Laser welding machine welding often use inert gases for protection, inert gases, also known as rare gases, they are colorless and tasteless, it is difficult to chemical reaction with other substances, because they are chemically inactive, so the welding is often used to isolate them from the air, through the nozzle mouth to a certain pressure to reach the surface of the workpiece, to avoid some of the gases in the air on the weld caused by oxidation.
The role of shielding gas
1. avoid oxidization of the workpiece in the welding process.
2. Improve the beauty of the welded seam after molding.
3. to prevent porosity problems.
4. Expand the laser utilization rate of the laser welding machine. 5.
5. Reduce the spattering of the focusing lens during the welding process of the laser welding machine.
Types of shielding gas
Protective gas will provide favorable conditions for the formation of the weld, when the welded material exists surface oxidation, need to use protective gas; when the welded material does not care about the surface oxidation, you can also not use the gas for protection. There are three types of maintenance gases most used in laser welding machines, namely helium, argon and nitrogen.
1. Argon
Argon is one of the most cost-effective protective gases, laser welding in the most used is it, because the activity of argon is very low, almost no chemical reaction with common metals, cheap, dense, can effectively protect the weld.
2. Nitrogen
Nitrogen is one of the most affordable protective gases, but due to metallurgical problems, it is not suitable for welding certain types of stainless steel, there may also be porosity, so it is not suitable for all metals as a welding protective gas, and stainless steel is the most common material, there are limitations.
3. Helium
Helium is one of the most expensive protective gases, but also the most useful laser welding in a protective gas, better than argon and nitrogen protection, can make the laser without obstruction directly to the surface of the workpiece, but the use of helium is more expensive.
Protective gas use safety
1. Move the gas tank smoothly when using.
2. Set the shielding gas first and then turn on the laser welding machine.
3. The user should stand at the side of the nozzle and slowly open the valve of the gas cylinder.
4. The way of blowing in the protective gas can be chosen according to the situation, and it is generally recommended to use the way of blowing in the side of the side shaft.
5. Keep the gas away from fire source and avoid high temperature or exposure to sunlight when storing.
Although the shielding gas is invisible, it plays an important role and affects the welding quality. In the choice of gas, on the one hand, can be combined with the welding material, location, method, cost and effect of factors such as comprehensive consideration, on the other hand, you can use different gases for welding test, and ultimately choose the laser welder gas suitable for their use.
