TIG welding requires the use of shielding gas to protect the weld pool and the electrode from contamination. TIG itself stands for Tungsten Inert Gas welding, so you can imagine where inert gas comes from.
The type of gas you use in TIG welding can have a significant impact on the quality of the weld and on the appearance of the resultant product.
Choosing the wrong gas can lead to pores, cracks, beads with irregular shapes, or penetration that is uneven.
So, to help you out, I decided to share some expert tips on selecting and using the right gas for TIG welding.
In this post, I will be discussing different types of gas used in TIG welding that will help you find the perfect match for your needs.
You will be able to improve your welding technique and achieve picture-perfect results just by selecting the right gas.
So, let’s begin:
Contents
An In-Depth Look at the TIG Welding Gas
There are several types of gasses that are used in TIG welding. Each of these gasses comes with its own unique characteristics and uses. The most common of these gasses are Argon and Helium.
Let’s dive into the details of these gasses to know exactly what they are, and how they are used in TIG welding:
Argon
Argon is one of the most widely used inert gas for TIG welding. It gets the job done most of the time and is also readily available, which makes it the perfect choice for any TIG welder.
Argon doesn’t chemically react with any of the metals, the tungsten electrode, or the filler wire. Hence, there is zero risk of contamination, which makes it an excellent choice.
Adding to this, it is denser than air, which means it will settle over the weld pool and protect it from air contaminants, a perfect shielding gas.
Furthermore, it is easy to ionize which helps it maintain a stable arc, even when you are using an extended arc length.
You can also use this gas to weld aluminum, as it supports the cathodic cleaning action with AC voltage.
The best part is, Argon is much cheaper than other gasses and is easily available.
Types of Metals to Use On:
- Mild Steel
- Stainless Steel
- Aluminum
- Magnesium
- Nickel Alloys
- Copper Alloys
Types of Metals Not to Use On:
- None
Drawbacks:
Despite the amazing compatibility and efficiency of Argon, it does come with a drawback. As the gas is denser than air, you can only use it on horizontal surfaces.
The gas will go down with gravity, which limits you from using it in overhead or vertical positions.
The issue can be resolved by using higher gas flow, but that will also mean higher consumption of gas, so higher cost. Hence, it will end up becoming an expensive option instead of a cheap one.
Helium
Helium is also a noble inert shielding gas, much similar to argon. However, it has higher thermal conductivity than argon and less density than air.
This gas provides you with deeper penetration and higher welding speed, which means you will get higher quality welds with a much increased depth-to-width ratio.
Helium is ideal for automated or machine TIG welding. The higher speed and deeper penetration allow the machine to craft the perfect welds on the metals.
Also, due to the lower density of the gas than air, it can be easily used for overhead welding. The gas automatically floats upwards.
Helium gas is also ideal for use in DC TIG welding, in which one-side flow of the current achieves perfect ionization to produce a hotter arc and more focused heat. Hence, you will be able to weld thicker materials and achieve deeper penetration.
Types of Metals to Use On:
- Aluminum (DC TIG Weld Only)
- Magnesium (DC TIG Weld Only)
- Copper Alloys
Types of Metals Not to Use On:
- Mild Steel
- Stainless Steel
- Nickel Alloys
Drawbacks:
The cathodic cleaning action does not happen with Helium which comes easily to Argon because the ionization potential of the gas is less efficient in AC welding.
So, it will be difficult to maintain a stable arc with an alternating current. Hence, gas is not a good choice for manual welds and is mostly used in automated welds.
Helium is more expensive than Argon and on a flat surface, you will have to use twice the gas because of its lower density than air, which will increase the cost even more.
Pure Helium has very limited application, but its blends are quite effective in achieving desired welding results.
Hydrogen
While Hydrogen is used in TIG welding, it is never used on its own as a pure shielding gas. Hydrogen is highly flammable and highly reactive, so it should be handled properly.
It is used in small amounts as a blending gas to achieve specific welding needs. Adding hydrogen to the blend allows you to achieve cleaner results and improve the quality of the weld by reducing oxide and nitride contamination.
Hydrogen blends are also used to achieve better weld penetration and faster welding speeds.
Different Hydrogen Blends and Their Uses
Blends of Hydrogen with other gasses are used in various welding applications.
A blend of 5% Hydrogen and 95% Argon, also known as H-5, is used for welding stainless steel and other high-alloy metals. The smaller concentration blend helps clean the weld area and improve its quality without affecting the steel in a bad way.
This blend also improves penetration and welding speed. You can use the blend for austenitic stainless steel and nickel alloys.
Higher concentrations of Hydrogen are also used in some welding applications. Up to 50% Hydrogen blend is used to weld certain types of aluminum alloys.
Types of Metals to Use On:
- Austenitic Stainless Steel
- Nickel Alloys
- Some Types of Aluminum Alloys
Types of Metals Not to Use On:
- Mild Steel
- Aluminum
- Magnesium
- Copper Alloys
Drawbacks
Hydrogen gas is highly reactive and flammable, which limits its application only to a few materials.
You cannot use it for welding copper or copper alloys as it can cause embrittlement and cracking.
You should also avoid using it for various types of steel as it can lead to cracking in the weld area, which is induced by Hydrogen itself.
There are also various safety concerns associated with Hydrogen gas. High heat generation by this gas can cause distortion in the welding pool, which can result in a lack of fusion.
High reactivity also makes it difficult to control and the welding arc is challenging to stable. In addition, high flammability also makes it dangerous as it can form explosive mixtures in the air if not handled properly.
Related: How to Use a TIG Welder?
Other Shielding Gas Blends
Shielding gas blends are very effective for achieving specific welding results. You can use various welds to meet your needs.
While using these blends, it is important to identify and use the right blend for the right type of material. Using a wrong blend will not only result in poor quality weld but can also decrease productivity.
Helium and Argon
One of the commonly used blends is Helium and Argon. You can use the mixture in different ratios, either 75% Helium and 25% Argon or both gasses at 50%.
Using a higher concentration of Helium will provide deeper penetration but might affect the stability of the arc.
On the other hand, if you use a lower concentration of Helium, it will increase the stability of the arc but will decrease the penetration.
Higher Helium concentration also allows you to weld metals that are thicker, even thicker than the manufacturer has mentioned on the welder machine.
The mixture can be used on all metals. So, nothing is exempt.
This particular blend is very useful in cold climates, as it helps compensate for arc heat loss in cold environments.
Argon and Nitrogen
A mixture of 98% Argon and 2% nitrogen is ideal for welding duplex, super-duplex, austenitic stainless steel, and copper.
These materials cannot be welded with the hydrogen blend, so the nitrogen one is used.
However, this blend has very limited application and cannot be used to weld other metals.
Oxygen and Carbon Dioxide Blends
Oxygen and Carbon Dioxide blends can also be used in exceptional cases to achieve desired welding characteristics.
But, you can only use them in smaller quantities as they are severely problematic.
A minute amount i.e. 0.4% oxygen can be mixed with 99.6% helium to solve problems of surface-active oxygen on stainless steel. There are very specific applications, and if you are a beginner, then you have nothing to do with them.
Oxygen and Carbon Dioxide are both reactive gasses that can damage and even destroy the tungsten electrode. So, their application is restricted to very specific conditions in TIG welding.
Frequently Asked Questions
What kind of gas does a TIG welder use?
TIG welder uses various types of gasses for different types of metals and to achieve different types of welding results. Argon and a mixture of Argon-Helium are most widely used as they are compatible with all types of metals.
Does the TIG welder require gas?
Yes, Tungsten Inert Gas welding is incomplete without inert gas that provides the shielding effect while welding. This gas acts as a shield and prevents the weld pool from getting contaminated.
Can you use a TIG welder without gas?
No, you cannot use a TIG welder without gas. The gas is required for both the Tungsten electrode and the weld pool from contamination. Without the gas, the risk is too high and you might cause some serious damage to the machine, material, and yourself.
Can you use the same gas for MIG and TIG?
No, you cannot. MIG welding requires active gas like Carbon Dioxide either as a blend or in pure form, while TIG welding requires the use of pure inert gas. Using Carbon Dioxide in TIG welding can cause erratic sparks which can be dangerous.
Wrapping Up!
To sum it all up, TIG welding requires a shielding gas, which it cannot work without. The choice of gas mainly depends on the type of weld you want and the type of metal you are welding.
In the above post, I have shared all types of gasses you can use in TIG welding with their specific uses, types of metals they can be used on, and their drawbacks. I hope as a beginner, you now know the importance of selecting the right gas in TIG welding.
If you still have any concerns, you can drop them in the comments section below and I will get back to you as soon as I can. Happy Welding!
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