Tungsten is a dense substance that stubbornly retains its form at temperatures below 3,400°C. What that means for Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW) is that it’s non-consumable, a feature that facilitates cleaner, more aesthetically attractive weld beads than other welding processes. A weld puddle forms, but there’s no influx of melt material from the electrode.
GTAW
Source: https://en.wikipedia.org/wiki/Gas_tungsten_arc_welding
The result is a stable arc and a consistent flow of energy that allows for super-precise control over the welding process. The non-consumable tungsten electrode also prevents contamination of the weld area, so higher quality, stronger welds are produced on a regular basis. Completing the list of components in a working TIG welding setup, and there aren’t many, there’s an inert shielding gas and the optional inclusion of some kind of filler wire. The shielding gas reinforces the contaminant-less properties of the tungsten electrode by protecting the weld zone from atmospheric oxidization.
Harder to master than other welding techniques, the rewards gained when the challenges associated with Tungsten Inert Gas welding are overcome are many. Precise bead control and intricate weld patterns are only the beginning.
Weave Welding Techniques
TIG Welding Fundamentals: How to TIG Weld
It’s a captivating skill, one that can become quite addictive over time. The process is a little slow, but that’s all the better when developing a TIG welding technique that’s focused entirely on quality. This time around, a Tooliom Dual Voltage TL-200T welding machine has been selected. The handy HF start feature quickens the arc strike at the end of the tungsten electrode. An impressively stable arc slides along a sheet of steel, manipulated carefully by the hand of the welder. Rhythmic motions direct the bead in a straight line. There’s absolutely zero jerkiness and no unevenness to the weld profile.
The correct travel speed has been punched into the front panel of the Tooliom TL-200T. Consistent and steady, the speed is fast enough to prevent heat build-up and distortion but just slow enough to ensure deep weld penetration. The position of the arm and head, also the angle of the welding torch and tungsten electrode, have all been planned out so that there’s no disruption to the movement. The bead flows uninterrupted, cooling into a beautifully applied weld that’s as strong as it is visually pleasing.
MIG/Stick/TIG Multi-Process Welder TL-200M 3 in 1 Welding Machine｜Tooliom
There are other factors in play. An invisible blanket of argon gas is flowing in and around the heat affected zone. It keeps the weld puddle chemically neutral. Inert gas functions as an atmospheric barrier, preventing the oxidizing effects of the air from contaminating the molten puddle. Then there’s the filler wire to introduce into the pool. Again, the tungsten electrode fitted to the welding gun isn’t designed to melt. It won’t melt anyway, not unless the temperature tops 3,400°C, and that’s unlikely. No, filler wires are only added if desired weld pool characteristics are called for in a job. They add strength, bridge material compatibility gaps, and perform as physical gap solutions if the weld zone has problematic dimensions. For that latter issue, the material literally does function primarily as a “filler” material.
Multitasking, as always, is in the mix yet again. There’s maintenance to carry out on the tungsten electrode, shielding gas settings to manage, and several other factors to handle, too, including a high level of manual dexterity while the weld gun is in motion.
Describing A Typical TIG Welding Equipment Setup
There’s the equipment chassis to unpack. Its control panel is overlaid with intuitively configured dials and switches. They set the current and voltage profile of the arc. A number of user-friendly automated settings are accessed through a multiprocessor that’s embedded deep inside the machine. At least that’s the state of affairs in modern TIG welding machinery.
A cylinder of inert gas, probably argon or some blend thereof, is attached by a hose to the machine. A gas regulator and flow rate dial(s) complete this part of the machinery. Moving over to the electrical circuit, a lead exits the welding machine. It terminates at the weld gun, where the tungsten electrode is fitted. It’s here that the arc will be generated. The workpiece is next. It should be prepped, cleaned and otherwise made ready. Finally, for the return circuit, the ground clamp is solidly attached to the metal part. Good electrical conductivity is essential if the arc is to maintain stability. As a worthy mention, there’s no wire feed system to worry about, not with a non-consumable electrode attached. Having said that, the process allows for the inclusion of an optional filler, so feed issues may still occur.
Ready for work, the HF generated arc is struck, the gas hose solenoid opens, and the inert argon envelope is produced. The welder is outfitted correctly, wearing fire retardant Tooliom Mig/Stick welding gloves, a clamshell-designed helmet with an auto-darkening visor, and some coveralls. The Equpment side of things receives a solid checkmark from the welder. The job’s almost ready, except for the preparation phase, that is.
Job Preparation is Essential for Exceptional Results
Perhaps this prep work is what separates pros from keen amateur TIG welders. Before the bright arc illuminates the workspace, the area needs to be prepped. Is the shielding gas cylinder full and fitted with the right blend? It’ll be pure argon or some argon-type blend, possibly with helium. Safety regulations must be observed, making sure of full compliance with all health and safety regulations. That includes the obvious, like welding helmets and gloves, but then there are less obvious measures to introduce. The presence of a fire extinguisher is advised, as is a warning sign that tells other workers to stay away from the area while the work is being done.
The above measure generally applies to all welding jobs, but what about a prep phase that’s expressly designed for TIG welding? Well, the workpiece should be cleaned of oil, grease and dirt, plus any oxidized films. Same for the ground clamp, the arc won’t stabilize properly if the current can’t flow unobstructed. The next tip applies specifically to TIG welding. Because this isn’t a spooled wire, the electrode will incur wear and tear. It’s non-consumable, after all, but that doesn’t mean it doesn’t experience wear due to the super-heated arc. It’ll need to be cleaned and sharpened on a grinding wheel before being inserted into and tightened in the welding gun collet. A quick wipe down with an acetone solution completes the treatment.
None of these steps should be skipped. For instance, scaly deposits accumulate on tungsten electrodes. The arc won’t be steady if it’s filthy. They must be kept clean. It’s the same with general safety and workpiece/equipment prep work; every phase of preparation has its place when endeavoring to develop work habits that will consistently produce attractive, strong weld beads.
Key Factors to Determine Prior to Starting a Welding Project
Alongside the job prep work, the TIG welder focuses on the joint; all of the signs are posted, the safety measures checklist is completed, and the metal in and around the weld zone is spotless. The diameter of the tungsten rod needs consideration, especially since the electrode width and amperage applied are related. If more current is mandated for a project, a wider tungsten electrode will be needed to handle the extra current and dissipate heat. Arc steadiness is also affected by diameter.
Staying with electrode selection, there are a number of tungsten rod “colors” to pick from as well. Those different electrode colors are used as labels. They indicate the presence of different tungsten additives, material supplements that enhance arc related properties. Words like thoriated and ceriated come into play to enhance arc protection and stability, but these are terms that don’t fall under the scope of an article about welding basics. Suffice to say, there are various TIG electrodes to pick from, and there are colors attached to them. These color codes tell welders whether they’re using pure tungsten or some additive-enhanced variant.
Let’s explore three final candidates for pre-work consideration. Starting with the shielding gas, argon is the default atmosphere guard used in TIG/GTAW work. The inert gaseous element provides protection from the oxygen in the air we breathe. The addition of a small amount of helium helps weld pools penetrate deeper. In some cases, hydrogen or nitrogen can be added, but now the welder is venturing into intermediate territory, for such blends are slightly reactive; they can chemically impact weld pools, so care must be taken when selecting such mixes.
That leads us to the alloys TIG welders work on. A few variables are going to impact the work. Take aluminum as a good example of the overall complexity involved. Aluminum can be welded using several techniques, but TIG welding is the better choice when the workpiece is comprised of thin sheets. This is because of the technique’s reputation for being precise and clean. Tungsten Inert Gas welding is also the go-to solution for non-ferrous alloys. Here’s a short-list of the alloys that favor GTAW welding:
- Aluminum
- Copper
- Nickel
- Magnesium
- Titanium
- Stainless steel
- Carbon steel
- Many non-ferrous alloys
A last notable setup parameter needs to be mentioned before a MIG welder can get to work, as described back at the start of this post. Polarity, that’s the final ingredient in this basic ABCs of TIG welding primer. Along with the shielding gas and tungsten electrode type, polarity is the determining factor that decides how well an alloy workpiece will be TIG/GTAW welded. A Direct Current Electrode Negative (DCEN) is almost exclusively. Using this polarity, deeper penetration and a smoother, cleaner bead is easily achieved. Switching to DCEP (Direct Current Electrode Positive), this reverse polarity setting is occasionally utilized in aluminum projects, but a drop in arc stability means this setting isn’t common. Expect to see DC- used almost exclusively in data tables.
The best advice here is to consult data tables on the subject, and there are several of these printed out in the manual for the Tooliom TL-200t to help simplify the question of polarity and electrode selection.
Some Final Remarks on TIG Welding Basics
There are drawbacks, of course, but then that’s something that can be said about any welding process. One or two of them have even been hinted at as this article progressed. The aesthetics we’ve come to expect of TIG welding can at times become production-unfriendly. If speed is the goal, another option might be advised, what with GTAW requiring more time to precisely manipulate its weld bead. There’s also a slightly steeper learning curve to accept, but the rewards make the time spent learning the art of TIG welding entirely worth it in the end.
So, to recap, the process is similar to other arc welding techniques, except for the non-perishable tungsten electrode that replaces consumable wire. That electrode needs to be cleaned and sharpened periodically. On the one hand, then, there’s no birds nest of filler wire to worry about, but there’s still going to be some downtime spent maintaining the electrode, all the same. Otherwise, it’s a versatile technique, one that’s used often on nonferrous metals, yet it’s also popular on ferrous alloys, too, because the process produces such clean and meticulously laid weld beads.
Gaining a solid foundation in all things MIG related, you’ll pick out superior equipment, lay in the relevant current/voltage settings, and know the various colored varieties of tungsten electrodes. An aspiring pro, you’ll soon be TIG welding with the best of them on projects large and small, simple and complex.
Describing Tungsten Electrode Color Coding
|
TIG Polarity |
Electrode Type |
Color |
Benefits |
Special Features |
|
DCEN (Direct Current Electrode Negative) |
Pure Tungsten |
Green |
High arc stability |
None |
|
DCEN (Direct Current Electrode Negative) |
Thoriated Tungsten |
Red |
Abrasion resistant |
Mildly radioactive |
|
DCEN (Direct Current Electrode Negative) |
Ceriated Tungsten |
Gray |
Good arc starting on low current |
Versatile Arc |
|
DCEN (Direct Current Electrode Negative) |
Lanthranated Tungsten |
Gold/Black |
Higher conductivity for increased amperage |
Good for stainless steel |
|
DCEN (Direct Current Electrode Negative) |
Zirconiated Tungsten |
White |
Good for aluminum and magnesium |
Excellent heat resistance |
The ABCs of TIG Welding - FAQ
Q: What is Tungsten Inert Gas (TIG) welding?
A: Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW), is a welding process that uses a non-consumable tungsten electrode to create an arc that melts the base metal and forms a weld. The process uses an inert shielding gas, such as argon, to protect the weld area from atmospheric contamination.
Q: What makes TIG welding different from other welding techniques?
A: TIG welding uses a non-consumable tungsten electrode, which means the electrode itself does not melt. This results in cleaner and more aesthetically attractive weld beads. The process offers precise control over the welding process, produces high-quality, strong welds, and is commonly used for non-ferrous and ferrous alloys.
Q: What are the advantages of TIG welding?
A: TIG welding offers precise bead control, clean weld patterns, and strong welds. It produces welds with minimal spatter and contamination due to the non-consumable electrode. The process is versatile, suitable for a wide range of alloys, and can create high-quality welds on thin materials.