AWS Gas Metal Arc Welding (GMAW/MIG) 4

Question 1

In GMAW, what is the primary purpose of using a push angle (forehand) technique compared to a drag angle (backhand) technique?

Accepted Answer

Produces shallower penetration and wider, flatter bead

Answer

A push (forehand) angle directs heat forward, resulting in shallower penetration and a wider, flatter bead profile.

Question 2

Which GMAW transfer mode is characterized by the wire tip never actually touching the base metal, with metal crossing the arc as fine droplets?

Accepted Answer

Spray transfer

Answer

Spray transfer occurs above a critical current threshold where metal transfers as a fine axial spray across the arc without contact with the base metal.

Question 3

What condition causes 'cold lapping' (lack of fusion) at the toes of a GMAW weld?

Accepted Answer

Excessive travel speed with insufficient heat input

Answer

Cold lapping occurs when travel speed is too fast or heat input is too low, preventing the weld metal from properly fusing with the base material at the toes.

Question 4

When welding aluminum with GMAW, which polarity and shielding gas combination is standard practice?

Accepted Answer

DCEP with 100% argon

Answer

DCEP (electrode positive) with 100% argon is standard for GMAW on aluminum because DCEP provides cathodic cleaning action that removes the oxide layer.

Question 5

A welder notices the weld bead has excessive spatter and an irregular, convex profile. Which parameter adjustment is most likely needed?

Accepted Answer

Increase voltage

Answer

Excessive spatter and a convex bead profile typically indicate voltage is too low; increasing voltage widens and flattens the bead while reducing spatter.

AWS Practice Test

AWS Practice Test

AWS Gas Metal Arc Welding (GMAW/MIG) 4