Dry goods sharing of mixed gas selection during welding

Wed, 22 May 2024 01:07:26 GMT

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In welding operations, selecting the appropriate gas mixture is the key to ensuring welding quality and efficiency. Here are some dry sharing tips on selecting mixed gases to help you make more direct and accurate decisions.

The role of common welding gases
Argon (Ar): commonly used in TIG and MIG welding because it can provide stable arcs and clean welds.
Oxygen (O ₂): Adding a small amount of oxygen during certain welding processes can increase the temperature and fluidity of the molten pool.
Carbon dioxide (CO ₂): Commonly used in MIG welding when mixed with argon gas, it can improve welding speed and penetration depth.
Helium (He): Although it has a high cost, it can increase the arc temperature and welding speed, making it particularly suitable for welding materials such as aluminum alloys.

Mixed gases are mainly divided into two categories: binary mixtures and ternary mixtures.

Binary mixture
A binary mixture is a gas system formed by mixing two gases in a certain proportion. In welding, common binary mixtures include the following:

1. Argon+Oxygen: Adding an appropriate amount of oxygen to argon can effectively improve arc stability and refine molten droplets. The oxygen combustion characteristics can increase the temperature of the metal in the molten pool, promote metal flow, reduce welding errors, make the weld bead smoother, accelerate welding speed, and improve welding efficiency. This mixed gas is suitable for welding various thicknesses of carbon steel, low alloy steel, and stainless steel.

2. Argon+carbon dioxide: Carbon dioxide can improve welding strength and corrosion resistance, but pure carbon dioxide protects against excessive splashing. Mixing stable argon gas can effectively reduce metal splashing rate. This mixed gas is also suitable for welding carbon steel and stainless steel.

3. Argon+Hydrogen: Hydrogen is a reducing combustion gas that can increase arc temperature, accelerate welding speed, prevent underflow, reduce the formation of CO pores, and prevent welding defects. This mixed gas has good welding effects on nickel based alloys, nickel copper alloys, and stainless steel.

Ternary mixture
A ternary mixture is a gas system composed of three gases mixed in a certain proportion. In welding, common ternary mixtures include the following:

1. Argon+oxygen+carbon dioxide: This ternary mixture combines the advantages of argon+oxygen and argon+carbon dioxide binary mixtures, which can reduce welding spatter, improve the fluidity of the melt pool, reduce bubble generation, and improve weld quality. It can be used for welding different thicknesses of carbon steel, low alloy steel, and stainless steel, with a wide range of applications.

2. Argon+helium+carbon dioxide: This mixture can improve arc stability and operability, as well as increase the temperature of the molten pool, improve fluidity, and enhance welding quality and speed. Due to the inert nature of helium (He) and its inactive chemical properties, its oxidation effect on the weld seam is small. This mixed gas is commonly used in various types of short-circuit arc welding and overwelding.


Pay attention to the proportion of mixed gases
The proportion of mixed gases directly affects the welding effect. For example, in a mixture of argon and carbon dioxide, an increase in the proportion of carbon dioxide can improve welding speed and penetration depth, but it may also increase the risk of spatter and porosity. Therefore, it is necessary to adjust the proportion of mixed gases according to specific needs.

When selecting a mixed gas, factors such as the type and characteristics of welding materials, welding methods, and welding process requirements need to be considered. Different mixed gases have different characteristics and applicable ranges, which need to be selected according to specific situations.