First of all, nitrogen and argon protection can isolate oxygen, nitrogen, hydrogen, etc. in the air to prevent oxidation of the weld and the generation of pores;
Another function of using shielding gas is to protect the focusing lens from spatter damage generated during welding. However, now welding machines are equipped with protective lenses in front of the focusing lens. However, during high-power laser welding, the ejection becomes very powerful, so protecting the lens is necessary.
The third function of the shielding gas is to dissipate the plasma shield produced by high-power laser welding.
The continuous radiation of the laser to the molten pool will form a plasma cloud in the upper part of the molten pool, which limits the passage of the laser and has a scattering effect on the laser. If not restricted, it will affect the penetration depth and reduce the strength of the weld. During the laser welding process, the blowing of the protective gas onto the weld seam not only prevents the oxidation of the weld seam and the generation of pores but also blows away the plasma cloud and increases the absorption of laser energy by the molten pool. The gas used should have a large ionization energy and prevent the protective gas itself from ionizing and generating plasma. Thereby increasing the efficiency of the laser reaching the workpiece.
Helium has the smallest ionization and can quickly expel the rising metal vapor generated from the metal molten pool. Using helium as a protective gas can suppress the plasma to the greatest extent, thereby increasing the penetration depth and increasing the welding speed. In addition, it also It is also light and can escape, and it is not easy to cause pores. However, because it is more expensive, we consider it from the perspective of cost reduction. In addition, judging from our actual welding results, the effect of nitrogen and argon gas protection is also pretty good, so nitrogen and argon are used in more situations.
Riselaser Technology Co., Ltd. is a company that develops, manufactures, and sells dozens of industrial laser equipment such as handheld laser welding machines, handheld laser cleaning machines, CO2 laser marking machines, laser engraving machines, lithium battery laser welding machines, etc.