Which shielding gas for mig welding

You need to evaluate your welding goals and your welding applications in order to choose the correct one for your specific application. Consider the following as you make your selection:. Each provides unique benefits and drawbacks in any given application. It is the only one that can be used in its pure form without the addition of an inert gas.

CO2 is also the least expensive of the common shielding gases, making it an attractive choice when material costs are the main priority.

Pure CO2 provides very deep weld penetration, which is useful for welding thick material. However, it also produces a less stable arc and more spatter than when it is mixed with other gases.

It is also limited to only the short circuit process. For companies that place an emphasis on weld quality, appearance and reducing post-weld clean up, a mixture of between 75 — 95 percent Argon and 5 — 25 percent CO2 may be the best option.

It will provide a more desirable combination of arc stability, puddle control and reduced spatter than pure CO2. Choosing the consumables that provide continuous and even gas delivery is also a very important aspect to consider in your MIG welds. Be sure to evaluate your project goals in order to select the right gas for the weld at hand.

The four most common shielding gases used in MIG welding are carbon dioxide, argon, oxygen, and helium. Each has their unique benefits, and drawbacks, in any given implementation.

They will most likely provide several options, ranging from the best gas option to gas that will provide the minimum acceptable welds, as well as their prices.

However, your MIG welder may have an electrode and gas recommendation guide on the inside panel which will provide you a list of several options. CO2 is, by far, the most common and is one of the only gases that can be used in its pure form without needing the addition of an inert gas, such as argon or helium. Because of this, CO2 is the most cost effective option and a good choice if project costs are a priority. Pure CO2 is good for projects where the aesthetics of the weld are either not important, or the weld cannot be seen, such as on the underside of a car.

Post weld clean up is also a little more involved. Argon allows for narrower penetration, which is handy for butt and fillet welds.

It also boasts a smooth and relatively fluid arc. Argon is also often mixed with hydrogen, helium, or oxygen. For stainless steels there are also gases available containing small amounts of hydrogen H2.

The normal gas for TIG welding is argon Ar. For instance, the addition of hydrogen gives a similar, but much stronger, effect as adding helium. However, hydrogen additions should not be used for welding martensitic, ferritic or duplex grades. Alternatively, if nitrogen is added, the weld deposit properties of nitrogen alloyed grades can be improved.

Oxidizing additions are not used because these destroy the tungsten electrode. Recommendations for shielding gases used in TIG welding of different stainless steels are given in the table. For plasma-arc welding, the gas types with hydrogen additions in the table are mostly used as plasma gas, and pure argon as shielding gas. Carbon Dioxide CO2 : It is the most common of the reactive gases used in MIG welding especially in Nigeria and the only one that can be used in its pure form without the addition of inert gas.

CO2 is also the least expensive of the common shielding gases, making an attractive choice when material costs are the main priority. Pure CO2 provides very deep weld penetration, which is useful for welding thick material; however, it also produces a less stable arc and more spatters than when it is mixed with other gases.

It helps improve weld quality. Oxygen and argon are mostly used for spray transfer on stainless steel to help generate a steady arc. However, the increased fluidity of the weld pool can make out-of-position welding an issue.

Similar to pure argon, helium is mostly used with non-ferrous metals and also with stainless steel. By adjusting these ratios, the travel speed, bead profile, and penetration are changed. You have to calculate the productivity increase value versus the increased gas cost. When it comes to welding stainless steel, helium is mostly used in a tri-combination of carbon dioxide and argon. These two gas mixtures provide users with different benefits and drawbacks. The one you shall use relies on your specific welding purpose.

A blend lets you work fast and, therefore, your finished projects will have a much cleaner appearance. Nonetheless, there are two issues with a high argon mixture. The other issue is that a higher concentration of argon reduces the rate of penetration of the arc. It produces a deeper penetration in the connecting metals and creates a strong, larger bead. It makes the arc crackle and pops more, forming spatter. It also forms a mild amount of smoke and fumes when welding.

Higher spatter implies that more cleaning is needed after the job is done. With stainless steel, things get more costly when more helium is mixed with argon and carbon dioxide or Oxygen. For gas flow setting and experiment, contact the manufacturer to see what will work best for you and one that will be convenient.

Cameron grew up in Allentown, Pennsylvania, a once-proud steel town on the Lehigh River, where he got a taste of TIG welding in his high school shop class. His interests include scuba diving, sculpture, and kayaking. Water Welders is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you.

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