Gas Tungsten Arc Welding Process (Gtaw/Tig); Introduction; Process - Linde BOC RAPTOR Operating Manual

9.0 Gas Tungsten Arc Welding Process
(GTAW/TIG)
Schematic of the TIG welding process
Shielding gas
Arc
TIG filler rod
Weld pool
9.1

Introduction

The Tungsten Inert Gas, or TIG process, uses the
heat generated by an electric arc struck between
a non-consumable tungsten electrode and the
workpiece to fuse metal in the joint area and
produce a molten weld pool. The arc area is
shrouded in an inert or reducing gas shield to
protect the weld pool and the non-consumable
electrode. The process may be operated
autogenously, that is, without filler, or filler may
be added by feeding a consumable wire or rod into
the established weld pool.
24
Collet
Tungsten electrode
Workpiece

9.2 Process

Direct or alternating current power sources
with constant current output characteristics are
normally employed to supply the welding current.
For DC operation the tungsten may be connected to
either output terminal, but is most often connected
to the negative pole. The output characteristics of
the power source can have an effect on the quality
of the welds produced.
Shielding gas is directed into the arc area by the
welding torch and a gas lens within the torch
distributes the shielding gas evenly over the
weld area. In the torch the welding current is
transferred to the tungsten electrode from the
copper conductor. The arc is then initiated by one
of several methods between the tungsten and the
workpiece.