Why does travel speed change heat input so much?

Q: What is the welding heat-input formula?

A standard estimate is H(kJ/mm) = ((V × I × 60) / (S × 1000)) × η, where V is voltage, I is amperage, S is travel speed in mm/min, and η is thermal efficiency. The calculator converts in/min to mm/min automatically when needed.

Q: Can this replace WPS/PQR requirements?

No. This is a planning and QA estimate. Production welding still requires qualified procedures and compliance with project code/specification limits for heat input, interpass temperature, and metallurgy controls.

Question

Why does travel speed change heat input so much?

Accepted Answer

Heat input is inversely proportional to travel speed. Slower travel puts more energy into each millimeter of weld, raising heat input, while faster travel lowers energy per unit length.

Why does travel speed change heat input so much?

Answers