Gas tungsten arc welding (GTAW), also known as
tungsten
inert gas (TIG) welding, is an arc welding process
that uses a non-consumable tungsten electrode to produce the weld. The weld area
is protected from atmospheric contamination by an inert shielding gas (argon or
helium), and a filler metal is normally used, though some welds, known as
autogenous welds, do not require it. A constant-current welding power supply
produces energy which is conducted across the arc through a column of highly
ionized gas and metal vapors known as plasma.
GTAW is most commonly used to weld thin sections of stainless steel and
non-ferrous metals such as aluminum, magnesium, and copper alloys. The process
grants the operator greater control over the weld than competing processes such
as shielded metal arc welding and gas metal arc welding, allowing for stronger,
higher quality welds. However, GTAW is comparatively more complex and difficult
to master, and furthermore, it is significantly slower than most other welding
techniques. A related process, plasma arc welding, uses a slightly different
welding torch to create a more focused welding arc and as a result is often
automated.
Gas metal arc welding (GMAW), sometimes referred to by its subtypes
metal
inert gas (MIG) welding or
metal active gas (MAG) welding, is a
welding process in which an electric arc forms between a consumable wire electrode
and the work piece metal(s), which heats the work piece metal(s), causing them
to melt, and join. Along with the wire electrode, a shielding gas feeds through
the welding gun, which shields the process from contaminants in the air. The
process can be semi-automatic or automatic. A constant voltage, direct current
power source is most commonly used with GMAW, but constant current systems, as
well as alternating current, can be used. There are four primary methods of
metal transfer in GMAW, called globular, short-circuiting, spray, and
pulsed-spray, each of which has distinct properties and corresponding
advantages and limitations.
Originally developed for welding aluminum and other non-ferrous materials,
was soon applied to steels because it provided faster welding time compared to
other welding processes. The cost of inert gas limited its use in steels until
several years later, when the use of semi-inert gases such as carbon dioxide
became common, it became a highly used industrial process. Today, GMAW is the
most common industrial welding process, preferred for its versatility, speed
and the relative ease of adapting the process to robotic automation. Unlike
welding processes that do not employ a shielding gas, such as shielded metal
arc welding, it is rarely used outdoors or in other areas of air volatility. A
related process, flux cored arc welding, often does not use a shielding gas,
but instead employs an electrode wire that is hollow and filled with flux.
(Mail cv to : "apmanpower@gmail.com" )