GTAW And Plasma Quiz Flashcards by Michael Lund

Why is GTAW popular?

High quality welds

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The electrode, arc, weld puddle and the adjacent heated area of the workpiece are protected from atmospheric contamination by an externally applied gaseous shield. What gas is used?

Argon

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Advantages of GTAW

-Can join most metals
-High quality
-good control
-uses mostly bare filler metals avoiding flux
-filler metal is not always required
-clean and quiet

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When welding with GTAW what metals are welded with AC?

Aluminum and magnesium

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When welding with GTAW what metals are welded with DCEP

Ferrous metals

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When welding with GTAW what metals are welded with DC reverse polarity?

Non-ferrous

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What are remote control units popular additions to the GTAW workstation

gas flow, cooling media, and current can be controlled at the work point rather than only at the machine.

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What carries more current? Air cooled torch or water cooled torch?

Water cooled

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What is the maximum amount of amps that can be used in an air cooled torch?

200 amps

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What is the use of the torch cap?

Prevents accidental arcing to metal

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What does the torch handle consist of?

The torch assembly normally includes cables, hoses, and machine connectors.

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What is the purpose of the collet body?

Holds electrode in place, establish electrical contact between torch body and electrode collet, and direct shielding gas

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What are are two functions of the electrode collet?

effective in positioning and making positive electrode contact.

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What are most collets made out of?

Copper alloy

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How to identify gas nozzle sizes?

1 1/16” increments. #8 would be 8/16” or 1/2”

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What are gas nozzles commonly made out of?

Ceramic

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What does the lens do to the gas flow?

Causes it to flow in a laminar fashion (arranged thin layers)

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What tungsten electrode is used for welding aluminum? Colour code?

Zirconium oxide - brown

the American Welding Society (AWS) has developed a standard system to classify GTAW electrodes. What is it?

A number and colour code system

How much heavier than air is argon? Helium?

1.4 times heavier than air, 10 times heavier than helium

Pros of using argon?

-has lower arc voltage at any given current value and arc length
-promotes the most efficient cleaning action when using AC on aluminum and magnesium,
-costs less
-has greater availability,
requires lower flow rates than others for good shielding, has better cross-draft resistance, and has easier arc starting and arc stability.

When would you use helium as a shielding gas?

When welding overhead

What is the mixture ratio of argon to helium when using a combination of the two?

80% argon 20% helium

What is a common gas pressure for welding metal projects?

20 cubic feet per hour

Do regulators control flow rates?

No, regulators control pressure

How to identify different filler metals? Carbon steel? stainless steel? Aluminum?

The number of digits in each code. Carbon steel -2 digits. Stainless steel- 3. Aluminum -4

Direct current electrode negative (DCEN) is sometimes called what?

Straight polarity (DCSP)

How should you grind your tungsten for best electrical flow?

Longitudinal to a point

What are some characteristics to consider when welding aluminum?

• coating of aluminum oxides, • electrical and thermal conductivity, • mechanical properties, and • melting point.

What should you do before starting to weld a project?

Ensure the fit is tight without spaces or gaps

Most layout programs for fittings and shapes nest automatically, meaning the parts are laid side by side and rotated to match interlocking angles and contours. Why is this done?

Maximize material useage

What is the importance of being able to design your own labels and reports?

You can later extract critical data for estimating, production, shipping, inventory management and purchasing.

What safety equipment should be worn while using the plasma table?

Gloves, long sleeves and glasses

When wearing g safety glasses while using the plasma table, what shade lenses should be used?

7-9

When looking for a plasma machine, choose a machine that offers…

true/nozzle-in-place safety sensor.

What are the two consumables on a plasma torch?

Nozzle and electrode

The size of a nozzle on a plasma torch should change according to what?

The amps - bigger hole, more power it can handle

What is Kerf?

Kerf is the void created by the plasma cutting process or the amount of metal removed by the plasma

How do operators find the proper kerf compensation value?

Trial and error

What is bevel angle?

The angle of the cut edge

Bevel angle greater than ___ may indicate a problem with PAC machine parameters

5°

What is Dross?

Dross is molten metal from the cut that has re-solidified before it was ejected from the cut

Tool editing component modules allow you to change settings on your tooling to obtain the most desirable results. What parameters are you able to change ?

Kerf, lead in and lead out, and feed rate

What should the bevel angle be on the good and bad side of the cut?

1-3 good side 3-8 bad side