MIG Gas: Understanding the Basics

While stick welding necessitates numerous stops to swap out electrodes, MIG welding with shielding gases results in cleaner, quicker welds without interruptions for electrode changes. Using shielding gases may reduce cleanup time and boost productivity, but knowing which gas is best for MIG welding and how it behaves in this application is essential. The primary goal of a MIG shielding gas is that it protects the molten weld pool from atmospheric oxygen, hydrogen, and nitrogen. The reactivity of these components in the weld pool may cause several issues, such as excessive spatter and porosity in the weld bead, which leads to weaker welds. Metal inert gas welding (MIG) ceases to be so if carbon dioxide or oxygen is in the process of introduction. Metal-active gas welding, or MAG welding, is the result. The reason for this is that CO2 and O2 are both reactive gases. While inert shielding gases like helium or argon are used for MIG welding, active gases are used for MAG welding.

Carbon dioxide (CO2) is the abundantly available gas in the atmosphere and one of the few that may be utilized without adding an inert gas like argon or helium. So long as project expenses are a concern, going with CO2 is the best option. Pure CO2, often called 100% CO2, is helpful for thick welding materials because of its high weld penetration. However, when used alone, CO2 is restricted to the short circuit welding process and results in a lesser stable arc and more spatter than when coupled with other gases (termed “mixed gases”). When the weld’s appearance is unimportant, or it will be hidden, such as on the bottom of a vehicle, pure CO2 is an excellent choice for the welding process. The cleanup process after welding is also more labour-intensive.


Butt and fillet welds benefit from argon’s shallower penetration. The curve is also very soft and natural looking. Pure argon is required for welding non-ferrous metals such as titanium, aluminium, and magnesium. Argon is best when combined with hydrogen, helium, or oxygen. Because of this, arc features are accentuated, and metal transfer is facilitated. Weld quality and appearance may both be improved by using mixed gases. Various possibilities exist, from 75% to 95% argon to 5-25% carbon dioxide.

Compared to just CO2, their arc stability and splatter are reduced. Welds created using the spray transfer method that uses mixed gases are more aesthetically pleasing and productive. Low-alloy types of stainless steel and carbon metals may be welded successfully using argon/carbon dioxide combinations. However, greater CO2 levels may lead to more splashing, so consider that.

Just as crucial as choosing the suitable gas is deciding what consumables to connect to your MIG gun. Protecting the weld pool from the ambient air is the responsibility of the diffuser, contact tip, and nozzle. There is a danger of insufficient shielding gas reaching the weld pool if the diffuser is clogged with a spatter or the nozzle is too small. It may cause spatter, porosity, and even contaminated welds when air pockets are introduced into the gas.

When shopping for MIG shielding gas gun accessories, look for ones that stay clear of splatter. You may trust your shielding gas protection, as the nozzle hole is large enough. Nozzles with integrated splatter protection are available from several manufacturers. It can double the diffusion of gas by two, resulting in a more steady flow of gas. Choosing which consumables to buy does need some thought and analysis. And also the current task at hand and your list of operational priorities.

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