Technology

Key Essential Factors to Consider When Choosing a Shielding Gas

Shielding gas is a necessary component of several arc welding techniques. There are several shielding gases to select from, which might be perplexing for those new to welding. When choosing the correct gas, consider the welding method, material type, power supply, transfer mode, penetration, and cost.

What exactly is shielding gas?

Shielding gas are inert or semi-inert gases used during welding procedures to protect the weld quality and the material being worked on from oxygen, hydrogen, nitrogen, and water vapor.

The presence of oxygen, hydrogen, nitrogen, and water vapor in the environment can be hazardous to your weld and cause contamination and oxidation in molten metal. They also affect the welding process, influencing welding speed, weld penetration, surface form patterns, and other weld elements.

Using a shielding gas considerably enhances metal fabrication quality, delivering a clean and robust completed weld.

Factors to Consider when Choosing a Shielding Gas

Several factors influence the choice of shielding gas. The significance of each varies depending on the scenario. For example, MIG (GMAW) welding steel offers numerous shielding gas options. Still, when the cost is an essential consideration, CO2 will be the better choice than other argon mixtures, even though there is more spatter. Before choosing a shielding gas, consider the following:

Welding Procedure

The most prevalent arc welding techniques are the MIG (GMAW), the TIG (GTAW), the Flux Cores – Self Shielded (FCAW-SS), the Flux Cores – Gas Shielded (FCAW-GS), and the Stick welding. Since the flux comes into contact with the electrode, Flux Cored – Self Shielded do not require shielding gases. Despite their convenience, self-shielded processes have some downsides due to the lack of additional gas needed. Self-shielded processes result in a less stable arc, which causes excessive spatter. In addition, to the spatter, removing the protective coating of slag from the weld bead requires additional time and work.

Type of Material

Shielding gas selection depends on the material. It is usually advisable to use shielding gases when welding, but welding with incompatible gases can result in inferior welds with contamination and flaws. An excellent example of this is argon-hydrogen gas. Adding hydrogen to argon for TIG welding stainless steels resulted in deeper welds. If you use the same gas to TIG weld aluminum, you will have porosity and holes spread throughout the weld. One of the first things to look for is the gas’s compatibility with the material.

Energy Source

Welders vary significantly from one another. One of the key advantages of modern, inverter-based technologies is the ability to adjust the arc in novel and creative ways. One illustration is the auto set function found in the Millermatic and Multimatic series from Miller Electric. Each setting category has a recommended gas mixture. This is because Miller’s weld experts designed each set to work with the designated gas or gas blend. The end product is a well-tuned arc that welds effectively and with little effort. Welders should use a manual or door chart explaining the recommended gas mixes.

Cost

When choosing a shielding gas, price is one of the main deciding criteria. When used for TIG and wire welding aluminum and stainless steel, helium is more costly than argon. For wire welding steel, 100% CO2 is more economical than any argon-CO2 mixture. There is always a cost associated with welding using less expensive gases, regardless of the material or technique. CO2 tends to generate more spatter, which requires more time to clean up and raises the cost of production. CO2 is usually the best choice if splatter or additional time is not an issue.

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