What happens to heat input if travel speed decreases while current and voltage stay the same?

What happens to heat input if travel speed decreases while current and voltage stay the same?

• A. Heat input increases
• B. Heat input decreases
• C. Heat input stays the same
• D. Heat input varies unpredictably

Answer: (A)

Heat input is the energy delivered into the weld per unit length. With voltage and current held constant, slowing down the travel speed means the arc spends more time heating each spot along the weld. Since heat input is effectively inversely related to travel speed, reducing speed increases the heat input. In other words, moving slower delivers more energy per inch of weld, so the overall heat put into the weld rises. If you cut speed in half, the heat input per inch roughly doubles, assuming other factors stay the same.

Heat input is the energy delivered into the weld per unit length. With voltage and current held constant, slowing down the travel speed means the arc spends more time heating each spot along the weld. Since heat input is effectively inversely related to travel speed, reducing speed increases the heat input. In other words, moving slower delivers more energy per inch of weld, so the overall heat put into the weld rises. If you cut speed in half, the heat input per inch roughly doubles, assuming other factors stay the same.