What protective gas should I use for laser welding?

Type of protective gas

Commonly used laser welding protective gases are mainly N2, Ar, He, and their physicochemical properties are different, so the effect on the weld is also different.

1. Nitrogen N2—a welding protective gas of stainless steel

The ionization energy of N2 is moderate, higher than that of Ar, lower than that of He, and the degree of ionization is generally under the action of laser, which can better reduce the formation of plasma cloud, thereby increasing the effective utilization of laser. Nitrogen can react with aluminum alloy and carbon steel at a certain temperature to produce nitrides, which will improve the brittleness of welds and reduce the toughness, which will have a great adverse effect on the mechanical properties of welded joints.

Therefore, it is not recommend to use nitrogen.Protective Aluminum and carbon steel welds.The nitride produced by the chemical reaction between nitrogen and stainless steel can improve the strength of the welded joint and improve the mechanical properties of the weld.

Therefore, when welding stainless steel can use nitrogen as a shielding gas

2. Argon Ar—-high cost performance, the most conventional protective gas

The ionization energy of Ar is relatively low, and the degree of ionization is high under the action of laser, which is not conducive to controlling the formation of plasma cloud, which will have certain influence on the effective utilization of laser, but the activity of Ar is very low, and it is difficult to chemicalize with common metals.The reaction, and the cost of Ar is not high, in addition, the density of Ar is larger, which is favorable for sinking above the weld pool, and can better protect the weld pool.so it is a conventional shielding gas.

3. Helium He—the best but also the most expensive protective gas

He has the highest ionization energy and low ionization under the action of laser. It can control the formation of plasma cloud very well.So The laser can work well on metal, and the activity of He is very low, and it does not chemically react with metal.Very good weld protection gas, but the cost of He is too high, generally not used in mass production products, He is generally used for scientific research or products with very high added value.

Hope it is helpful for you.If you have any questions of machine,welcome to contact XT LASER.

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