Which of the following is true of grinding tungsten electrodes? - ✔️✔️If the grinder is
used for the metals other than tungsten, particles of these metals may become trapped
on the tungsten as it is ground, resulting in contamination when the arc is started.
The improved electron emission of the _____ allows it to carry approximately 20% more
current than pure tungsten. - ✔️✔️Thoriated tungsten
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. - ✔️✔️Postflow period
Which of the following is true of erosion of the tungsten electrode? - ✔️✔️Slow erosion
results in limited tungsten inclusions in the weld.
Which of the following is a way to minimize erosion of the tungsten electrode? -
✔️✔️Use DCEN current
Which of the following is true of DCEN? - ✔️✔️With DCEN, a pointed tip concentrates
the arc.
Which of the following is true of DCEP? - ✔️✔️DCEP has the highest heat
concentration on the electrode tip.
In GTAW, the arc temperature is around _____ Fahrenheit. - ✔️✔️11,000
Adding _____ has the same effect on the electrode characteristics as thorium, but it is
not radioactive. - ✔️✔️Zirconium
______ electrodes have a current-carrying capacity similar to that of pure tungsten, and
may be used for both AC and DC welding currents. - ✔️✔️Cerium tungsten
Which of the following is true of breaking and remelting tungsten? - ✔️✔️It should be
broken squarely
DCEP concentrates _____ of the arc heat on the plate, and _____ of the heat in the
electrode. - ✔️✔️1/3, 2/3
DCEN concentrates about _____ of its welding heat on the work, and about ____ on the
tungsten. - ✔️✔️2/3, 1/3