456A MIG/FCAW (GMAW & Flux-Cored Arc Welding) 2

Question 1

What is the difference between FCAW-S (self-shielded) and FCAW-G (gas-shielded) flux-cored welding?

Accepted Answer

FCAW-S uses flux in the core to generate its own shielding; FCAW-G requires an external shielding gas in addition to the flux core

Answer

FCAW-S electrodes contain flux ingredients that generate all necessary shielding gases and slag without external gas, making them ideal for outdoor/field welding where wind would disperse external shielding. FCAW-G electrodes use a combination of flux core and external shielding gas for better weld quality and lower fume generation.

Question 2

What is the travel angle and work angle convention for GMAW in the flat position?

Accepted Answer

Work angle 90° to the joint; travel angle 5–15° drag (backhand)

Answer

For flat position GMAW, the work angle is 90° perpendicular to the joint (or split equally for fillet welds at ~45°), and the travel angle is a 5–15° drag (backhand/trailing) angle pointing back toward the completed weld. This provides good visibility of the weld pool and proper penetration.

Question 3

What does 'wire stick-out' (contact tip-to-work distance) affect in GMAW?

Accepted Answer

Current draw and deposition rate — longer stick-out reduces current and deposition rate

Answer

Wire stick-out (the distance from contact tip to workpiece) affects resistance heating of the wire. Longer stick-out increases resistance, preheats the wire, and reduces the actual welding current drawn for the same wire feed speed, lowering penetration and deposition rate. Shorter stick-out increases current and penetration.

Question 4

What is 'spatter' in GMAW and what is the primary cause when using C25 shielding gas?

Accepted Answer

Small droplets of metal expelled from the arc; caused by incorrect voltage/amperage settings or contaminated base metal

Answer

Spatter consists of small molten metal droplets expelled from the arc that solidify on the base metal or nozzle. In GMAW with C25, the primary causes are voltage too low or too high relative to wire feed speed, arc instability from contamination, or improper inductance settings. Spatter is non-fused and does not contribute to weld strength.

Question 5

Which GMAW transfer mode is recommended for welding out-of-position (vertical, overhead)?

Accepted Answer

Short-circuit transfer

Answer

Short-circuit transfer uses lower heat input and produces a smaller, more controllable weld pool that solidifies quickly, making it suitable for out-of-position welding. Spray transfer produces a large, fluid weld pool that is difficult to control in vertical or overhead positions. Pulse spray can also be used out of position.

Red Seal Welder 456A Practice Test

Red Seal Welder 456A Practice Test

456A MIG/FCAW (GMAW & Flux-Cored Arc Welding) 2