Shielding gas for laser welding machine
The laser welding machine will use shielding gas during the welding process. The shielding gas is injected through the nozzle to reach the surface of the workpiece with a certain pressure. However, many people do not know why the shielding gas is used and which gases can be used for laser welding. What are their specific functions?
Shielding gas for laser welding machine:
1. Helium is not easy to ionize (high ionization energy), which allows the laser to pass smoothly, and the beam energy reaches the surface of the workpiece without hindrance. This is the most effective shielding gas used in laser welding, but it is more expensive. 2. Argon gas is cheaper and denser, so the protection effect is better. However, it is susceptible to high-temperature metal plasma ionization, which shields part of the beam from being directed to the workpiece, reduces the effective laser power for welding, and also damages the welding speed and penetration. The surface of the weldment protected by argon is smoother than when protected by helium. 3. Nitrogen is the cheapest shielding gas, but it is not suitable for welding certain types of stainless steel, mainly due to metallurgical problems, such as absorption, which sometimes produces pores in the overlap area.
The role of protective gas:
One protects the focusing lens from metal vapor contamination and liquid droplets splashing The shielding gas can protect the focusing lens of the laser welding machine from metal vapor pollution and liquid droplet sputtering. Especially in high-power welding, because the ejection becomes very powerful, it is more necessary to protect the lens at this time. The second shielding gas is very effective in dissipating plasma shielding produced by high-power laser welding The metal vapor absorbs the laser beam and ionizes into a plasma cloud, and the shielding gas around the metal vapor is also ionized by heating. If there is too much plasma, the laser beam is consumed by the plasma to some extent. Plasma exists on the working surface as the second kind of energy, which makes the penetration depth become shallower and the weld pool surface becomes wider. Increase the electron recombination rate by increasing the three-body collision of electrons with ions and neutral atoms to reduce the electron density in the plasma. The lighter the neutral atom, the higher the collision frequency, and the higher the recombination rate. On the other hand, only the shielding gas with high ionization energy will not increase the electron density due to the ionization of the gas itself.
Three protective gases can protect the workpiece from oxidation during welding After reading the above introduction about the shielding gas of laser welding machine and what is its function, I think everyone must have a certain understanding of shielding gas for laser welding machine. I hope that the above content can help to actually use or will use laser You of the welding machine bring some help.