MIG welding weld results, productivity, arc behavior and costs significantly rely on the gas used in this process. It is crucial to choose the right gas for the work at hand. So, what type of gas is used for MIG welding?
A mixture of 75% Argon and 25% CO2 gas is the most common gas used for MIG welding. Other gasses, including oxygen and helium, are also used depending on the metal type. For example, helium is suitable for MIG welding thick aluminum.
Now, let’s learn about some options and discuss how to get the best result from MIG welding by selecting the preferred MIG welding gas for your jobs.
What type of Gas is Used for MIG Welding?
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Before choosing a welding gas, evaluate your welding applications and goals. Argon, CO2, Helium and Oxygen is used in the MIG welding process. Each gas type has its own set of benefits and drawbacks when used with different metals.
Argon Gas
Air is less dense than argon and protects the molten pool from contamination of atmospheric gas by settling over the joints. Moreover, ionizing argon is also easy, making it effective in handling long arcs at low voltages.
Sadly, pure argon is unsuitable for welding stainless steel and steel.
When welding steel, the arc’s outside edges remain cool, giving you reduced and narrow penetration. In addition, the filler material stays on top of the steel, causing a “tall” bead. In this case, a blend of Ar and CO2 or Ar and O2 is a good solution.
While, 100% argon gas is a good choice for non-ferrous welding materials named aluminum, nickel, copper, titanium, magnesium, etc. The cathodic cleaning action of argon removes oxide from the metal surface with DCEP polarity, making it essential for welding aluminum.
Benefits:
- Lessons spatter
- Generates high productivity
- Best gas for non-ferrous metals
- Boasts a smooth and relatively fluid arc
- Aids in metal transfer
Drawbacks:
- Unsuitable for stainless steel and steel
Carbon Dioxide Gas
One of the most common reactive gasses in MIG welding is carbon dioxide. It can be used in MIG welding in its 100% pure form, and adding a noble gas is entirely unnecessary. Moreover, it is the cheapest option among the shielding gasses. When material cost gets the highest preference, this gas is the most appealing choice.
Deep weld penetration is the best offer of Co2 gas. It is beneficial when you need to weld thicker metals.
Welding non-ferrous metal is quite difficult using carbon dioxide gas. You can weld steel or stainless steel with it. If your project requires welding thick metal, don’t hesitate to use pure CO2. However, when using 100% Co2, make sure to use metal-transfer and short-circuit welding mode.
Benefits:
- Most effective option if project cost is the priority
- It offers a deep welding penetration
- Weld thick materials efficiently
- Suitable for ferrous materials
- Cheapest
Drawbacks:
- Delivers more welding spattering
Oxygen
Oxygen is a reactive gas generally blended in a small amount with Ar or Co2. The welding effects can dramatically be changed due to a small amount of oxygen. Most of the time, the blending ratio is 9% or less to improve penetration, weld pool fluidity and arc stability in a low alloy, stainless steel and mild carbon.
In addition, while creating a stable arc, it offers limited spatter.
But oxygen has a few disadvantages. Higher oxygen levels may increase puddle fluidity, making the welding process hard. Moreover, oxygen is another prime reason for the oxidation of the metal. That is why I recommend not to use it with copper, magnesium, aluminum, or other exotic metals. Again, remember not to use oxygen as a bare gas.
Benefits:
- Boosts weld pool fluidity when used with Ar and Co2
- Improves weld quality
- Help stainless steel to generate a steady arc
Drawbacks:
- Higher levels of use cause puddle fluidity
Helium Gas
The performance of helium is similar to pure argon. However, you can’t use it as an alternative to argon gas. Helium is a good choice for stainless steel and non-ferrous materials. A deep and broad penetration profile is helium gas’s best feature, making it an ideal choice for thick metals. The ratio is between 25 and 75% helium and 75 and 25% argon.
When these ratios get adjusted, the penetration, bead profile and travel speed change simultaneously. Helium creates a “hooter” arc, enabling higher productivity rates and quicker travel speeds.
But helium is an expensive option compared to argon. A higher flow rate is also necessary to complete the MIG welding job. When welding steel or stainless steel, helium gas is combined with Argon and Carbon dioxide.
Benefits:
- Generates a deep penetration profile
- Works well with thick materials
- Allows higher productivity rates
- Best choices for non-ferrous and thicker parent metal
- Enables quicker travel speed
Drawbacks:
- It needs a higher flow rate
FAQ
What gas do you use for MIG welding?
Argon, Carbon dioxide, Oxygen and helium are the most commonly used gas for MIG welding. Each gas type has exceptional advantages and disadvantages. You must choose the gas type based on the welded metals and project type.
Can you MIG weld 100% argon?
Yes, you can MIG weld steel or stainless steel with 100% argon, but it is not recommended. The arc will be unstable when used 100% argon for steel welding. Also, 100% argon is prone to undercutting. Moreover, pure argon gas loses its ductility when used with steel.
Can you MIG weld without gas?
Technically, MIG weld without gas is impossible. But a flux core wire will be helpful in this case for MIG welding without gas. A slag will be created on the weld as soon as it cools. The weld puddle will be protected from different contamination by atmospheric gas by the slag.
Final Words
Hopefully, all your queries about “what type of gas is used for MIG welding” are resolved. 75% argon and 25% Co2 or 80/20 mixture is possibly the best option.
Also, you need to consider the welding metals before selecting the gas type. Make sure that you are getting the highest utilization of your gas flow. Thus, you can choose the right gas type for your MIG welding project and get the best result.