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Fastening
& Joining Methods
Gas-tungsten
Arc Welding (GTAW) or (TIG)
Tungsten Arc Welding (GTAW) is also referred
to as Tungsten Inert Gas (TIG) Welding.
In GTAW, an electric arc is established
between the work piece and the tungsten
electrode. In contrast to SMAW, this is
a non-consumable electrode process. The
arc is protected by a flow of a shielding
gas, commonly argon (also helium or mixtures
of these two gases), which displace atmospheric
gases from the weld zone. The arc can fuse
two metals together without the use of a
filler metal. A hand-held filler rod can
be placed near the arc and melted to fill
any gaps.
GTAW is commonly used to weld aluminum.
It also is utilized in mild and stainless
steel applications. Ultraviolet (UV) light
from the electric arc is intense and ozone
gas is produced during the process. . GTAW
produces no slag and produces small amounts
of fume. The tungsten electrodes contain
small amounts of thorium (<4%), readily
burning in air to thorium oxide. Thorium
is a radioactive metal and poses an inhalation
and ingestion hazard.
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