Which GMAW wire would be the best choice for welding scaled or rusty carbon steel?

Which GMAW wire would be the best choice for welding scaled or rusty carbon steel?

• A. ER70S-2
• B. ER70S-6
• C. ER308L
• D. ER4043

Answer: (B)

When welding carbon steel that’s rusty or scaled, you want a filler wire with strong deoxidizers to counter surface contamination. ER70S-6 has higher levels of silicon and manganese, which act as deoxidizers and help the molten metal shed oxygen from rust and scale. That improves weld puddle control, wetting, and reduces porosity, letting the weld fuse more reliably to dirty or oxidized surfaces. The other wires aren’t as well suited for this situation: one is intended for clean carbon steel with fewer deoxidizers, and the remaining two are for stainless steel or aluminum, not carbon steel, so they won’t weld it effectively.

When welding carbon steel that’s rusty or scaled, you want a filler wire with strong deoxidizers to counter surface contamination. ER70S-6 has higher levels of silicon and manganese, which act as deoxidizers and help the molten metal shed oxygen from rust and scale. That improves weld puddle control, wetting, and reduces porosity, letting the weld fuse more reliably to dirty or oxidized surfaces. The other wires aren’t as well suited for this situation: one is intended for clean carbon steel with fewer deoxidizers, and the remaining two are for stainless steel or aluminum, not carbon steel, so they won’t weld it effectively.