Tungsten inert gas welding, better known as TIG welding, is a shielding gas welding process, which belongs to the group of fusion welding processes. This is an autogenous process in which heat is generated by the arc stroke between the workpiece and the infusible electrode, meaning the electrode is not consumed.
The electrodes are made of tungsten or tungsten alloy. These materials have very high melting temperatures and excellent thermionic emission properties that facilitate arc operation. TIG welding melts the edges of the workpiece. Filling material from toothpicks is used to create the joint.
During the welding process, the welding torch releases inert gas. The gas flow protects the adjacent areas of the electrodes, weld pool, arc, filler material and parts from atmospheric contamination. The gas used is usually argon, which is a mixture of argon and oxygen, and less frequently helium. It is used to obtain the highest welding quality.
TIG welding, with its extensive use of inert gases such as argon, guarantees high purity and precision results on delicate materials such as stainless steel and aluminum. Its ability to work with thin sheets and in critical applications such as aeronautics makes it a preferred option for projects that require the highest welding quality.
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Characteristics of TIG welding
In TIG welding, the current required is provided by a tungsten electrode that is heat resistant and does not melt. From this electrode an electric arc begins that heats and liquefies the material. Surrounding the electrode is a tube exposed to the shielding gas. This protects the hot material from chemical reactions with the surrounding air.
As previously mentioned, noble gases such as argon, helium or a mixture of both are used for this type of welding. Inert and non-reactive gases prevent chemical reactions in the molten bath of hot liquids and substances. In this way, high-quality weld seams are obtained.
Since the tungsten electrode does not melt, the welding material during TIG welding is fed manually or by machine, using an external wire feeder. previously mentioned, noble gases such as argon, helium or a mixture of both are used for this type of welding. Inert and non-reactive gases prevent chemical reactions in the molten bath of hot liquids and substances. In this way, high-quality weld seams are obtained.
Tungsten electrode is the heart of TIG welding, the highest melting point for all pure metals in the periodic table. It is presented by the Tugsene, counting on 3380 ° C, it is for this reason that the electrode is not combined, while the voltage arc is emitted to heat and liquefy the material.
The electrodes are made with a teller process. To improve their properties, they can be mixed with oxide fillers. Depending on the alloy, the electrodes are distinguished by different colors:
Types of tugsene
1. Green tugsene
It is also known as PURE tugsene (WP)
- Smooth hemispherical electrode surface
- DC starting problem
- Low current allowed
2. Turquoise tugsene or rare earth oxides (ws).
It is also known as PURE tugsene (WP)
- Smooth hemispherical electrode surface
- DC starting problem
- Low current allowed
3. Gray tugsene or ceroxide (wc 20)
- It can be used with any material.
- The properties of the primer are very good.
4. Blue tugsene or lanthanum oxide (wl 20)
- Longer life than thorium tungsten electrodes or tungsten ceroxide
- Poor primer properties
Characteristics of TIG welding
TIG welding is used to weld austenitic stainless steels. The techniques are similar to those used to weld carbon steels and low alloy steels, with some differences presented below:
- Cleaning before welding is much more important, due to the greater sensitivity of these steels to the formation of hot cracks in the molten zone.
- The special filters that this type of welding must have, for the outlet of the torch and metal rear cover, reduce the stains of the welding cord, that is, it compresses the stains that arise from surface oxidation.
- Since TIG welding is a smoother welding process, the operator should increase the welding speed as needed when working in different flat positions.
- Wait a moment to remove the soldering iron after soldering to avoid oxidation of the torch tip.
- When cleaning and shaping stainless steel, it must be taken into account that clean and uncontaminated accessories of low alloy steels will be essential.
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As we are seeing, this type of TIG welding has very specific characteristics so that its use is malleable, then we are going to see some advantages and disadvantages of this type of product.
Advantages of TIG welding
As we are seeing, this type of TIG welding has very specific characteristics so that its use is malleable, then we are going to see some advantages and disadvantages of this type of product.
- Solder granules have the highest visual quality.
- Forms welds on all metals, even the toughest welds.
- All welding modes are possible.
- High quality weld seams.
- High productivity.
- TIG welding is suitable for all types of carbon steels, low alloy steels, stainless steels, nickel alloys, aluminum and its alloys, copper and its alloys, titanium, magnesium and other non-ferrous alloys.
- Ideal for welding thin materials.
- There is no spatter as no material is transferred through the arc.
- It is a very strong weld.
- It is highly resistant to corrosion.
- It is a very flexible weld.
- It is widely used in the food and pharmaceutical industries as it is a very clean process that leaves no residue and does not contaminate the base metal.
- It allows penetration control, so it is used for thin and thick root passages, after which the joint can be finished by any other operation.
- It is allowed to obtain welds with the same chemical composition and mechanical properties of the base metal, in the absence of loads.
- Concentrated power delivery, with minimal distortion and heat affected areas.
Disadvantages of TIG welding
- It requires a lot of skills on the part of the welder due to the characteristics of TIG welding.
- It has low welding speed.
- During weld preparation, it is necessary to remove corrosion
- Not suitable for thicker pieces
- This is a difficult welding machine because the tolerances between the electrode, filler rod, and work piece must be tighter.
Do you know how to weld aluminum? We invite you to visit our blog, we explain how to weld on this material using TIG welding
At Perez Precision Works, we excel at providing the highest quality TIG welding equipment, accompanied by exceptional customer service for all your supply needs.
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