202C Flashcards
GTAW (33 cards)
when installing electrical power welding machines, the installation must comply with:
A workplace health and safety regulations.
B applicable local electrical codes
C American welding society regulation
D welding shop installation procedures
Badly discoloured cable lugs indicate that the connection has:
A. overhead during use.
B. been heated during use
C. been exposed to corrosive atmosphere
D. lost its protective coating
continuous high frequency current maybe required with GTAW when:
A. thoriated tungsten electrodes are used.
B. the electrode is ground to a sharp point
C. it is necessary to increase penetration
D. you are using alternating current
What current type produces good penetration and oxide removal when using GTAW on aluminum
A DC electrode positive
B AC electrode negative
C AC with continuous high frequency current
D AC rectified current
using direct current reverse polarity with GTAW:
A. using direct current reverse polarity
B. only works with high frequency current
C. fails to remove oxides from aluminum
D. requires a zirconated tungsten electrode
With the machine running, what is most likely to be the problem when you are unable to start an arc?
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why must metal components be grounded when high frequency current is used?
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high frequency leakage can be prevented by:
A keeping the welding cables as short and straight as possible
B wrapping cables around your neck when welding
C keeping the cables coiled together
D using a long, diameter torch cable
what can happen if the torch body or handle becomes cracked
water pressure on a GTAW torch should NOT exceed:
A. city supplied water pressure
B. the CSA rating for the hose fittings
C. the pressure required for circulation
D. the manufacture recommendations
the end of the gas nozzle must be kept clean and uniform in order to avoid:
A. deep penetration
B. uneven gas coverage
C. arc wandering across the puddle
D. undercutting at the bead edges
metal particles sticking to the inside of the ceramic nozzle may:
A. causes the tungsten electrodes to overheat
B. causing a short circuit between the tungsten electrode and the nozzle
C. causes gas turbulence and possible between the tungsten and possible atmospheric contamination
D. impede the flow of electrons from the tungsten
why must collets be kept clean?
A GTAW electrode that discolours when the arc is broken is an indication that:
A. excessive current was used
B. low amperage was used
C. post flow time is long
D. the electron has atmospheric contamination
If you Strick an arc and immediately experience atmospheric atmospheric contamination, what part of the equipment may not be properly adjusted?
_________________
What can happen if the torch body or handle becomes cracked?
______________________
What may occur if thee gas hose fittings are not tightly secured?
why should the gas and coolant hoses be encased in a protective cover?
what is the likely cause of porosity in a GTAW weld?
A. inadequate electrodes extension
B. excessive back purge pressure
C. inadequate gas shielding
D. improper joint fit up
excessive shielding gas flow may resalt in:
A. contamination of the weld puddle
B. a stable arc at low welding currents
C. contamination of the tungsten
D. wider heat affected zones
contained shielding gas generally causes:
A. porosity
B. cracks
C. lack of fusion
D. undercute
what shielding gas is the best choice to aid in oxide removal on aluminum? Why?
why is argon-hydrogen shielding not recommended for carbon steels?
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GTAW trouble shooting can be grouped into one of which three categories
A_____________
B_____________
C____________-
