Which current type is typically used to minimize arc blow in SMAW?

• A. Direct current (DC)
• B. Pulsed current
• C. Alternating current (AC)
• D. Constant current (CC)

Answer: (C)

Alternating current is typically used to minimize arc blow in SMAW because the current reverses polarity every half cycle, which reverses the magnetic field around the arc and workpiece. That changing field cancels out the steady pull that would otherwise push the arc in one direction, keeping it more centered on the weld. Arc blow tends to happen more with a steady polarity, especially on ferromagnetic metals or near clamps, so the rapid polarity reversal of AC helps prevent the arc from wandering.

Direct current maintains a single polarity, creating a steady magnetic field that can drive arc blow and cause drift. Pulsed current can help control heat and penetration but doesn’t reliably cancel the magnetic effects that cause arc blow. Constant current stabilizes the current level but doesn’t specifically address the arc blow mechanism.