ua chapter 18

The electrode positive part of the AC cycle produces a cleaning action that removes the oxide coating on aluminum.

• true

• false

Stainless steels, especially those in the 300 austenitic series, are commonly welded with GTAW using DCEP.

• true

• false

High-carbon steels are weldable but require preheat and postheating.

• true

• false

Filler metals for welding stainless steels are alloyed to prevent cracking problems.

• true

• false

When welding, the fumes from copper and copper alloys can be toxic.

• true

• false

Wrought aluminum alloys in the ___ series are readily weldable.

• 2000

• 3000

• 6000

• 7000

A forehand welding technique usually produces the best results when welding copper and copper alloys.

• true

• false

The procedure for welding all types of stainless steels with GTAW is the same.

• true

• false

The welding characteristics of magnesium are comparable to those of carbon steel.

• true

• false

When welding aluminum with GTAW, the best results are obtained by using ___ shielding gas.

• 75% argon 25% CO2

• 98% Argon @% CO2

• 100% helium

• 100% argon