What Is a Shielding Gas?

Shielding gas refers to the gas used to protect metal droplets, molten pools and weld areas during welding. It protects high-temperature metals from external gases. [1]

Shielding gas refers to the gas used to protect metal droplets, molten pools and weld areas during welding. It protects high-temperature metals from external gases. [1]
Chinese name
Protective gas
Foreign name
protective gas; shedling gas
Types of
Special gas for electronics
Function
Protects metal droplets during welding

Protective gas category

Shielding gases can be divided into two categories: inert gases and reactive gases. Inert gases refer to helium and argon, which do not react with the molten weld at all and are used for MIG welding (metal-inert gas arc welding). Reactive gases generally include carbon dioxide, oxygen, nitrogen and hydrogen. These gases participate in the welding process by stabilizing the arc and ensuring that the material is smoothly transferred to the weld. When it accounts for most of the gas, it will destroy the weld, but a small amount can improve the welding characteristics. It is used for MAG welding (metal-active gas arc welding). ). [2]

Protective gas performance

Thermal conductivity and heat transfer are important properties of the protective gas, and they need to be denser than air and have a lower flow rate than air. High voltage can increase the degree of ionization, which makes welding arc ignition easier. The shielding gas can be a single gas or a mixture of two or three gases. In laser welding, the shielding gas can also absorb an important part of the laser energy, preventing the formation of plasma on the upper layer of the electric welding.

Protective gas effect

Shielding gas is used to protect metal droplets during welding, which often has an important effect on the productivity and quality of welding. Shielding gas prevents oxidation of molten welds during solidification, and also blocks impurities and moisture in the air. It may reduce the corrosion resistance of welds by changing the geometric characteristics of the welds, generate porosity and weaken the durability of welds Sex. Shielding gas will also cool the torch. [3]

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