How to use auxiliary gas correctly
When using a laser welding machine, the auxiliary gas will affect the weld formation, weld quality, weld penetration and penetration width. In most cases, blowing the auxiliary gas will have a good effect on the weld, but it may also cause damage. Positive effect of auxiliary gas
1) The correct blowing of auxiliary gas will effectively protect the welding pool to reduce or even avoid oxidation; 2) The correct blowing of auxiliary gas can effectively reduce the splash generated during the welding process; 3) The correct blowing of auxiliary gas can promote the uniform diffusion of the weld during the solidification process, and make the weld shape uniform and beautiful. 4) The correct blowing of auxiliary gas can effectively reduce the shielding effect of the metal vapor plume or plasma cloud on the laser, and improve the effective utilization of the laser; 5) The correct blowing of auxiliary gas can effectively reduce the weld. As long as you choose the correct gas type, gas flow and blowing method, you can get the desired effect. However, improper use of auxiliary gas can also adversely affect welding. Negative effects of auxiliary gas 1) Incorrect blowing of auxiliary gas may cause deterioration of welds: 2) Choosing the wrong gas type may cause cracking of the weld, and may also reduce the mechanical properties of the weld; 3) Choosing the wrong blowing flow rate may cause more serious welding oxidation (too much or too small flow rate). This may also cause the weld pool metal to be seriously disturbed by external forces, and cause the weld to collapse or form unevenly; 4) Choosing the wrong blowing method will cause the welding seam to fail to achieve the protection effect, or even basically no protection effect, or adversely affect the formation of the welding seam; 5) Blowing in shielding gas will have a certain effect on the weld penetration, especially when welding thin plates, it will reduce the weld penetration. How to use auxiliary gas correctly for laser welding machine? Type of auxiliary gas The auxiliary gases commonly used in laser welding machines are mainly N2, Ar, He, and their physical and chemical properties are different, so they have different effects on welding.
1. Nitrogen N2
The ionization energy of N2 is moderate, higher than Ar and lower than He. Under the action of the laser, the ionization degree is moderate, which can reduce the formation of plasma clouds and improve the effective utilization of the laser. Nitrogen can chemically react with aluminum alloy and carbon steel at a certain temperature to form nitrides, which will increase the brittleness of the weld, reduce the toughness, and have a greater adverse effect on the mechanical properties of the weld. Therefore, it is recommended not to use nitrogen to protect aluminum alloy and carbon steel during welding.
The nitride produced by the chemical reaction between nitrogen and stainless steel can increase the strength of the welded joint, which will help improve the mechanical properties of the weld. Therefore, nitrogen can be used as a shielding gas when welding stainless steel.
2. Argon Ar The ionization energy of Ar is low, and the ionization degree is high under the action of laser, which is not conducive to controlling the formation of plasma cloud, and has a certain influence on the effective utilization of laser. However, Ar has very low activity, and it is difficult to chemically interact with common metals. In addition, the cost of Ar is not high. In addition, the density of Ar is higher. It is conducive to sinking to the top of the welding pool, and can better protect the welding pool, so it can be used as a conventional shielding gas. 3.Helium It has the highest ionization energy, and the ionization degree is very low under the action of laser, which can well control the formation of plasma cloud. Laser can work well on metals. And its activity is very low, and basically does not chemically react with metals. It is a good shielding gas for welding seams, but the cost of helium is too high. Generally, mass-produced products do not use this gas. It is usually used for scientific research or products with high added value.