Tweco 251 Thermal Arc Fabricator - Manual (Page 61)

FABRICATOR 251
Manual No. 0-4847 5-5 SERVICE
5.04 Welding Problems
FAULT CAUSE REMEDY
1. Welding arc voltage
too high. a. Reduce voltage by reducing the voltage
selection switch position or increase the
wire feed speed.
A. Undercut 2. Incorrect torch
angle a. Adjust angle
3. Excessive heat
input a. Increase the torch travel speed and/or
reduce welding current by reducing the
voltage selection switch position or
reducing the wirefeed speed.
4. Weld speed too fast a. Reduce weld speed.
1. Welding current too
low
a. Increase welding current by increasing
wire feed speed and increasing voltage
selection switch position.
B. Lack of penetration 2. Joint preparation too
narrow or gap too
tight
a. Increase joint angle or gap
3. Shielding gas
incorrect
a. Change to a gas which gives higher
penetration
4. Weld speed too fast a. Reduce weld speed.
C. Lack of fusion
1. Voltage too low a. Increase voltage by increasing voltage
selection switch position.
2. Weld speed too fast a. Reduce weld speed.
1. Voltage too high a. Lower voltage by reducing the voltage
selection switch or increase wirespeed
control.
D. Excessive spatter 2. Voltage too low a. Raise voltage by increasing the voltage
selection switch or reduce wirespeed
control.
3. Weld speed too fast a. Reduce weld speed.
1. Incorrect voltage and
current settings.
Convex, voltage too
low. Concave, voltage
too high.
a. Adjust voltage and current by adjusting
the voltage selection switch and the
wirespeed control.
E. Irregular weld
shape
2. Wire is wandering a. Replace contact tip
3. Incorrect shielding
gas
a. Check shielding gas.
4. Insufficient or
excessive heat input
a. Adjust the wire speed control or the
voltage selection switch.
5. Weld speed too fast a. Reduce weld speed.
Table 5-3a: Welding Problems and Solutions