concentrated in a narrow area, so that the cutting quality is not

The law guarantees. Nitrogen does not assist combustion, coupled with the cooling effect, suitable for solving such processing problems

Enough to improve the quality of the product.
2. Stainless Steel
From cost considerations, cutting edge oxidation does not affect the use of oxygen cutting of stainless steel parts. But in stainless steel

The content of alloying elements such as Ni is large, the melt viscosity is large, the fluidity is poor, and the air pressure is low when the oxygen is cut

It is easy to lead to quality defects such as sticky slag. When welding stainless steel, the oxide layer seriously affects the welding quality, especially argon

Arc welding. Nitrogen cutting provides high quality non-oxidizing section, which meets the high requirements of stainless steel welding for cutting section

Please.
3. Aluminum, brass
Aluminum and brass have high reflectivity and low absorptivity to lasers, requiring high power to melt materials. And to match

A reflection absorption device is provided to prevent the uneven linear wave from reflecting back to the lens to protect the safety of the laser. Required nitrogen

Gas cutting.
Aluminum has a low melting point, and oxygen can be cut below 3mm thickness, but the quality is poor, and the section is hard.

Using nitrogen to cut the section smooth, 4mm thick can get no burr effect. Aluminum is very viscous

Combined with the thermal conductivity, the melt may have cooled before it had time to blow away, so it is prone to burrs

. By adjusting the focus, increasing the air pressure, and reducing the speed, the surface roughness value is reduced to ensure that the burr can be light

Easy to remove.
4. Etching
Etching is a special cutting with only 5% of the basic power. It only acts on the surface of the material, Lord

To etch the mark. Oxygen etching temperature height, sometimes the surface of the welding slag. Concentrated etching will also cause heat

The concentration causes damage to the surface of the part. Nitrogen etching is bright and does not damage the surface, and can be used for etching with higher requirements

The caption.
Iv. Conclusion
Oxygen cutting thickness, low cost, mainly used in carbon steel. The cooling and protective effects of nitrogen are improved

Cutting quality, and in the cutting of stainless steel, aluminum, brass achieved good results, to solve many processing difficulties

Question.
In addition, the characteristics of unassisted combustion can also be used to process special materials such as wood and plexiglass, which has a broad range

The application prospect of...

The Trojan nitrogen machine saves costs for enterprises and uses nitrogen more stably and conveniently!