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TIG welding is a complicated process that requires many elements, including setting up a shielding gas such as argon to facilitate the weld and protect the welding area. Shielding gases are inert or semi-inert gases that are commonly used in both MIG (metal inert gas) and TIG (tungsten inert gas) welding processes. Argon is a cost-effective and routine gas for manual TIG welders to use for shielding.
So how should someone set up argon for TIG welding? A welder must properly set up argon as a shielding gas in the process of TIG welding by ensuring that the correct gas is supplied in a sufficient tank with an effective argon regulator. This is an important step in the TIG welding process in order to protect the weld material and maintain an efficient flow for arc welding stability.
Since TIG welding, in particular, requires skill, precision, and safety, it’s essential for manual TIG welders to understand how to set up argon as a shielding gas for successful welding. Therefore, a set-up checklist is a helpful tool in addition to understanding the overall process, equipment, and preparation needed for TIG welding. This article provides a checklist and such additional information.
TIG welding is a manual welding process primarily used for critical weld joints or where precise, small welds are required. It’s also used for welding thin sections of metals that are not common steel, such as stainless steel and aluminum, magnesium, or copper alloys. The constant-current welding power supply produces electrical energy that is conducted across the arc through a column of highly ionized gas and metal vapors.
Tungsten inert gas (TIG) welding, also known as gas tungsten arc welding (GTAW), is an arc welding process that uses a tungsten electrode which is non-consumable to produce the weld. The weld area and electrode are protected from oxidation and other contamination by an inert shielding gas such as argon or helium. In addition, a filler metal is also used in most instances.
Tungsten is a hard yet brittle, slightly radioactive metal. Compared to other metals, it has limited uses. However, in TIG welding, tungsten is made into a non-consumable electrode. This electrode is used to create the welding arc.
There are many benefits to TIG welding, including:
- Greater control for the operator over the weld
- Allows for stronger, better, and more precise welds
- Versatility in welding alternate materials
However, there are drawbacks to TIG welding as well, including:
- More complex process than other welds
- Can be difficult for welders to learn and master
- Slower than most other welding techniques
TIG welding requires the welder to use both hands, one to hold the TIG torch that produces the arc and the other to add the filler metal to the weld joint. This unique welding process makes TIG welding difficult to learn, but it’s considered a versatile and high-quality welding method.
How TIG Welding Works
TIG welding requires three elements: heat, shielding, and filler metal.
- The heat is produced by the electricity passing through the tungsten electrode by creating an arc to the metal.
- The shielding is produced from a compressed bottle or tank of gas, generally argon, that flows to the weld area to protect it from the air.
- The filler metal is a wire dipped by hand into the arc for melting.
A welder will turn on gas flow, often located through a valve on the TIG torch. This flow of argon shielding gas protects the weld area from the air. Then, the welder holds the torch over the weld joint close enough that the torch doesn’t touch the metal. The welder presses a foot pedal, and the tungsten electrode on the torch begins an arc.
Once this arc is started, the two pieces of metal to be welded start to melt and create a puddle. The welder then dips a welding wire into the arc to fill the joint and create a single metal piece.
The tungsten metal properties allow an arc to maintain a temperature of up to 11,000 degrees Fahrenheit. Due to its high melting point and good electrical conductivity, the tungsten electrode does not burn.
Equipment Required for TIG Welding
There are several elements of equipment required for TIG welding, and one of the main components is shielding gas, such as argon. This equipment includes: a welding torch, non-consumable tungsten electrode, constant-current welding power supply, and shielding gas source.
TIG welding torches can be automatically or manually operated. They are similar in construction, yet the manual torch features a handle. In addition, the “head angle” can be varied on some manual torches to the preference of the operator.
These metal torches transmit current and heat effectively, and the tungsten electrode is held firmly in the center of the torch. Ports that surround the electrode provide a flow of shielding gas. The torch features heat-resistant and insulating plastics that cover the metal components to protect the welder from heat and electricity.
The TIG electrode is made of tungsten or an alloy due to its highest melting temperature among pure metals. Because of this, the electrode is not consumed during welding, although some burn off or erosion can take place.
TIG welding utilizes a constant current power source so that the current and heat remains relatively constant even if the arc distance or voltage change. This is especially important in manual TIG welding since the operator must hold the torch and maintain arc stability. A constant current power supply prevents heat variations, which can cause welding to become more difficult.
TIG welding power sources feature either lift arc start capabilities or both lift and high frequency arc start capabilities.
Shielding gases are required in TIG welding in order to protect the welding area from gases in the atmosphere, such as nitrogen, hydrogen, and oxygen. These gases can cause fusion defects and embrittle the weld material if they come in contact with the electrode, arc, or welding metal.
The shielding gas, argon in most cases, also transfers heat from the tungsten electrode to the metal and helps start and maintain a stable arc. The composition of a shielding gas depends on several factors, such as the material being welded, joint design, and the intended look of the final weld appearance. However, argon is used in the majority of TIG welding projects.
Use of Argon as Shielding Gas
The primary purpose of shielding gases, such as argon, is to protect the weld area from the oxygen and water vapor within the air. Depending on the welding materials, atmospheric gases can increase welding difficulties and/or reduce welding quality. Choosing an improper shielding gas when welding can lead to porous or weak weld. It can also result in excessive spatters of weld material, which adds to time and labor for clean-up.
Argon is an element (number 18 on the periodic table) that is also considered a noble gas. It is the third most abundant gas available on Earth. Argon is colorless, odorless, non-flammable, non-toxic, and is most commonly used as an inert shielding gas.
For TIG welding, argon is an effective and fairly economical choice as an inert shielding gas, making it the most commonly used shielding gas. Shielding gases are important due to their properties of thermal conductivity and heat transfer, their density in relation to air, and the way in which they undergo ionization.
Argon is heavier than air, so it “blankets” the weld and therefore requires lower flow rates than gases that are lighter than air. Heat transfer is essential when it comes to heating the weld around the arc. In addition, ionization capability influences how easily the arc starts and the voltage required.
Since atmospheric movement, such as any wind or draft, causes the shielding gas to disperse around the weld, TIG welding is generally done indoors in a stable environment so that atmospheric gases can be somewhat prevented from entering the weld area. Shielding gases, such as argon, provide additional protection for the welding area against these atmospheric gases.
Argon also is important when it comes to its role in maintaining arc stability. This results in increased weld penetration, better filler wire transfer, and better weld appearance for the welding project.
How to Prepare a Set-Up for TIG Welding
Though TIG welding produces quality welds and is beneficial for critical welding projects, setting up for TIG welding can be intimidating for those unfamiliar with the process. This set up includes selecting the right tungsten size and type, choosing the proper cup size, and setting up shielding gas and its flow. Here are the basic preparations for a TIG welding set up and required materials:
- Shielding gas: nearly 90% of TIG welding applications can be done with 100% argon as the shielding gas. This includes welding carbon steel, stainless steel, and aluminum. Occasionally, argon and helium are mixed to provide a hotter arc in order to weld alloys of aluminum and copper. These materials have high thermal conductivity, and adding helium results in easier and faster starts for the TIG weld process.
- Type of tungsten: for TIG welding, tungsten is generally alloyed with different elements to achieve certain results or characteristics for a weld. Depending on the project, pure tungsten, thoriated, or ceriated may be used.
- Size of tungsten: the size of tungsten required depends on the application, primarily the thickness of the welding material. Thicker material requires more current and, therefore bigger tungsten.
- Gas flow: TIG welding requires less gas flow for most applications. More flow may be needed for larger cup sizes.
- Polarity: direct current (DC) should be used for welding steel and stainless steel. Alternating current (AC) should be used when welding aluminum and magnesium.
There are many factors to remember and consider when preparing for a TIG weld. However, such attention to detail in setting up for the process will ensure a safe and successful welding project.
How to Set Up Argon for TIG Welding
In order to set up argon as a shielding gas for TIG welding, welders must decide what type of argon gas to purchase, the gas tank size needed, type of argon regulator to be used, and recommended argon pressure.
- Type of argon gas: manual TIG welders should use argon that is 99.99% pure. “Pure” argon refers to the gas being comprised of argon without any other gas mixture present. This is one of the most commonly used welding gases, and major gas supply companies carry it and sell it in various compression tank sizes.
- Tank size: welders want to ensure they have enough shielding gas, so determining the tank size of argon required depends on the potential frequency of use, pressure setting during weld, and pre/post flow settings for the welding project. Welders can check with suppliers as to what they normally stock and what is available when it comes to tank size. An average tank lasts about 3-6 months, depending on use.
- Argon regulator: argon gas tanks, known as argon cylinders, do not generally come with an argon regulator. However, most welders are advised to purchase a proper regulator to ensure successful welds.
- Type of argon regulator: most argon regulators are flow-based in order to regulate continuous flow for the welder. However, some welding systems have built-in argon control systems that require specialized regulators to regulate the pressure of argon flowing into the machine. Welders should consult their suppliers for suggestions regarding types of argon regulators.
- Recommended argon pressure: most welding systems work best at a pressure of 10 psi. This pressure can usually be adjusted depending on the workpiece and the protrusion of the electrode. The further protrusion of the electrode, the more argon pressure is required for proper shielding coverage.
Once the welder has the argon set up properly as the shielding gas and the preparation for TIG welding is complete, the welding process is ready to begin. The following section presents a brief checklist to ensure that everything, including the argon, is set up for TIG welding.
Checklist to Set Up Argon and Other Features for TIG Welding
An overall general checklist is presented here for setting up argon and other equipment for TIG welding. This checklist is to be used once all preparations are made and supplies procured for the TIG welding process.
- Ensure all equipment is prepared, ready, and functioning properly.
- Ensure all safety precautions have been taken in the welding environment and for the protection of the welder.
- Connect the welding torch.
- Connect the argon gas hose and regulator.
- Connect remote control by plugging foot pedal or fingertip control into the machine.
- Connect the work or ground clamp into the machine and fasten the other end to the work piece or table.
- Select polarity by switching amperage setting to AC or DC, depending on welding material.
- Prepare tungsten by grinding to a point with a grinding wheel.
- Assemble the torch for welding and install the tungsten.
- Check the power supply to be sure it matches the machine rating and connect according to the owner’s manual procedure.
Importance of Safety
For the most part, argon is a very safe gas to utilize in TIG welding. It is not poisonous and will not burn. However, since argon is stored in a compressed tank, proper safety protocol is essential to avoid any accidents or injuries. In addition, since most TIG welding is done in confined areas and argon is denser than air, proper ventilation is necessary for the health and well-being of welders using this process.
Manual TIG Welding Applications and Characteristics
TIG welding has many field applications, including assembly and production lines and on-site repairs. Introduced and heavily utilized in the 1940s, the TIG process is known for high quality standards and reliable welds. With this type of welding, there is almost no welding smoke or residue.
Most metals can be welded with TIG procedures, including stainless steel, titanium, magnesium, aluminum, and copper. The process is stable, produces superior quality, and welding defects are generally rare. This absence of defects is due in part to the use of argon as a shielding gas to protect the weld materials and maintain an efficient arc for the welder.
TIG welding equipment does require a higher investment than other types of welding in most cases. In addition, the process can take longer, and the required energy for the weld may be slightly higher. TIG welding can also call for a slightly cleaner environment, so as to reduce the presence and interference of atmospheric gases.
Welding, in any form, is a highly developed skill. Manual TIG welding requires even more skill, precision, and expertise than other methods and processes. However, the results are generally successful and of high quality. It’s important for welders who wish to undertake TIG welding to understand all aspects of the process, including preparing the materials and equipment and setting up the welding torch, electrode, power supply, and the shielding gas—of which argon is the most common and effective.