Fault Finding - Parweld XTS 203 MMA Operator's Manual

the output current when it detects the rise in arc voltage as the
tungsten is lifted from the work piece.
TIG welding guide ranges
Electrode diameter
0.040" (1.0mm)
1/16" (1.6mm)
3/32" (2.4mm)
Tungsten electrode types
Electrode
type
DC welding of mild steel, stainless
Thoriated steel and copper. Excellent arc
2% starting, long life, high current carrying
capacity.
DC welding of mild steel, stainless
steel, copper, aluminium, their alloys
Ceriated
longer life, more stable arc, easier
2%
starting, wider current range, narrower
more concentrated arc
Guide for selecting filler wire diameter
Filler wire
diameter
1/16" (1.6 mm)
3/32" (2.4 mm)
1/8" (3.2 mm)
3/16" (4.8 mm)
The filler wire diameter specified is a guide only, other diameter
wires may be used according to the welding application
.
Shielding gas selection
Alloy
Aluminium & alloys
Carbon steel
Stainless steel
Nickel alloy
Copper
Titanium
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DC current (amps)
30 – 60
60 – 115
100 – 165
Welding application
DC current range
20 - 90
65 - 115
100 - 165
200-350
Shielding gas
Pure Argon
Pure Argon
Pure Argon
Pure Argon
Pure Argon
Pure Argon

7.0 Fault Finding

MMA welding problem
Description
Gas pockets or voids
in weld metal (porosity)
Colour
code
RED
Crack occurring in
weld metal soon after
solidification.
GREY
A gap is left by failure
of the weld metal to fill
the root of the weld
Possible cause Remedy
(a) Electrodes are damp (a) Dry
electrodes
(b) Welding current is
before use
too high.
(b) Reduce
(c) Surface impurities
welding
such as oil, grease,
current
paint, etc
(c) Clean
joint before
welding
(a) Rigidity of joint. (a) Redesign
to relieve
(b) Insufficient throat
weld joint
thickness.
of severe
(c) Cooling rate is too
stresses or
high.
use crack
resistance
electrodes.
(b) Travel
slightly
slower to
allow greater
build up in
throat.
(c) Preheat
plate and
cool slowly.
(a) Welding current is (a) Increase
too low. welding
current
(b) Electrode too large
for joint. (b) Use
smaller
(c) Insufficient gap
diameter
(d) Incorrect sequence
electrode.
(c) Allow
wider gap
(d) Use
correct build-
up sequence