Welding heat input formula?

Q = (V × I × η × 60) / (S × 1000) kJ/mm

Typical arc efficiency η?

SMAW: 0.7–0.85 | MIG: 0.8–0.9 | TIG: 0.6–0.8 | SAW: 0.9–1.0

AutoEngCalc - Engineering Calculators

Calculate welding heat input Q in kJ/mm or kJ/inch. Includes arc efficiency, preheat/interpass temperature guidance for carbon and stainless steels.

Heat Input Q

1.44 kJ/mm

300A, 30V, 300 mm/min

Featured: Q kJ/mm • Preheat • Interpass • Efficiency

Welding Process

Current I (A)

Voltage V (V)

Travel Speed (mm/min)

Arc Efficiency η

Units

Common limits for steels

Q = (V × I × η × 60) / S (kJ/mm)
Q = (V × I × η × 60) / (S × 25.4) (kJ/inch)

Enter welding parameters to see results

SMAW: 0.70–0.85

MIG/GMAW: 0.80–0.90

TIG: 0.60–0.80

SAW: 0.90–1.00

Carbon Steel: 1.0–2.5 kJ/mm

High Strength: ≤1.5 kJ/mm

Stainless: 0.5–1.5 kJ/mm

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