The method of turning a metal into liquid in order to be joined with the use of inert gases and tungsten electrodes, by passing high-frequency current is known as Heliarc Welding.
The earliest existence of the Heliarc Welding can be traced back to 1890, when this process was first started by C.L. Coffin. Originally known as ‘electrode welding’, the heat was produced using a carbon arc. Until the year 1941, the process came to the form it is used today, and the name given to it was “Heliarc Welding”.
In this article, we have tried to explain everything about Heliarc/TIG Welding methods and processes. We have discussed the equipment, methods, advantages and disadvantages associated with it.
What Do You Mean By Heliarc Welding?
Heliarc Welding is a method that uses any one inert gas and tungsten electrodes. A high-frequency current is passed through the machine to heat and melt the metal to convert it into its liquid form for it to be joined later. The electrodes are used to sustain the electrical arc created between the metals.
This technique is quite similar to the gas welding technique which involves the melting of a metal at the junction at which the pieces meet. Heliarc Welding does not make use of a filler material like in Gas Welding which uses materials like electrode wire or a carbon rod as the material source.
What Is The Equipment Involved In Heliarc Welding?
There are several kinds of equipment that are needed in the Heliarc Welding method, including a power supply for providing the electrical current required to form an arc. Some of the other things involved in completing the process comprise filler rods, shield gas, and tungsten electrode.
One of the eminent tools required to get the job done is the torch. Some workers use consumable tungsten electrodes that are known to wear down as they pass through the machine while some others use non-consumable electrodes.
There are various kinds of weld associated with the technique, like lap joints, butt and fillet. The size of the product is restricted by the ability of the machine to produce heat.
Why Is Heliarc Welding Important?
You will frequently find TIG or Heliarc welding being used for industrial purposes in case of large-scale projects like ships and cars. The technique can also be implied when repairing a home or a car, however with several jobs, the technique requires a special machine which requires a huge amount of power. Therefore, it is difficult to achieve it in the home setting.
TIG or Tungsten Inert Gas Welding strengthens the metals by creating an effective bond between them. This process is also used to eliminate the impurities through this technique. This method is difficult and complicated to learn that the other welding methods like the MIG as it needs extra precision and dexterity when gas is used to protect the metals from exposure to oxygen.
What Are The Advantages Of Heliarc Welding?
In this section, we will discuss the positive aspects of Heliarc Welding.
1. Strong Welds
With the use of the Heliarc Welding method, the produced metals are stronger than the products obtained in other methods of welding as this technique creates a stronger metal bond. The requirement of less energy for the method makes the technique efficient in the broader aspect.
2. Versatility
The huge advantage of the TIG or Heliarc Welding method is that the method is applicable for several kinds of materials, which includes nickel alloys, titanium alloys, aluminium , magnesium, chrome, stainless steel, and even exotic metals.
3. Quality Work
The method of Heliarc Welding is very accurate as it can be achieved with a great degree of precision. This enables it to be utilised to make structures stronger and critical parts of the construction.
What Are The Major Disadvantages Of Heliarc Welding?
There are two major disadvantages of the Heliarc Welding Method. They are discussed in detail below.
1. Time To Learn
TIG welding requires a great degree of dexterity and skill, which makes it difficult to learn in comparison to the other methods of welding. This technique also needs a great understanding of time, angles and electricity.
If you try this technique without proper training, the process might result in an uneven joint or errors in the alignment which can hamper the strength of the final outcome.
2. Multitasking
This method will teach you to multitask like no other. As you need to constantly keep an eye on maintaining the arc, you cannot focus on just one time at any particular time. The technique also requires you to watch the machine and the gears, while keeping a check on the timings before moving from a particular position or focusing on something else.
What Are Some Of The Regular Problems Experienced By TIG/ Heliarc Welders?
When we are talking about Heliarc Welding technique, things are very complicated to master and some of the things can easily go wrong. If one is fully not aware of the technique, you can have a faulty end result at hand or you can get injuries owing to an electric shock. Some of the regular mistakes while using this technique are discussed below.
1. Usage Of Too Less or Too Much Metal
In order to produce a quality weld, you need to use the right amount of filler metal during the process of welding. The use of too little or too much filler metal can have adverse effects on the appearance and strength of the weld.
In case of lesser filler metal, the weld produced will not be as strong as it should be. Also, it might not be durable enough to endure the regular wear and tear which can lead to a future failure.
In case of more filler metal, the weld can be uneven and/or bulky. This can result in weak areas in the weld which can result in a future failure. Also, the use of excess filler metal can decelerate the process of welding which makes it difficult to handle the workpiece.
2. Incorrect Polarity
There can be times when the poles on the Heliarc welder are placed on the wrong ends. This will allow the electricity to flow in the opposite or wrong direction and the result will not be welded well, this will lead to an injury if not careful and certainly a bad weld.
In several cases, direct current electrode negative or DCEN is used, but while welding magnesium or aluminium, alternating current or AC electrode positive must be used.
3. Improper Pulsing
In case of a Heliarc welder the time of pulsing is very important. This is due to the fact that it can be problematic for the filler metal and the arc. For instance, if the pulsing is slower than required, then the weld can end up cracking while if the pulsing is faster than required, the weld might end up with porosity.
4. Usage Of Incorrect Gas or Shielding Gas
It is basic that you must use the right kind of gas as it can have an impact on the weld and the strength of it. For instance, a gas too lean can end the final weld with porosity while a gas too rich can give a final weld with excess splatter.
5. Wrong Travel Speed
Some Heliarc welders enable the user to set the required travel speed for the process of welding so that you can control the speed or quality. If the travel speed is either too slow or too fast, it can have a negative impact on the weld accuracy and the overall strength of it.
Several times, the wrong travel speed can lead to erratic arc behaviour and bad puddle control that leads to porosity in the final weld.
6. Usage Of The Worn Tungsten Electrode
When trying to achieve quality welds, the use of a worn electrode can cause problems which is a common error in case of Heliarc welding. The results of a worn tungsten electrode will cause a huge ball on one end, which can restrict the transfer of heat and an erratic arc. This will cause cooling at the end of the weld and therefore causing poor penetration.
In case the tungsten electrode leans on a particular side, it can lead to a concave weld puddle.
Final Word
Through this article, we have tried to mention all that you need to know about Heliarc welding. TIG/ Heliarc welding is the building blocks of the world that we see today. Without the use of Heliarc welding, the production of planes or large-scale ships would not have been possible.
It is quite difficult to overstate the importance of Heliarc welding and how the increased use of stainless steel and aluminium came into existence due to the possibility of clean, strong welds achieved through the Heliarc welding process. If you still have any kinds of questions regarding the topic or suggestions about the article, do write to us in the comments section below.
