GTAW Study Guide (TIG)

___________ additions are restricted to stainless steels because it is the primary cause of porosity in aluminum welds.

Hydrogen

The gas preflow and postflow times depend on which of the following?

Nozzle size

The most common types of contaminants are ______

Oil, Dirt, Oxides

When the parts are clamped in place for he AWS SENSE workmanship samples, what must you check before making tack welds?

Proper root gap

_______ has the poorest heat resistance and electron emission characteristic of all the tungsten electrodes

Pure Tungsten

In the GTAW process, contamination left of the metal will be deposited in the weld because __________.

There is no flux to remove it.

Why would a welder need to make a list of machine settings?

To make is easier to reset the machine for different set-ups.

Which of the following is a way to minimize erosion of the tungsten electrode?

Using DCEN Current

How must tube- and ball-type flowmeters be mounted?

Vertically straight up

The useful life of a ceramic nozzle is affected by the ________.

Current level and proximity to the work

After passing a visual inspection, what mechanical test is next used on the 2G or 6G pipe test specimen?

Guided bend test

Which of the following is an inert gas?

Helium

Which of the following is true of grinding tungsten electrodes?

If the grinder is used for something else other than the tungsten, contamination of that metal can contaminate the tungsten if it is used on the grinder.

If the end of the filler rod is removed from the shielding gas protection ____________.

It will oxidize rapidly

Using a __________ arc current setting with ________ travel speeds is important when welding stainless steel.

Lower, Faster.

The ______ possible gas flow rates and the ______ preflow or postflow time can help reduce the cost of welding.

Lowest and Shortest

Tungsten electrodes that contain elements such as lanthanum or yttrium are referred as _________.

Rare Earth Tungsten

What is the purpose of a gas lens?

Reduce turbulence in the shielding gas.

Welds on stainless steel ____________ than welds on mild steel.

Show contamination easier.

Why does the return water on a water cooled GTAW torch flow out around the power cable?

So a smaller power cable can be used

Why is it important to keep your hands and gloves clean and oil free?

They can recontaminate the base metal or filler.

In GTA welding, the torch may be angled __________ for better visibility.

0-15 degree from perpedicular

AC concentrates about _____ of it's welding heat on the work and _______ on the tungsten.

1/2 and 1/2

What is the minimum acceptance criteria of undercut for visual inspection of tubing weld?

1/32 in

What is the minimum acceptance criteria for root reinforcement for visual inspection of butt welds?

1/8 in or 3.2mm

After the surface of an aluminum AWS Sense workmanship sample has been cleaned, it should be welded with ________ minutes.

10 minutes

A ________ degree angle or less to the plate surface prevents air from being pulled into the welding zone behind the rod.

15 degree torch angle

What materials must be cleaned off the stainless steel AWS SENSE workmanship samples during preparation of the base metal?

All of the Above

Why might it be necessary to reclean the surface of an aluminum AWE SENSE workmanship sample? 2

All of the Above 2

With ______, surface tension helps hold the metal in place, giving excellent bead contour.

Aluminum

With ___________, cleanliness is a critical factor.

Aluminum

________ is relatively easy to ionize and this is suitable for alternating - current applications and easier starts.

Argon

An Oxide layer on aluminum is _______, while on iron it is __________.

Black, Reddish

Flowmeters measure the flow rate of a shielding gas in ____ units.

CHF or L/min

Which of the following is true of DCEP?

DCEP has the highest heat concentration

Which tyoe of tungsten electrode does not break evenly when trying to break off contamination?

EWLA-1 (Lanthium)

What should be done to the end of the filler rod if it becomes oxidized?

End of the rod should be clipped off.

Before welding on the AWS SENSE workmanship sample, what temperature must a plain carbon steel part be above?

50 degrees F

Carbide precipitation is the combining of ______/

Carbon with dromium

Exceeding the maximum gas flow rates ______.

Cause contamination into the weld