TIG WELDING
TIG (Tungsten Inert Gas) welding or Gas Tungsten Arc Welding (GTAW) is an arc welding process that uses an arc between a tungsten electrode (non – consumable) and weld pool. The process is used with shielded gas and without application of pressure. The process may be used with or without addition of filler metal. GTAW or TIG has become indispensable as a tool for many industries because of high quality weld produced and low equipment cost. TIG (GTAW) advantages: • TIG produces superior quality welds, generally free of defects. • TIG is free of sputter which occurs with other arc welding process • TIG can be used with or without filler metals as required for specific applications • TIG allows excellent control of root pass weld penetration • TIG can produce inexpensive autogenous welds at high speeds • TIG can use relatively inexpensive power supplies • TIG allows precise control of the welding variables • TIG can be used to weld almost all metals, including dissimilar metal joints. • TIG allows the heat source and filler metals additions to be controlled independently. TIG (GTAW) limitations: • TIG has deposition rates that lower than the rates possible with consumable electrode arc welding process. • TIG require slightly more dexterity and welder coordination than with gas metal arc welding or shielded metal arc welding for manual welding. • TIG is less economical than the consumable electrode arc welding process for thicker section greater than 10 mm (3/8 in.) • There is a difficulty in shielding the weld zone properly in drafty environments Potential problems with TIG process include: • Tungsten inclusions can occur if the electrode is allowed to contact the weld pool. • Contamination of the weld pool can occur of proper shelding of of the weld metal by the gas stream is not maintained. • There is low tolerance for contaminations on filler or base metals • Possible contamination or porosity is caused by coolant leakage from water-cooled torches. • Arc blow or arc deflection, as with other processes