202a Flashcards by Shane Halbert

Define the term GTAW.

Gas tungsten arc welding (GTAW), often referred to by its non-preferred term TIG, is a process in which fusion welding is accomplished by the heat of an electric arc drawn between a non-consumable tungsten electrode and work the work. the electrode, arc, weld puddle and the adjacent heated area of the workpiece are protected from athospheric contamination by an externally applied gaseouse shield. filler rod may or atmospheric contamination by an externally applied gaseous shield. filler rod may or may not be added.

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with GTAW, the heat of the arc is transferred to the work through a non-consumable:

A. titanium electrode
B. carbon electrode
C. tungsten electrode
D. ceramic electrode

C. tungsten electrode

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GTAW requires an inert gas to:

A. shield the weld puddle.
B. cool the ceramic cup.
C cool the base metal.
D. reduce current resistance across the ark.

A. shield the weld puddle.

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GTAW is used primarily when:

A. high deposition rates are required.
B. high heat input is desirable.
C. welding on think materials
D. high quality welds are mandatory

D. high quality welds are mandatory

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For what application would hot wire GTAW be used?

A. where high production welds are required
B. for square butt joints on thin wall tubing
C. for the joining of precision parts
D. where weld quality is of concern

A. where high production welds are required

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state the major differences between hot wire GTAW and cold wire GTAW.

Hot wire GTAW has the wire preheat with an auxiliary AC current prior to the wire entering the weld pool, whereas the cold wire process feeds wire that is at at ambient temperature and without an auxiliary port

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In what positions can the GTAW process be used?

A. Flat only
B. Flat and horizon only
C. vertical only
D. all positions

D. all positions

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which metal requires a full preheat when welded with the GTAW process?

A. aluminum
B. Carbon steel
C. Magnesium
D. Cast iron

D. Cast iron

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GTAW has an advantage over SMAW
because it:

A. reduces the overall cost of welding
B. can eliminate the need to use a flux
C. does not require a skilled operator
D. uses inexpensive welding equipment

B. can eliminate the need to use a flux

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the intensity of ultraviolet light produced by the GTAW process is like ______ metal arc welding, but is greater than that produced by the _______ metal arc welding process.

the intensity of the ultra violet light produced by the GTAW process is like gas metal arc welding, but is much greater than that produced by the shielded metal arc welding

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when welding with GTAW, you should wear:

A. dark-coloured, tightly woven clothing.
B. light-coloured, open mesh clothing.
C. light-coloured, heavy weight clothing.
D. dark-coloured, synthetic fabric clothing. [

A. dark-coloured, tightly woven clothing.

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when using GTAW, good ventilation is required to prevent:

A. gamma radiation poisoning.
B. an oxygen deficient.
C. smoke inhalation.
D. explosive gas mixes.

B. an oxygen deficient.

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The arc radiation from GTAW, good ventilation is required to prevent:

A. CO (carbon monoxide).
B. CO2 (carbon dioxide
C. O3 (ozone)
D. SO2 (sulphur dioxide)

C. O3 (ozone)

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Ultraviollet radiation from GTAW can react with chorinated degreasing solvents to produce

A. phosgene gas.
B. Sulphur dioxide gas.
C. ammonia gas
D. ozone gas

A. phosgene gas.

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pulsing the arc with GTAW is an advantage when:

A. a wide heat-affected zone is required.
B. penetration on thin metals must be controlled.
C. maximum bead width is preferred.
D. high current settings must be used.

B. penetration on thin metals must be controlled.

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Welding machines designed for GTAW are:

A. constant voltage (CV).
B. rising voltage (RV).
C. Constant potential (CP).
D. constant current (CC)

D. constant current (CC)

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Which statement is true with respect to orbital GTAW?

A. filler wires must always be added.
B. it can be done without filler wires.
C. the Pipe turns while the arc is fixed.
D. it is less productive than manual welding.

B. it can be done without filler wires.

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which of the following machines would be suited for GTAW?

A. AC transformers.
B. DC generator
C. AC/DC rectifier
D. AC alternator

C. AC/DC rectifier

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power sources recommended for GTAW have a ___________________ volt-amp curve.

steep drooping

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A post purge control is designed to:

A. keep gas flowing for a preset time after the arc is extinguished.
B. protect the filler rod from out side contaminates
C. Increase the cooling rate of deposited metal
D. increase the gas flow when filling weld crater

A. keep gas flowing for a preset time after the arc is extinguished.

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What is recommended size of electrode when using 125 amperes on:

a AC current _______
b DCEN ________
c DCEP ________

A 2.5mm (3/32)
B 1.6 mm (1/16)
C 6.4 mm (1/4 )

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what is the recomended current type for welding stainless steel?
_______________________

DC electrode negative

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which current type produce the deepest penetration?

A. alternating current with continuous high frequency.
B. alternating current with high frequency.
C. direct current electrode positive.
D. direct current electrode negative.

D. direct current electrode negative.

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removal of aluminum oxide occurs:

A. during the positive half of the AC cycle
B. when high frequency current is activated
C. on the straight polarity setting of a DC machine.
D. with the addition of a fully deoxidized filler metal

A. during the positive half of the AC cycle

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AC high frequency is most suited for GTAW on: A. aluminum and carbon steel. B. stainless steel and nickel alloys. C. aluminum and magnesium D. cast iron and copper

C. aluminum and magnesium

Continuous high frequency current is required when: A. DCSR is used B. the electrode is ground to sharp point C. a stabilized ac current is required D. it is necessary to increase

C. a stabilized ac current is required

which statement is true with respect to square waves? A. The EP portion is always greater. B. The EN portion is always greater. C. The EP and EN portions must be equal D. The EP and EN portion can be adjusted

D. The EP and EN portion can be adjusted

Why should the torch cables be kept as short as possible when using GTAW?

to help prevent the loss of high frequincy current as it travels from the machine to electrode.

A GTAW torch that is too small for the current settings overheats the __________.

torch body

A torch cap is the part of GTAW torch that: A. reduces amperage loss B. protects the electrode from accidental arc strikes C. keeps electrode clear and cool D. controls electrode contamination

B. protects the electrode from accidental arc strikes

a Collet is a device in the GTAW torch that: A. the ceramic cup that attaches to for a gas tight seal B. protects the electrode from accidental arcing inside the torch head. C. allows the shielding gas flow meter setting D. positions the eletrode and transfers current

D. positions the eletrode and transfers current

To use continues high frequency current, the nozzle must be constructed of: A. copper B. brass C. stainless steel D. ceramic

D. ceramic

the diameter of the nozzle is normally determined by: A. your ability to see the molten puddle B. the size of the puddle and the electrode C. the shielding gas flowmeter setting. D. the voltage range and polarity set at the machine

B. the size of the puddle and the electrode

what is the purpose of a requlator when used with GTAW? A. to reduce supply pressure to a safe working pressure B. to meter the flow of shielding gas C. to reduce the flow shielding gas D. to reduce the surface pressure at the nozzle

A. to reduce supply pressure to a safe working pressure

A flowmeter is calibrated in: A. litter per hour or cubic inches per hour B. litter per minute or cubic feet per hour C. liters per minute or cubic feet per minute D. litters per minute or cubic inches per hour.

B. litter per minute or cubic feet per hour

what is the purpose of a flowmeter when used with GTAW? A. to reduce the supply pressure to a safe working pressure B. to meter the flow of shield gas C. to control the post-flow time of shielding gas D. to reduce the line pressure of shielding gas

B. to meter the flow of shielding gas

A floating type flow meter must be used in the _____________ position

vertical

what type of hose is recomended when using helium shielding gas?

plastic!

what are the advantages of using orbital GTAW? A ______________________ B ______________________ C ______________________ D ______________________ E ______________________

A increase productivity compaired to manual welding. B superior weld quality consistency to that of manual welding, C one a certified welder has set up the parameters, someone else can operate it, D may be the only solution where pipe cannot be rolled and E well suited fir applications where physical access is limited

what does GTAW stand for? A. gas tungsten arc welding B. general tungsten alloy welding C. Gas transmission and arc welding D. GTA Welding technique

A. gas tungsten arc welding

what is one main purpose of a gas lens in a GTAW torch. A. To increase B. To enhance C. To ensure laminar gas flow D. To secure the electrode

C. To ensure laminar gas flow

which polarity is typically used with GTAW on aluminum and magnesium? A. DCEN B.DCEP C. AC D. DC

A. DCEN

What type of electrode is used in GTAW? A. consumable B. Non-Consumable tungsten C. metal core D. flux coated

B. Non-Consumable tungsten

Which of the following is key advantage of GTAW. A. fast welding speed B. minimal training needed C. high weld quality D. no shielding gas required

C. high weld quality

what is primary hazard of using shield gas in confined space? A. corrosion B. explosion C. Asphyxiation D. Fire

C. Asphyxiation

why is high frequency current used in GTAW? A. To increase gas pressure B. To cool the touch C. To stabilize the arc and assist with starting D. To eliminate the need for filler metal

C. To stabilize the arc and assist with starting

Which shielding gas is commonly used for GTAW. A. oxygen B. Nitrogen C. Argon D. Carbon Dioxide

C. Argon

Which of the following materials can GTAW weld effectively? A. aluminum B. Magnesium C. Stainless Steel D. All of the above

D. All of the above

What does the foot pedal control in GTAW? A. shielding gas flow B. Arc voltage C. Current ( amperage ) D. torch cooling

B. Arc voltage

what is one disadvantage of GTAW compared to other ark welding processes A Fast travel speed B low skill requirement C high deposition rate D slow welding speed

D slow welding speed

which welding current type offers the best cleaning action on aluminum? A. DCEN B. DCEP C. AC D. none of the above

B. DCEP

why is AC current preferred for welding aluminum using GTAW? A it gives deep penetration only B It cools the electrode C it combines cleaning action with penetration D it requires less skill

C it combines cleaning action with penetration

which GTAW process variation uses a mechanized arc that travels 360 degrees around the workpiece? A. cold wire GTAW B. orbital GTAW C. spot welding D. Hotwire GTAW

B. orbital GTAW

which personal protective equipment (PPE) is critical when welding with GTAW? A. Hearing protection B. flash glasses C. TIG gloves D. All of the above

D all of the above

Which current type is rarely used in GTAW due to low electrodes current-carrying capacity? A. Ac B. DCEN C. DCEP D. Square wave

C. DCEP (Rarely)

What is the main function of a solenoid valve in GTAW system? A cool the torch B open gas cylinder C Control gas and coolant flow D Regulate amperage

C Control gas and coolant flow

What feature on GTAW machines prevents oxidation of the tungsten electrode after the arc stops? A. pre-flow timer B. post-purge timer C. AC balance D. Arc starter

B. post-purge timer

which gas nozzle type provides the most arc stability and vision in tight weld spots A. Ceramic B. Metal C. Fused quartz D. Alumina

C. Fused quartz

What is the main benefit of using a water-cooled torch over an air-cooled torch? A. Lower cost B. More portable C. can handle higher amperage D. dose not require coolant

C. can handle higher amperage

What is the recommended gas flow rate range for argon in GTAW? A. 1-3L/min B. 3-7L/min C. 5.8-16L/min D. 20-30L/min

C. 5.8-16L/min

which of the following in NOT a common shielding gas for GTAW? A. Argon B. Helium C. Carbon Dioxide D. Gas mixes

C. Carbon Dioxide

What is the function of a collet in a GTAW torch? A. cool the electrode B. diffuse the the gas C. secure the electrode D. control amperage

C. secure the electrode

what phenomenon resalts in a sunburn-like effect on skin from welding arcs? A. Gas contamination B. Radiation reflection C. Ozone exposure D. Crater cracking

B. Radiation reflection

which is an advantage of GTAW spot welding A. which is an advantage of GTAW spot welding B. Reduce fumes C. it reduces distortion D. limits cracking

C. it reduces distortion

Shielding gas connections on a GTAW torch will have what type of threads A Left handed threads B Coarse threads C Right handed Threads D AC threads

C Right handed Threads (Remember water cooled torches have left handed threads)

what temp does liquid argon exist at?

-302F or -185C

what is a disadvantage of an air-cooled GTAW torch compared to water cooled torch? A the torch will over heat at high currents B increases arc blow C reduces duty cycle D causes more spatter

A the torch will over heat at high currents

What will a GTAW power source with output conductor control allow a welder to do? A starting arc remotely B adjust shielding gas manually C allows current/gas control at remote unit D adjust voltage at machine

C allows current/gas control at remote unit

which clothing is most suitable for GTAW? A. bright denim B. light cotton C. dark colored cotton D. synthetic fabric

C. dark colored cotton

how can a welder prevent the loss of high frequency current? A. keeping welding cables as short as possible B. add insulators C. twist cables D. use long cables

A. keeping welding cables as short as possible

when would continuous high frequency current in GTAW be used? A. the current needed is stabilized AC B. To improve gas flow C. reduce electrodes wear D. prevent overheating

A. the current needed is stabilized AC

What aids in the cooling of air cooled GTAW torch? A. ceramic cups B. shielding gas C. torch fins D. metal lens

B. shielding gas

what temperature can the arc of GTAW reach A. 20,000F B. 35,000F C. 15,000F D. 10,000F

B. 35,000F

what shade of glasses would be suitable when in an area used for GTAW A 10 B 7 C 5 D 2

D 2

what s the general rate of pulsation when using pulsed GTAW? A 1 to 3 times per second B 2 to 10 times per second C 10 to 50 times per second D 20 to 50 times per second

B 2 to 10 times per second

when does high amperage GTAW have an advantage A. joining thick stainless B. welding root passes on carbon steel pipe C. overhead welds on mild steel D. tack welding aluminum

B. welding root passes on carbon steel pipe

what is the primary job of a shielding gas when used with GTAW? A cool the weld zone B eliminate atmospheric contamination of weld puddle C eliminate atmospheric contamination D reduce arc blow

B eliminate atmospheric contamination of weld puddle

what give GTAW an advantage over SMAW? A can eliminate the need to use a flux B requires flux for cleaning C allows use of flux D reduces slag formation

A can eliminate the need to use a flux

if high frequency current was not available on a CC GTAW Power supply, which of the following metals would be impartial to weld? A mild steel B low carbon steel C Aluminum D Titanium

C Aluminum ( high frequency is AC)

when welding aluminum with GTAW, what causes arc rectification? A. low heat input B. poor puddle visibility C. surface oxides on work D. gas turbulence

C. surface oxides on work

gas nozzles for GTAW are numbered according to which dimension? A inside diameter B thread pitch C outside diameter D nozzle length

A inside diameter

why does rectification occur, when welding aluminum with the GTAW process A poor puddle visibility B low heat input C surface oxides on parent metal D gas turbulence

C surface oxides on parent metal

voltage is the pressure needed to push the amperage through the conductor: A. sometimes B. not applicable C. false D. true

D. true

which gas will be formed by the reaction between GTAW ultraviolet light and air? A. carbon monoxide B. helium C. argon D. O3 (ozone)

D. O3 (ozone)

which of the following combinations are suitable for welding medium carbon steel pipe with GTAW? A. direct current straight polarity B. increase deposition rate C. improve arc initiation D. Reduces porosity

A. direct current straight polarity

it is essential to use plastic hoses for transporting which type of shielding gas? A. helium B. argon C. CO2 D. nitrogen

A. helium

when using high frequincy current with GTAW, the current has the following 3 (three) important functions: 1 2 3

1 arc stabilizing (re-ignition positive half cycle of alternating current) 2 arc initiation (non-touch starting) 3 gas ionization (aid starting promotes cleaning action)

202a Flashcards

the GTAW process (88 cards)