A career in welding is surprisingly rewarding financially. In a report by the Wall Street Journal in 2015, a welder can earn as much as $140k per year. Energy and construction-related industries are demanding for more skilled welders until the year 2022 – and that’s only in the US. Global demand for skilled welders is seen to rise as well.
With this fact, individuals interested in welding should prepare themselves with the basics of learning about or using this skill. One of the most difficult and important types of welding that one must understand is called TIG welding.
While learning, one must know the right kind of equipment and materials to be used. For example, it’s easy to look for the right tungsten grinding wheel. Finding the right tungsten carbide grinding wheel, however, is a bit challenging. These two are some of the important details one has to know about TIG welding.
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What is TIG Welding?
TIG (tungsten inert gas) welding, officially recognized by the American Welding Society (AWS) as gas tungsten arc welding (GTAW), is a manual welding process that uses tungsten to heat and melt metals. For this reason, TIG welding requires a few equipment and several materials in order to work properly.
Aside from tungsten, TIG welding requires tungsten grinding wheel, electrode, TIG power supply, TIG torch, and shielding gas. Knowing each of these materials can reveal more about the process of welding.
Electrodes made of non-consumable tungsten are used to weld together different kind of metals in TIG welding. It is an important part of the welding process because it acts as a conductor for the current required to create an electric arc. The arc is the discharge of electricity in order to heat and melt metals during welding.
There are different kinds of electrodes used in TIG welding, although all of them are made of tungsten. Each one requires one or more different kinds of electric current when used. Lanthanated gold, ceriated grey, and thoriated red tungsten electrodes need direct current (DC) electricity. On the other hand, Lanthanated blue and rare earth mix purple tungsten electrodes need alternating current (AC) electricity. Only the pure tungsten green uses AC.
While tungsten electrodes are used to weld a variety of metals, it has to be shaped or sharpened first with a grinding wheel for tungsten.
Sharpening tungsten electrodes
To sharpen electrodes, a grinding machine (a bench grinder would do), a hand drill, and a tungsten grinder wheel will be needed. An electrode is to be securely inserted into a hand drill the same way one would do with a drill bit. After that, carefully grind the electrode on the grinding wheel. After grinding, the electrode can be cleaned with a dedicated belt sander.
Electrodes are shaped into two types: pointed and rounded. Pointed electrodes are used to weld ferrous metals. Ferrous metals contain iron in them and examples are stainless steel, carbon steel, mild steel, wrought iron, and cast iron. They are durable and have a high level of tensile strength (resistant to breaking even under tension).
On the opposite, rounded electrodes are used to weld non-ferrous metals which contain no iron in them. Examples are aluminum, copper, lead, zinc, and tin. Non-ferrous metals are highly resistant to corrosion and rust. Precious metals such as gold and silver are also non-ferrous.
On the other hand, it is important to note that welders should use a dedicated TIG tungsten grinding wheel. A grinding wheel used for steel and other metals can leave contaminants in the tungsten.
Which grinding wheel to use
Choosing the right grinding wheel is easy. Most welders choose between a diamond wheel and a tungsten electrode grinding wheel made of carbide, also known as the green wheel (because of the raw material color). However, others opt for aluminum oxide wheels.
Diamond wheels are the most recommended ones for grinding electrodes. They produce clean, precise shapes. They are also highly durable. However, many find them expensive. It’s fair enough to use tungsten carbide wheels instead. On the other hand, aluminum oxide wheels are used for general purpose.
Shielding gasses used in TIG Welding
There are three types of gasses used in TIG welding. Each gas is used for welding different types of metal.
The most commonly used shield gas is argon because it is easily found in the Earth’s atmosphere. It is used for welding titanium, aluminum, stainless steel and other types of steels.
Some welders add 2-5% of hydrogen with argon. It’s been said to produce welds that look cleaner and without surface oxidation or rust. To achieve this, the combination of argon and hydrogen enables the electric arc to become hotter. As this happens, welding speed increases. However, hydrogen does not work well with carbon steels and aluminum alloys.
The third type of shielding gas used in welding is helium. It is also sometimes combined with argon. It also makes the arc hotter and thus, produces speedy welding. It also enables filler metal to penetrate deeply into the welded material. However, helium is expensive and it’s not easy to start the arc if this gas is used.
On a side note, when welding was introduced in the 1940s, helium was initially used. That is why some old people today refer to TIG welding as Heliarc welding.
Where is TIG Welding used?
TIG is commonly used and preferred by many because of its high-quality, precise welds. Because of this, it is used in many industrial sectors. However, it requires a higher level of mastery compared to other types of welding. This is because a welder has to use two hands when using TIG welding. In other words, TIG welders should be well-trained.
Aside from producing precise, high-quality welds, TIG welding has many advantages over other types of welding.
TIG welding works on almost all metal types with high melting points. It is popularly used for welding nickel-based alloys and aluminum stainless steels. It is also used for joining magnesium and aluminum. It is also good for welding reactive metals such as zirconium and titanium. These reactive metals work poorly with nitrogen and oxygen. At the same time, they become brittle when exposed to air.
TIG welding is also perfect for joining metals with a thin base. It also produces less smoke and fumes, so visibility is high while working. It requires minimal finishing; although the use of tungsten grinding wheel when sharpening electrodes requires cleaning after. What’s more, there are some instances when filler metal is not required. This usually happens when TIG welding is used to fuse two metals together.
The next step
There is no better teacher than experience. Purchase the materials needed and try out TIG welding with a well-trained welder to see how it works up close.