11.0 Troubleshooting and Fault Finding
11.1 TIG/MMA functions
Excessive electrode consumption
Cause
Solution
Inadequate gas flow
Increase gas flow
Inadequate post gas flow
Increase post flow time to 1 sec per 10 amps
Improper size electrode for current required
Use larger electrode
Operating of reverse polarity
User larger electrode or change polarity
Electrode contamination
Remove contaminated portion, then prepare again
Excessive heating inside torch
Replace collet. Try wedge collet or reverse collet
Electrode oxidising during cooling
Increase post flow time before turning off valve
Shield gas incorrect
Change to proper gas (no oxygen or CO
2
)
Erratic Arc
Cause
Solution
Incorrect voltage (arc too long)
Maintain short arc length
Current too low for electrode size
Use smaller electrode or increase current
Electrode contaminated
Remove contaminated portion, then prepare again
Joint too narrow
Open joint groove
Contaminated shield gas. Dark stains on the electrode or
weld bead indicate contamination
The most common cause is moisture or aspirated air in gas stream. Use welding grade gas only.
Find the source of the contamination and eliminate it promptly
Base metal is oxidised, dirty or oily
Use appropriate chemical cleaners, wire brush, or abrasives prior to welding
Inclusion of tungsten or oxides in weld
Cause
Solution
Improper lift arc starting technique
Follow directions as set out on page 43
Poor scratch starting technique
Many codes do not allow scratch starts. Use copper strike plate. Use high frequency arc starter.
Excessive current for tungsten size used
Reduce the current or use larger electrode
Accidental contact of electrode with puddle
Maintain proper arc length
Accidental contact of electrode to filler rod
Maintain a distance between electrode and filler metal
Using excessive electrode extension
Reduce the electrode extension to recommended limits
Inadequate shielding or excessive drafts
Increase gas flow, shield arc from wind, or use gas lens
Wrong gas
Do not use ArO
2
or ArCO
2
GMAW (MIG) gases for TIG welding
Heavy surface oxides not being removed
Wire brush and clean the weld joint prior to welding
Porosity in Weld Deposit
Cause
Solution
Entrapped impurities, hydrogen, air, nitrogen, water
vapour
Do not weld on wet material. Remove condensation from line with adequate gas pre-flow time
Defective gas hose or loose connection
Check hoses and connections for leaks
Filler material is damp (particularly aluminium)
Dry filler metal in oven prior to welding
Filler material is oily or dusty
Replace filler metal
Alloy impurities in the base metal such as sulphur,
phosphorous, lead and zinc
Change to a different alloy composition which is weldable. These impurities can cause a
tendency to crack when hot
Excessive travel speed with rapid freezing of weld trapping
gases before they escape
Lower the travel speed
Contaminated shield gas
Replace the shielding gas
46
BOC Smootharc 180 Multiprocess operating manual
Содержание 180 Multiprocess
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