Weld Heat Input Calculator

Weld Heat Input Calculator

Heat input directly controls the metallurgical properties of a finished weld - this calculator applies the standard AWS formula used across the welding industry.

Heat Input (J/mm) = (Voltage × Amperage) / Travel Speed (mm/sec)

Example

24V, 180A, 300 mm/min travel speed:

Travel Speed = 5.0 mm/sec → Heat Input = (24 x 180)/5.0 = 864 J/mm (0.864 kJ/mm)

Why Heat Input Range Matters

Too little heat input can cause incomplete fusion or excessive hardness and brittleness in certain steels (particularly higher-carbon or alloy steels prone to rapid cooling effects), while too much heat input can cause excessive grain growth, reduced toughness, or unwanted distortion in the finished part.

Welding Procedure Specifications

Welding Procedure Specifications (WPS) for critical structural or pressure vessel work typically specify an acceptable heat input range that must be maintained throughout production welding - this calculator lets welders verify their actual parameters (voltage, amperage, and travel speed) fall within that qualified range before and during production welding.