History:
(Please read history of AC TIG WELDER first) After
success of AC TIG WELDING DC current was tried
and it the DC current cause dirty welds with oxides
entrapped in the welding bead. To counteract this
so called rectifier, manufacturers in USA used
an extremely high voltage with high frequency
spark injector. This system was only partially
effective in cleaning the weld and caused considerable
radio frequency interference. Then Dc current
TIG applied for welding steel instead of aluminum
and it gives good results and commercially supply
of DC TIG starts.
Definition: It is an arc welding process where
in coalescence is produced by heating the job
with an electric arc struck between a tungsten
electrode and the job. A shielding gas (argon
helium, nitrogen, etc.) is used to avoid atmospheric
contamination of molten weld pool. A filler metal
may be added, if required.
Principle: Tungsten is used as electrode; an arc
is generated between job and electrode by DCSP
(Direct current straight polarity) power source,
under coverage of argon as shielding gas. The
arc fuses the job metal and goes ahead to fuse
further metal the molten metal solidifies by reduction
in temperature due to comparative low temp of
air and adjoined metal. |
