How do amperage and voltage affect a weld bead in GMAW and SMAW?

How do amperage and voltage affect a weld bead in GMAW and SMAW?

• A. Amperage controls speed of the welding machine's travel; voltage controls arc color
• B. Amperage controls heat input and bead size; voltage controls arc characteristics and penetration
• C. Amperage controls filler metal composition; voltage controls shielding gas flow
• D. Amperage controls torch speed; voltage controls temperature of the environment

Answer: (B)

Heat input and arc behavior determine how the weld bead forms. Amperage is the current driving the arc, so it mainly sets how much heat is delivered to the metal. More current means more heat, which melts more metal, producing a larger bead and greater penetration (though too much heat can cause burn-through or an oversized bead). Voltage sets the electrical potential across the arc, which controls the arc length and how the heat is distributed. A higher voltage generally lengthens the arc, leading to a wider, flatter bead with shallower penetration, while a lower voltage concentrates the heat, creating a narrower bead with deeper penetration. This influence on arc characteristics and penetration applies to both GMAW and SMAW, with voltage also affecting arc stability and transfer behavior in GMAW. So, amperage governs heat input and bead size; voltage governs arc characteristics and penetration.

Heat input and arc behavior determine how the weld bead forms. Amperage is the current driving the arc, so it mainly sets how much heat is delivered to the metal. More current means more heat, which melts more metal, producing a larger bead and greater penetration (though too much heat can cause burn-through or an oversized bead).

Voltage sets the electrical potential across the arc, which controls the arc length and how the heat is distributed. A higher voltage generally lengthens the arc, leading to a wider, flatter bead with shallower penetration, while a lower voltage concentrates the heat, creating a narrower bead with deeper penetration. This influence on arc characteristics and penetration applies to both GMAW and SMAW, with voltage also affecting arc stability and transfer behavior in GMAW.

So, amperage governs heat input and bead size; voltage governs arc characteristics and penetration.