What parameter primarily controls weld penetration in SMAW?

• A. Voltage
• B. Current
• C. Resistance
• D. Gas flow

Answer: (B)

In SMAW, how deeply the weld penetrates is mainly governed by the heat delivered by the arc. That heat is set mostly by the welding current. Higher current produces a hotter arc, melts more base metal, and pushes the weld pool deeper into the joint, while lower current yields shallower penetration. Voltage influences the arc length and bead shape, but it doesn’t change the amount of heat as directly as current does. Gas flow isn’t a factor in SMAW because shielding comes from the flux coating, not an external gas stream. Resistance isn’t an adjustable welding parameter you set to control penetration. So, adjusting the current is the primary way to control how deeply the weld penetrates.