What are the effects of the use of shielding gas in laser welding on processing?

When laser welding is used, there are many factors that affect the quality of the finished part. For example, the shielding gas affects the weld formation, weld quality, weld penetration and weld width. The shielding gas will have a positive effect on the forming of the material in most cases, but there will also be a few negative effects.



The use of shielding gas has a positive effect on processing:


1. Selecting the appropriate gas type can effectively prevent the molten pool from being oxidized;


2. Selecting the appropriate gas flow rate can largely avoid spatter during welding;


3. Correctly blowing in the protective gas can make the molten pool more uniform and the weld more beautiful;


4. Blowing the shielding gas uniformly can reduce the occurrence of pores in the welding pool.


According to the different welding materials, selecting the appropriate gas type, gas flow rate and blowing method can achieve the ideal welding effect. However, when the shielding gas is used improperly, it will also have an adverse effect on welding.



Negative effects of shielding gas use on processing:


1. Improperly blowing shielding gas will cause uneven weld seam and prominent weld height;


2. The wrong type of gas may cause chemical reaction of the material in the weld, which will seriously affect the firmness of the weld;


3. Wrong gas blowing will cause oxidation of the welding material, affecting the appearance and quality of the finished product;


4. Blowing into the shielding gas will have a certain influence on the penetration depth of the weld, especially when welding thin plates, it will reduce the penetration depth of the weld.



The common protective gases in laser welding are generally nitrogen and argon. Nitrogen will chemically react with aluminum alloy, carbon steel and other metals at high temperature to produce oxides, which increase the brittleness of the material but reduce the toughness. Generally, it is only used in some special occasions. Argon is an inert gas, and it is difficult to chemically react with metal materials. Because of its low cost, it is used as a shielding gas for conventional laser welding.