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Aircraft Maintenance Technology
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TIG Welding
Tips and techniques for better welding|
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By Joe Escobar
Editor
Tungsten inert gas (TIG) welding, also known as gas tungsten arc welding (GTA welding or GTAW), is often used in aircraft applications.
TIG welding provides a clean, strong weld joint that makes it ideal for assembling and repairing various aircraft components. In this article, we will discuss the basic theory of TIG welding and discuss some tips for better TIG welding results.
Basic Theory
In TIG welding, a non-consumable tungsten electrode is used to establish an arc on the base metal. The heat of the arc produced melts the base metal and produces a weld pool. In contrast to normal stick welding, when TIG welding, an inert gas shields the weld area in order to prevent air from contaminating the weld. This shielding gas prevents oxidation of the tungsten electrode, the molten weld puddle, and the heat-affected zone adjacent to the weld bead.
In a typical TIG setup, an AC/DC welding machine is used with a flow of shielding gas. The shielding gas goes through a regulator and flow meter and on to the torch. The torch has a collet/collet body combination that holds the electrode. A heat-resistant cup or ceramic nozzle surrounds the electrode and controls the gas shield. In addition, water-cooled TIG machines are available for high-amperage welding applications.
Personal Protective Equipment
Although TIG welding does not produce all of the metal spatter that is associated with stick welding, it still generates intense heat and light. In fact, the clearer atmosphere around the TIG arc can cause up to twice the amount of infrared and UV rays compared to normal arc welding.
Any exposed skin will be burned similar to an extreme sunburn. Welders should wear personal protective equipment such as a welding helmet, welder’s protective gloves, and clothing. Of course, fire-resistant cloth and leather clothing and accessories are recommended. A word of caution — cotton should not be used as it does not provide sufficient protection and it deteriorates quickly under the infrared and UV rays produced by the TIG welding process. As a tip, dark clothing should be used to reduce reflection of light behind the helmet.
Other Safety Precautions
The following general precautions should be observed to protect you and co-workers from the hazards associated with TIG welding:
