Thermal Arc 250TS DC CC, Operating Manual

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Description Possible Cause Remedy
12 Arc start is not
smooth.
A Tungsten electrode is too
large for the welding current.
A Select the right size electrode.
Refer to Basic TIG Welding
Guide.
B The wrong electrode is being
used for the welding job
B Select the right electrode
type. Refer to Basic TIG
Welding Guide
C Gas flow rate is too high. C Select the correct rate for the
welding job.
Refer to Basic TIG Welding
Guide.
D Incorrect shielding gas is
being used.
D Select the right shielding gas.
Refer to Basic TIG Welding
Guide.
E Poor work clamp connection
to work piece.
E Improve connection to work
piece.
9.02 Stick Welding Problems
Description Possible Cause Remedy
1 Gas pockets or
voids in weld metal
(Porosity).
A
B
C
Electrodes are damp.
Welding current is too high.
Surface impurities such as
oil, grease, paint, etc. A
B
C
Dry electrodes before use.
Reduce welding current.
Clean joint before welding.
2 Crack occurring in
weld metal soon
after solidification
commences
A
B
C
Rigidity of joint.
Insufficient throat thickness.
Cooling rate is too high.
A
B
C
Redesign to relieve weld joint
of severe stresses or use crack
resistance electrodes.
Travel slightly slower to allow
greater build up in throat.
Preheat plate and cool slowly.
3 A gap is left by
failure of the weld
metal to fill the
root of the weld.
A
B
C
Welding current is too low.
Electrode too large for joint.
Insufficient gap.
A
B
C
Increase welding current
Use smaller diameter
electrode.
Allow wider gap.
D Incorrect sequence. D Use correct build-up sequence.
Figure 8 – Example of insufficient gap or incorrect
sequence