What is the effect of increasing wire feed speed on a MIG weld bead if all other settings remain constant?

• A. Decreased deposition rate and narrower bead
• B. Increased deposition rate and wider, taller beads
• C. No change to bead geometry
• D. Reduced heat input

Answer: (B)

Increasing wire feed speed raises the welding current, so more filler metal is deposited per second. With constant voltage and other settings, this higher current heats the pool more, causing the molten metal to spread and fill a wider area while also building up more height. In other words, deposition rate goes up and the bead becomes wider and taller. The bead does not narrow or stay the same, and heat input does not decrease when the wire feed speed increases.