Welding methods that incorporate Argon as the shielding gas are known as Argon Welding.
As early as 1903, Oscar Kyellberg, founder of the ESAB welding brand, created the prototype of a welding rod to create an envelope of shielding gas around the welding point.
Since the welders usually work at very high temperatures i.e up to 5000 degrees, molten metal tends to oxidize rapidly causing many weld deformities.
During the World World War II-era – These welding machines were re-engineered again and pioneered by ESAB.
However, when the invention was made, Helium was used.
Later, it was discovered that inert gases, such as argon, were cheaper and equally effective.
Nevertheless, helium was relegated to a gas which is mixed with argon when special welding needs were being met.
As of today, there are many inert gases in existence. And thus, the inert gas aka shielding gas is decided based on the process.
The main model of ESAB TIG welder is still named the Heliarc, even though it now mostly uses argon, or argon slightly diluted with helium, as its shielding gas.
Continuing its legacy.
Argon Welding Machine
Any welding machine that uses a separate gas supply for the shielding gas is a candidate for functioning as an argon welding machine.
A MIG welder can potentially be used with 100% argon shielding gas.
However, since MIG welders are used frequently for ferrous metal welding, and are not used to weld aluminum or magnesium, As a replacement CO2 (Carbon dioxide) or a mixture of CO2 and Argon is used.
Pure argon causes erratic arc performance when welding steel.
TIG welding machines, on the other hand, almost always use argon, either in its pure form or combined with helium in small quantities as the shielding gas.
Pure argon is the choice for very thin pieces of metal.
Helium is later added once the pieces reach a certain thickness, and more helium is added as thickness increases.
Sometimes, the argon concentration will sink as low as 25% of the total, depending on the type of material, its thickness, and the depth of weld that is needed.
Helium makes the weld penetration deeper and is also useful for creating a higher welding pool heat with copper and aluminum, which tend to conduct heat away from the joint quickly.
Helium also increases welding speed.
However, excessive Helium is avoided due to the weld quality getting significantly lower. Which can adversely affect the weld joint when subjected to heavy stress or pressure.
Instead of DC( Direct Current), When AC(alternating current) is used with Argon Welding Machines, it results in a weld with excellent quality.
The weld made is of extremely high quality and the appearance of the weld is clean and attractive as well.
Aluminum and magnesium are hence preferred for Welding processes involving Argon Gas.
Nickel and stainless steel are welded with a mix of argon and a whiff of hydrogen.
When the process is done on a weld material made of copper, hydrogen is used in higher concentrations than Argon.
But when strictly working with aluminum, magnesium, or stainless steel, hydrogen is avoided because of the chance of damaging the metal and the weld.
There are namely two types of welding processes, one where you have to push the welding gun towards the weld pool and the other where you have to pull the welding torch/gun towards you.
The processes where you have to pull the welding gun away from the welding pool argon welding gas is used.
This is exactly contrary to the pull welding method used most of the time with carbon dioxide welding.
Argon Welding requires a great deal of precision, being the task that can be used to bond all types of nonferrous metals and is especially useful with alternating current.
Together, these factors make a strong, high-quality weld with a stable arc, and are especially suitable for aluminum and magnesium – two of the most demanding metals to weld in the current scenario.
Dangers of Argon Welding Gas
Argon with an atomic number 18 comes under the category of inert gases, which means they don’t react with the environment under certain conditions.
And thus we can conclude that Argon is harmless as far as safety is concerned.
However, these are supplied in highly compressed tanks, which needs great care. Since the gas is stored pressurized, accidents might happen if the pressure has tampered.
To tackle this issue and increase the efficiency of welding, Argon welding gas regulators were introduced.
They are used to regulate the flow of Argon as a shielding gas. Making sure that the welder gets the gas in the right amount.
Also, Argon is 38% denser than air and might make you feel dizzy if you work for long. It is thus advised to work in a workplace with proper ventilation systems.
If you are welding in the rain, make sure you use the correct amount of argon as due to the storms and wind the gas might flow away resulting in a distorted weld.
Shielding Gas
The inert gas which wreaths your welding pool, blown from the diffuser contained within your welding gun, is almost as vital to the quality of your weld as is the filler material or the method of deposition – and perhaps more so in some circumstances.
Until now, you may have got the point that how crucial the shielding gas is for producing a good weld.
Picking your gas right is one of the things that separates a successful welder from one who does haphazard, slapdash work that may or may not hold solid over the long term.
You will need both experience and further information to make truly viable decisions about shielding gas in all situations.
Choosing a Shielding Gas
I have laid out some rules for you, consider this as a good starting point for choosing your shielding gas:
•Thickness of Aluminum
If you are working with aluminum, the gas is chosen based upon its thickness.
Slabs of Aluminum with ½” thickness or less, including sheet aluminum, are best shielded with pure argon.
Their thicker counterparts should be shielded with a blend of Argon and Helium.
•Working With Stainless Steel
Stainless Steel is a bit more touchy than aluminum and sometimes may require up to three gasses rather than two in most situations.
If you are going for spray welding transfer, you can probably opt for 98% argon, 2% oxygen.
However, it is very common for stainless steel to be welded using a combination of helium, argon, and carbon dioxide, with helium as the major ingredient.
•FCAW-G
FCAW-G, which is a variant of flux-cored wire welding utilizes a particular shielding gas supplied from a tank in addition to the vaporized flux, usually uses either pure carbon dioxide or else a mixture of a quarter carbon dioxide and remaining as argon, the latter requiring a lesser voltage.
Short circuit welding transfer on mild steel uses the same gases as FCAW-G, with differing results for each.
Carbon dioxide, unadulterated with other gases, makes a rough weld but one which penetrates deep into the metal; the carbon dioxide and argon blend produces a shallower weld with a neater, more even surface.
•Using Carbon Dioxide
Spray welding transfer with all types of steel can be made using a gas which is mostly Argon but contains portions of either carbon dioxide or oxygen.
The more carbon dioxide is mixed with the argon, the cooler the arc will be while adding oxygen instead of carbon dioxide will quickly produce a searing hot welding arc.
Choose the mix depending on your application.
For thin, delicate sheets of metal that need a fairly cool weld, 20% carbon dioxide added to 80% argon will furnish good results.
By contrast, if you have two thick blocks of steel and need a deep, strong weld, use 5% oxygen with 95% argon for a truly phlegethontal welding arc.
•Nickel and copper
They are best welded with an argon and hydrogen mixture, with around 5% hydrogen for nickel and 20% hydrogen for copper.
Optionally, some applications with copper welding may need 50% nitrogen and 50% argon, though this is highly situational.
Conclusion
I hope you understood how argon is used in welding and how important it is to use a shielding gas for your welding projects.
Using a shielding gas protects the welds and hence gifts you with a clean looking strong weld which last a long time.