AWS Welding Processes 2

Question 1

In GMAW (MIG welding), what does the term 'short-circuit transfer' describe?

Accepted Answer

The wire electrode periodically contacts the weld pool, causing the arc to extinguish and re-ignite

Answer

Short-circuit transfer occurs when the wire electrode touches the molten pool, extinguishing the arc momentarily before re-igniting as the wire burns back.

Question 2

Which shielding gas is most commonly used for GMAW of carbon steel in the US?

Accepted Answer

75% argon / 25% CO₂

Answer

A 75% Ar / 25% CO₂ mixture (C25) is the most widely used shielding gas for GMAW on carbon steel, providing good arc stability and penetration.

Question 3

What is the primary advantage of the flux-cored arc welding (FCAW) process over solid-wire GMAW?

Accepted Answer

Higher deposition rates and better performance in outdoor/windy conditions

Answer

FCAW provides higher deposition rates than solid-wire GMAW and, with self-shielded variants, can be used outdoors where wind would disrupt external shielding gas coverage.

Question 4

During GTAW (TIG welding), what is the purpose of the high-frequency (HF) start?

Accepted Answer

To initiate the arc without the tungsten electrode touching the workpiece

Answer

HF start ionizes the shielding gas to initiate the arc while the tungsten is still held away from the base metal, preventing tungsten contamination.

Question 5

In submerged arc welding (SAW), what covers the arc and molten metal during welding?

Accepted Answer

A granular flux that completely submerges the arc

Answer

SAW uses a granular flux that covers and submerges the arc, protecting the weld metal, reducing spatter, and allowing very high deposition rates.

AWS Practice Test

AWS Practice Test

AWS Welding Processes 2