TIG welding is a manual type of welding where the welder has to use both of his hands for a proper weld. Here the welder uses one of his hands to hold the TIG hot torch and the other to add the filler metal to the weld.
Hence, TIG welding is considered one of the most difficult of all the welding processes out there. It is also versatile and professional when compared to welding various metals. This process is done extremely slowly for good quality and precise, small welds.
TIG basically stands for ‘Tungsten Inert Gas’ welding and is also well-known as ‘Gas Tungsten Arc Welding’ (GTAW). This named was coined by the ‘American Welding Society’.
TIG welding was first introduced in the 1940s where Helium gas was the only shielding gas used back then. It was termed ‘Heliarc’ in those days. This has got a registered trademark now that is, “Genuine Heliarc” which is now owned by ESAB equipment.
Tungsten is very hard, slightly radioactive, and is a brittle metal. It is very little used. Here, we convert the tungsten into a non-consumable electrode to do TIG welding.
You can find this element is used in light bulbs, heating elements, and rocket engines. This is radically used in regions where very high temperature is used and you also need to pass electricity continuously.
In TIG welding, as tungsten is the main metal used here, it allows heating temperatures about 11,000-degree Fahrenheit. As told earlier, tungsten has a high melting point and good conductivity which makes welding ease.
The tensile strength of tungsten is 50,000 lbs. per square inch. Being all this tough and rigid, it is brittle though, and can be broken with a heavy tap using a hammer.
How does it work?
You need three basic necessities to fulfill a TIG weld which is heat, shielding gas, and filler metal. The heat in the electrode is formed by passing electricity via the electrode and creating an arc to the metal.
The shielding gas is supplied for protection from a compressed bottle of gas and it flows to the welding area/zone. The filler metal is just a wire that is dipped into the arc and melted by just placing it using one’s hands.
TIG Process Joints
- The tungsten electrode must be moved along the centerline of metal to be welded. The recommended angles for TIG welding square-butt joint are:
- 20-30-degree electrode angle
- 90-degree work angle
- 60-70-degree dray angle
Hold the tungsten electrode about 1/8 inches above the base metal and strike the arc. Once you see the weld puddle formation, add filler to the higher edge of the puddle, and then move the end forward as much as possible.
T-Joints & Lap Joints:
Flat Position Welding:
- Horizontal Position Welding:
TIG welding has the same voltage configuration as Stick welding.
There are two basic types of voltages available which are:
Air-Cooled TIG Torch:
- The air-cooled TIG torch is the cheapest type of TIG welding torch available in the market. It heats a lot during the work and most of the heat the arc produces is wasted.
Water-cooled Tig Torch:
- It is similar to an air-cooled TIG torch but the difference here is that it has a water cooler that has a radiator fitted in it to spray water over it to cool it down.
TIG Welding Stainless Steel
Stainless steel and steel are pretty much similar and hence they have similar welding techniques. It uses the same tungsten electrode and argon gas as shielding gas.
Welding using stainless steel produces more shielding gas coverage. The problem with stainless steel is that if too much heat is applied, then they warp too much or else have the tendency to be not braced properly.
Poor gas coverage:
- When you have improper shielding gas supply or else no shielding gas supplied to the weld for protection, then rapid contamination might occur. This is because too much or too little gas is present around the weld.
- This is a mistake that is mostly made by beginners who have a huge enthusiasm to weld instantly. They use the wrong current flow while beginning the welding process. They even forget whether to use AV or DC current for the metal and the electrode.
- If you weld at abnormally high temperatures, it might lead to the formation of a rough and gritty nature of appearance on the welded portion.
It also weakens the metal. Using the 5356-filler metal is better than the 4043 one as it does not get defective in long usage.
Further, if moisture, grease, oil, and other toxins are not removed from the surface of the weld, then it also leads to contamination.
- Welders must know the right combinations for welding T-joints and fillet joints. The mistakes they make usually with these joints are welding them by:
- The fusion of joints and the weld near the root of the base metal might not occur properly is the welding torch is held too far away, fit-up is not tight, and if the filler rod is not filled properly.
An increase in the arc length is also another factor in this. Transformer-based welding machines also cause this issue as the arc in them keeps on moving between the joint sides.
Lack of Cleanliness:
- When it comes to manual welding, cleaning is the first and foremost process to be done with the welding equipment, metal, and electrodes. This is because a dirty base metal or electrode might cause a lot of imperfections, distortions, cracks, and damage.
- This is one such error made by the welder which cannot be reverted back nor regretted about later on. Overheating stainless steel causes the steel to discolor and look very ugly after the weld is completed. It further reduces the corrosion resistance of the steel.
- Stainless steel available in the market is generally manufactured with a corrosion-resistant coating on top of it and because of this, it is resistant to oxidation. Using shielding gas (argon) to protect the weld can help in preventing any sort of oxidation on the weld as well as the steel.
Sean Coby is a welder par excellence and well respected among the welding community in Woodbridge, VA. He prides himself to be the fabricator and mechanic in the automotive/ diesel industry for the past more than eight years now. As the chief editor of his https://weldinginfocenter.com, he shares his experience to be safe during welding and to take proactive steps for becoming a successful welder like him.