Argon welding is very popular among both industrial and domestic welders.
In this article, you’ll learn everything you need to know about Argon welding for both tungsten inert gas welding (TIG) and metal inert gas welding (MIG) welding process for your welding projects.
Argon, atomic number 18, is an abundant noble gas that has various applications in different industries. Its stable electron structure allows it to remain unreactive under a variety of conditions.
What Are The Uses Of Argon In Welding Applications?
Argon is an inert noble gas, which means that it will not react under any circumstances. In welding applications, high temperatures usually reach extreme to values (as high as 5000°) which can cause unwanted chemical reactions.
Argon, however, remains perfectly stable at those elevated temperatures and continues to function properly.
Primarily, Argon and its mixtures are used for two processes in TIG welding welding metals such as stainless steel or mild steel, as a shielding, and purging.
Both processes are a bit different but their end-goal is to create an inert environment for the weld metal during the welding operation.
In the shielding process, the welded area is flushed with shielding gas to maintain the integrity of the welded material.
Heat acts as a catalyst for many chemical reactions and Oxygen, Nitrogen, and Hydrogen in the air can bond with the welded joint to introduce porosity in the region.
Welders use shielding gases to create an inert barrier around the weld pool. The barrier prevents any other contaminants from entering and protects the metal.
Shielding gases are a crucial part of any arc welding process.
Argon is not the only shielding gas used in the industry, but it is certainly the most widely used option due to its properties. Despite its excellent properties, Argon welding gas is quite affordable due to its abundance.
Argon Purging
Another common welding process with stainless steel pipe welding is argon purging.
The process is based on shielding and extends the inert barrier to cover the other side of the welded joint as well. It is required for many welding standards.
This gives the welded joint an aesthetic look and enhances the overall protection from oxidation.
Generally, the purging process is commonly used when TIG welding Stainless Steel and pure Argon is arguably the most preferred welding gas for this process.
This is used in food or chemical pipework to prevent impurities or bacteria on the inside weld bead of the butt weld.
With the molten pool protected from the inside as well, the chrome will not oxidize preventing any sugaring of the internal weld bead.
The Benefits Of Using Argon For Welding
Argon stands at the helm of all the shielding agents out there. It has an excellent penetrating ability and can maintain a stable arc to facilitate the weld.
By providing a higher level of control of weld puddle, it can be used in gas tungsten arc welding to weld sheet metal.
Many welders favor Argon welding gas as it is very economical when compared with other alternatives available in the market, giving them the ability to produce the desired cosmetic welds on thin sheet metal for an affordable price.
Some of the benefits of using Argon, either pure or in mixtures, for both MIG and TIG applications, are listed below.
Argon Is Both Inert And Abundant
Argon belongs to the group of inert gases, but unlike the other gases of this group, obtaining Argon is very simple.
This gas is considered the third most common gas in the Earth’s atmosphere and can be extracted by liquifying Air.
The process may sound tricky, but it’s simpler than the processes to obtain other gases like Helium.
Due to its noble characteristics, Argon is neither toxic nor flammable. This makes it a relatively safe option for welding operations.
There are, however, other safety concerns related to Argon welding which will be discussed later.
Argon Creates A Stable Arc
Being a stable gas, Argon has no ionizing potential, which means that the current used for arc welding would have a constricted path.
This allows Argon to create a stable welding arc that is more concentrated and improves penetration. Another quality of Argon is its low thermal conductivity.
This welding gas gives a lower heat transfer rate outside the high temperature of the weld pool and keeps the heat concentrated, which further enhances the stability of the welding arc.
The lower heat conductivity of Argon welding gas is also the main reason why this gas is pretty much the only great option for you if you want to weld Aluminum or other non-ferrous materials.
Argon Delivers Cleaner And Stronger Welds
As a result of its stable arc, the results of Argon welding gas delivers are both functional and aesthetic.
The shielding effect of Argon protects the welded puddle from weaknesses by maintaining the structural integrity of the material.
Similarly, Argon prevents your welded joints from looking unappealing by resisting carbide formation, excessive spatter, discoloration, and several other visual defects.
Argon Can Make Various Blends With Reactive And Non-Reactive Gases
Since pure argon is non-reactive, it can be easily mixed with any other shielding gas without having a chemical reaction with the metal surface or the filler wire.
This quality allows welders to make several blends that perform according to their specific needs.
MIG welding is a blend of helium and argon gases which are both inert.
MAG welding is where the introduction of reactive gases such as carbon dioxide (CO2) or oxygen plays an important role to provide a faster travel speed and higher metal deposition rates from the higher arc temperatures.
The welder has the ability to increase filler metal speed while still having a stable arc that minimizes puddle control and reduced spatter.
The reactive gases for example, in many TIG applications dealing with thicker pieces of non-ferrous metals, pure Argon can’t deliver quality results.
In such cases, a mixture containing Argon and Helium would be a better choice as it would retain the positive attributes of both noble gases.
Interested in learning more about welding gas mixtures? Check out the qualities of the most popular welding mixtures in the market today.
MAG welding With Argon ( Active Gas Welding)
For the shielded metal arc welding process, an argon mixture is more commonly used in the form of blends to improve the metal transfer on the thicker materials, while providing a lower weld bead profile due to the deeper penetration.
To read a dedicated article on the effects of adding carbon dioxide, helium, or oxygen to the welding shielding gas click here.
If you are dealing with non-ferrous metals, in the case of MIG, Argon welding gas can be mixed with some reactive gases like CO2, Nitrogen, Oxygen, and even Hydrogen.
While you can also use pure Argon as a shielding gas for MIG welding, the resulting weld will be narrow and unattractive.
TIG Welding With Argon
For TIG welding, (Gas Tungsten Arc Welding) Argon is a ‘one size fits all’ solution that can deliver acceptable results under almost all circumstances.
Argon can be used in both AC ( Alternating current) or DC (direct current). In its pure form, the shielding gas gives you excellent welds that look incredible and have strong mechanical characteristics.
Argon is also a commonly used gas for the process of purging, which is very common for TIG welding Stainless Steel and other corrosion-resistant metals.
The welder will usually have the welding machine at post flow settings at around 5-7 seconds.
The welder will leave the cup over the completed weld bead to prevent surface oxidization as the weld cools.
This will also protect the tungsten (pointed electrode) by continuing the flow of argon after the weld.
For some applications with non-ferrous metals and very thick pieces, welders use mixtures of an Argon/Helium gas blend for increased weld penetration, speed, and arc stability.
Similar to Argon, Helium is also a noble gas. It is either purchased in a mix in a compressed tank or it can be mixed by the welder with a Y piece.
However, you must remember that TIG welding can’t be performed with reactive shielding gas.
The mixtures of shielding gases used in MIG/MAG welding that contain CO2, Oxygen, and other reactive gases will fail in TIG welding as they’ll start to react with the base metal, tungsten electrode and contaminate the weld pool, degrading the base metal and the introduced filler metal.
Some Common Argon Shielding Gas Mixtures For Welding Applications
While Argon is extremely useful in both TIG and MIG welding application, there are many instances where using it alone would not be suitable.
Stick welding for one. In such cases, welders use different mixtures to improve a specific quality such as the welding speed, penetration, etc.
In almost all welding blends, the Argon mixture is featured in a very significant percentage, as it is by far the most suitable gas for welding applications.
For a given arc length, the addition of helium mixtures to pure argon will increase the arc voltage by 2 or 3 volts. (open.edu)
In the following sections, we have compiled a list of the four most commonly used blends in the industry.
You’ll notice that the percentage of Argon in all these cases is quite high when compared to the other gas.
As described before, gas blends for TIG can work with MIG welding as well, but the opposite is not true. MIG welding gases can’t be used for TIG applications.
90/10 Argon-Helium (TIG)
This blend inert shielding gas has 90% Argon and 10% Helium. The higher heat input from the helium addition gives it incredible fluidity to the weld puddle and increased arc stability.
Using this would give you an incredible finish and allow you to increase your welding speeds.
The added helium provides a deeper weld penetration and a flatter bead profile and being able to TIG weld at high speeds.
75/25 Argon-Helium (TIG)
The blend of 75% Argon is the best choice for applications involving thicker weld joints of non-ferrous materials like Aluminum.
Aluminum has a high thermal conductivity so the machine needs to provide a lot of amperages to overcome the cleaning action of the alternating current.
If you require deeper penetration, or the material thickness is past your machines amperage limit using pure argon, you can use the 75/25 argon/helium blend instead.
It gives you fast welding speeds and reduces both oxides and heat-affected zone in the resulting weld while retaining the deep penetration profile.
This gas is commonly used to make aluminum boats, industrial heat exchangers, pipes, and other intensive industrial applications. Very rarely will pure helium be used as primary shielding gas due to its high cost.
75/25 Argon-Carbon Dioxide (MIG)
The mixture of 75% Argon and 25% CO2, better known as C25 is perhaps the most commonly used blend for MIG welding in the industry.
This blend with its higher levels of carbon dioxide gives the overall best performance when it comes to finished weld appearance, arc stability, and broader penetration shape.
CO2 is well known for broader penetration and the addition of argon is able to reduce the excessive spatter of pure CO2.
Other important factors are the higher welding speeds. Whether you are a home hobby welder or are working professionally, C25 is a perfect choice to cover most of your MIG welding needs on carbon steel.
It is well suited for short circuit MIG/MAG all the way up to globular transfer.,
A85/15 Argon-Carbon Dioxide(MIG)
This is another popular MIG welding blend that can handle many welding jobs at a decent speed and finish.
However, the penetration ability of this shielding gas is quite limited, which makes it suitable for dealing with base material thicknesses ranging from 1mm to 12mm.
The Best Gas Tank Size For Argon Welding
Argon is a commonly used gas for welding operations where back purging is required and need a higher flow rate.
You can’t be stuck with a very small cylinder and keep on wasting your time on frequent trips to the refilling station, or you may lose your purge on a critical weld.
Similarly, it’s also impractical to have the biggest cylinder if you need a portable option.
To determine the most appropriate gas tank size for your applications, you must consider your applications and other requirements before making a decision.
You can refer to the table to learn more about the common sizes Here.
How Long Does An Argon Welding Tank Last?
The total operational time of your welding gas tank depends on two factors. The total volume of the cylinder and the gas flow rate you’ve set.
The flow rate is an important parameter for both MIG and TIG welding applications because it determines the protection level of your joint.
You’ll need to have a perfect balance if you want high-quality weld as both low and high flow rates can affect your weld quality.
Most welders keep the gas flow rates between 20-35 cfh for MIG and 15-40 cfh for TIG welding.
Multiple factors affect the required flow rate for your welding applications, which can be outside the given ranges.
To calculate the overall welding time, use the following formula:
Welding time (hours) = Gas bottle volume in cubic feet (cf) / flow rate in in cfh
To understand this, let’s take an example of a 125cf gas bottle with a discharge flow rate of 20cfh.
125cf / 20cfh =6.25hrs
This will give you an approximate welding time of 6.25 hours. You can find how long your welding tank will last by using the above formula for your gas cylinder.
Important Safety Considerations When Welding With Argon
Argon is non-toxic, non-flammable, non-reactive gas. But there are some very serious dangers.
Because argon is stored under extremely high pressure in a compressed tank, proper safety procedures, and bottle storage are paramount.
When storing the gas, have the bottles secured to prevent them from falling over and breaking the valve off.
There have been many cases of the bottle turning into a high powered rocket that can go through a concrete wall from the high-pressure gas escaping so violently.
The high-pressure gauge needs to be in excellent working order to correctly regulate the flow of gas.
Leaking or damaged gauges can introduce impurities into the shielding gas or the gas leak can build up in the work area to high levels, depleting the oxygen and reducing the air quality.
When purge welding stainless steel or titanium pipe, almost twice the amount of argon is used.
If the welder is welding in a confined space, the argon builds up to a limit where the oxygen levels are so low the person drowns in the argon. Many deaths are recorded each year from inert gas asphyxiation.
If the rate of oxygen in the environment falls below 6% the person will stop breathing followed by convulsions and cardiac arrest.
This can happen almost immediately at this concentration. People have died trying to rescue a workmate in an asphyxiation event and died themselves.
Argon is heavier than air so it builds up as if it is water filling the environment.
Anyone going into a tank or a confined space needs to have a safety watch, oxygen detector, and an escape plan in case of an emergency.
Closing Thoughts For Welding With Argon
Argon is a high purity shielding gas among the most common inert gas used in any welding process.
Its versatility, functionality, and affordability have catapulted its popularity among professional welders and the hobby welders.
Both pure Argon and its blends are regularly used by MIG and TIG welders worldwide.
In this article, we addressed the most basic information about Argon welding gas everyone associated with the industry should know.
Interested in learning more about welding, common equipment, and other components?
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