Have you ever wondered what is heliarc welding? well, let’s dive in and give an answer.
What is heliarc welding? Heliarc welding is a welding process that is much more commonly known as Tungsten Inert Gas or TIG welding. You may even hear it referred to as Gas Tungsten Arc Welding.
Heliarc welding is one of many methods that welders use and is considered one of the most challenging to perfect.
It is an ideal weld to use on thin metals such as stainless steel, aluminum, and other non-ferrous metals.
How Heliarc Welding Works
During Heliarc welding, the welder uses an electrical current to create an arc between the base metal and the tungsten electrode.
This will then form a weld pool. It is important that welders do not begin welding until the weld pool looks like a shiny dot if working on aluminum, or a red-hot pool for metals like steel.
When the metal reaches this state, this means that the oxide has been removed from the area, and adding the filler will not pose a contamination threat as you proceed through the welding process.
This process also protects the metal through the use of a gas shield.
Typically, argon gas or helium gas is used (sometimes in combination as the use of helium helps to increase heat) to act as a shielding gas when welding.
Read also: How Does a TIG Welder Work?
This gaseous shield helps to keep oxygen at bay so as not to contaminate the weld.
When helium is used as the gas, then the process is referred to as Heliarc welding.
The Challenges of Heliarc/TIG Welding
For welders, TIG or Heliarc welding is considered one of the most challenging techniques to master.
It requires the welder to multitask and exhibit an exceptional amount of control over multiple factors.
With TIG, the welder has greater control over the electrical current/heat used, sometimes having to use a footswitch or remote switch to control the heat needed to attain the weld pool.
It requires a lot more from welders, as they need to focus on pace, coordination, heat, pressure, and precision due to its complexity.
If you ever tried patting your belly and rubbing your stomach at the same time, you know that multitasking bodily movements require concentration even when the motions are simple.
The same goes for TIG welding. For instance, the welder controls the electrical current with their foot while also using both hands, one with the filler rod and the other with the torch.
As the welder synchronously moves both hands along the work area, he is also gradually dipping the filler into the weld pool at timed intervals for a uniform weld.
Having more control over the welding process also means there are more chances for things to go wrong.
Human error is inevitable, especially during the learning process so if you are a beginner try not to get discouraged if anything goes wrong.
Common Heliarc/TIG Welding Problems
There are many things that can go wrong while welding, so being able to identify the problem will help you quickly assess and remedy the problem.
Some of the most common welding issues are that the:
1. Gas Shield is Inadequate
Sometimes this is due to a loose or damaged consumable fitting, or simply forgetting to turn on the gas shield.
While at other times it may be an inadequate amount of gas being used or even the type of gas/gas blend used.
If the gas shield is not sufficient and oxidation occurs it could result in sugaring of the metal.
2. Wrong Polarity/Balance
Typically, Direct Current Electrode Negative (DCEN) polarity is used during TIG welding, but for aluminum welding, it is better to set the polarity to Alternating Current (AC) which helps rid the aluminum oxide.
Be sure to use the correct setting based on the metal being weld.
3. Grainy Weld
If the bead looks grainy in appearance, this is likely due to the filler rod.
Filler rods have different properties/ingredients from one manufacturer to the next, so always take note of which brands work best for the work you plan on doing.
It could also be that you are using the wrong rod type, so always double-check to make sure you are using the correct rod type for the job and adjust accordingly.
Read also: Different Types of Welding Rods and Their Uses
4. Lack of Root Fusion Integrity
On the initial root pass for T-joints or fillet welds, it is important to ensure the root fusion integrity is not compromised.
This requires patience during the initial root pass, though sometimes fusion integrity can be compromised from an improper fit-up, torch proximity, or improper application of the filler rod.
5. Craters
You may find at the end of your weld that a crater has formed. This is usually a result of dropping the welding power down and removing the filler rod too soon.
Decreasing welding power and the removal of the filler rod should be done at a gradual pace.
If this is a constant problem of yours don’t be dismayed, some welding machines come with a feature to ensure this won’t happen.
Related reading: 11 Common Welding Defects and How To Prevent Them
6. Dirty Base or Filler
To get a quality weld, the most important thing to do is to make sure you are working in a clean workspace and that all the material being used is thoroughly cleaned.
Many metals are made with special coatings to help prevent corrosion, so it is important to clean this off by sanding or grinding the metal to get rid of possible contaminates.
If you want a clean weld, start out with clean material.
7. Stainless Steel Discoloration
Some of the reasons your weld may have discoloration has already been mentioned, but sometimes this is also due to overheating.
Whether it be from lingering too long in one place, the amperage being too high, or if you overheat the metal there is no fixing it.
Starting over is the only option.
Discoloration may also be a result of arc length. The longer the arc the higher the heat and the wider the weld pool.
This will distort the appearance of the weld bead.
Is It Worth it?
Despite the complexity of the process and the challenges it presents, the reward of mastering Heliarc/TIG welding is well worth it.
Welders are better able to control the strength, quality, and details of a weld, and when they become skilled enough at the process, they are more likely to obtain higher-paying job opportunities like aircraft or pipeline welding.
It can become a really lucrative career in the long haul if you really dedicate yourself to perfecting it.
Read also: Pipe Welding Guide: Here´s How To Pass a SMAW 6G Welding Certification
References
https://www.millerwelds.com/resources/article-library/ten-common-tig-problems-a-visual-guide
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