Heat Input Calculator

Calculate the energy transferred to the base metal during welding. Critical for maintaining material strength and avoiding Hydrogen-Induced Cracking (HIC) or excessive distortion.

Welding Parameters
A
V
Calculated Heat Input
Gross Heat Input

0.00

kJ/in
(Ignores Process Losses)
Net Heat Input

0.00

kJ/in
(Adjusted for 80% Efficiency)
Why Measure Heat Input?

Heat input strongly influences the cooling rate of the weld. It dictates the metallurgical properties of both the weld metal and the Heat Affected Zone (HAZ).

The Formula
$Q = \frac{V \times I \times 60}{v \times 1000}$
Q = Heat (kJ), V = Volts, I = Amps, v = Travel Speed
Too Much Heat (High Q)
  • Causes excessive grain growth, reducing toughness and yield strength.
  • Leads to severe distortion and warping of the assembly.
  • Can destroy the heat-treatment (T6, etc.) of aluminum alloys.
Too Little Heat (Low Q)
  • Causes a rapid cooling rate (quenching effect).
  • Creates hard, brittle microstructures like Martensite in carbon steels.
  • Increases the risk of Hydrogen-Induced Cracking (Cold Cracking).
AWS/ASME Note: Some structural welding codes refer to "Gross" heat input (ignoring thermal efficiency), while advanced engineering requirements often specify "Net" heat input to account for the arc efficiency of the specific process.