Exam 16: Gas Tungsten Arc Welding Equipment, Setup, and Operation

____________________ is a by-product of the natural gas industry that is removed from natural gas as the gas undergoes separation for purification or refinement.

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

____________________ is the time during which the gas continues flowing after the welding current has stopped.

Explain how tungsten electrodes are produced.

____ electrodes have a current-carrying capacity similar to that of pure tungsten, and may be used for both AC and DC welding currents.

The improved electron emission of the ____ allows it to carry approximately 20% more current than pure tungsten.

Why is an inert shielding gas required for GTA welding?

With ____, penetration and bead profile are sensitive to arc length, and the long arcs needed for feeding filler wires are more difficult to control.

In GTAW, the arc temperature is around ____ Fahrenheit.

Flowmeters measure the flow rate of a shielding gas in __________units.

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

The ____ protects the molten weld pool, the filler rod, and the tungsten electrode as they cool to a temperature at which they will not oxidize rapidly.

When the shielding gas flow rate is high, air is drawn into the gas envelope by a(n) ____________________ effect around the edge of the nozzle.

Adding ____ has the same effect on the electrode characteristic as thorium, but it is not radioactive.

____________________, when added in percentages of up to 0.6 percent to tungsten, improves its current-carrying capacity.

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

Explain why the heat of the arc, which is much higher than the melting point of tungsten, does not actually melt the tungsten electrode.

What is the purpose of a gas lens?

What is the most likely explanation for why DCEP has a cleaning action?

The squarewave provides the welder with a current that allows the molten weld pool to _______________.