GENERAL MAINTENANCE
GB
(GB) 4
GB
arc welding with coated electrodes. The difference between the two applications
lies rather in the frequency of defects: porosity, for example, is more common in
MIG welding, while inclusion of slag is only encountered in welding with coated
electrodes.
The causes and prevention of faults are also quite different.
The following table illustrates the various faults.
8.0 GENERAL MAINTENANCE
DISCONNECT THE POWER SOURCE FROM THE MAINS BEFORE PERFORMING
ANY MAINTENANCE WORK.
Every 5-6 months, remove accumulated dust from the inside of the welding unit
with a jet of dry compressed air (after removing side panels).
BE EXTREMELY CAREFUL TO AVOID BENDING MOVEMENTS, WHICH
COULD DAMAGE AND CHOKE THE TORCH. NEVER MOVE THE POWER SOURCE
BY PULLING THE TORCH.
PERIODICALLY CHECK the condition of the torch, which is the part most sub-
ject to wear.
8.1
TORCH MAINTENANCE:
1.
GAS NOZZLE:
periodically apply welding spray and clean nozzle interior of
residue.
2.
WIRE GUIDE TUBE:
check the wire passage of the tube for wear. Replace as
necessary.
8.2
CONNECTING THE TORCH
Prior to connecting the torch, make sure that the wire sheath
(18)
is suited to the
diameter of the wire used:
-
BLUE Ø 1.5
for wire Ø 0,6- 0.8 mm.
-
RED Ø 2.0
for wire Ø 1 - 1.2 mm.
(Wire sheath colour for steel wire).
FAULT
APPEARANCE
CAUSE AND REMEDY
UNEVEN LEVEL
- Poor preparation.
- Align edges and hold during spot welding.
EXCESS THICKNESS
- No-load voltage or welding speed too low.
- Incorrect torch inclination.
- Wire diameter too large.
INSUFFICIENT METAL
- Welding speed too high.
- Welding voltage too low for welding application.
OXIDISED BEAD
- Weld in the channel if using a long arc.
- Regulate voltage.
- Wire is bent or over-protruding from the wire guide tube.
- Incorrect wire feed speed.
INSUFFICIENT
PENETRATION
- Incorrect torch inclination.
- Irregular or insufficient distance.
- Wire guide tube worn.
- Wire speed too slow for voltage used or for welding speed.
OVER PENETRATION
- Wire speed too high.
- Incorrect torch inclination.
- Excessive distance.
LACK OF FUSION
- Distance too short.
- Rough out or grind the weld, then repeat.
CHANNELS
- Welding speed too high.
(This fault is easily detected on sight by the welder, and
should be corrected immediately.)
19
21
18
20
22
