What factor related to welding gun movement directly affects heat input?

• A. Shielding gas
• B. Travel speed
• C. Electrode diameter
• D. Electrode color

Answer: (B)

Heat input is governed by how long the arc energy stays in a given spot, which is directly controlled by how fast you move the welding gun along the joint. When you travel slowly, the arc spends more time on a small area, delivering more energy per inch and producing higher heat input (deeper penetration and a hotter weld). Move the gun faster and the arc spends less time in one location, reducing heat input and typically yielding a cooler weld with shallower penetration. Shielding gas mainly protects the weld pool and does not change the energy delivered; electrode diameter can influence the current setting and thus energy, but the direct, movement-related factor that alters heat input is travel speed; electrode color has no bearing on heat input.