Calculation
E = k·U·I·60/(v·1000)
Heat input strongly governs the microstructure and mechanical properties of the heat-affected zone.
Streckenenergie nach DIN EN 1011-1: E = k·U·I/v
Weld heat input (streckenenergie)
Heat input strongly governs the microstructure and mechanical properties of the heat-affected zone.
MINTSI
02
Result
Select a target and calculate.
Understand the inputs
- Heat input E in kJ/mm — Heat actually introduced into the workpiece per unit weld length.
- Thermal efficiency k — Process-dependent efficiency; MMA/MAG about 0.8, SAW about 1.0, TIG about 0.6.
- Welding voltage U — Arc voltage during welding.
- Welding current I — Welding current during welding.
- Welding speed v — Travel speed of the arc along the joint.
Example
k=0.8, U=28 V, I=250 A and v=300 mm/min give E=0.8·28·250·60/(300·1,000)=1.12 kJ/mm.
Assumptions and limits
Steady arc welding with constant process parameters; multi-pass welding, preheat, interpass temperature and process-specific efficiency scatter are excluded.
Understand Weld heat input (streckenenergie)
This calculator determines the heat input of an arc weld, one of the most important process variables for microstructure and mechanical properties of the joint.
What does this quantity describe?
The arc's electrical power U·I is related to weld length via welding speed v; a process-dependent thermal efficiency k accounts for how much of it is actually introduced into the workpiece: E=k·U·I/v.
Formula and variables
E = k·U·I·60/(v·1000)
E = k·U·I/v
| Symbol / input | Meaning |
|---|---|
| Heat input E in kJ/mm | Heat actually introduced into the workpiece per unit weld length. |
| Thermal efficiency k | Process-dependent efficiency; MMA/MAG about 0.8, SAW about 1.0, TIG about 0.6. |
| Welding voltage U | Arc voltage during welding. |
| Welding current I | Welding current during welding. |
| Welding speed v | Travel speed of the arc along the joint. |
Choose the inputs correctly
k is the welding process's thermal efficiency, U the arc voltage, I the welding current and v the welding speed.
How to use the calculator
Take U and I from the set welding parameters, v from the travel speed; choose k by process (MMA/MAG about 0.8, SAW about 1.0, TIG about 0.6).
Worked example
k=0.8, U=28 V, I=250 A and v=300 mm/min give E≈1.12 kJ/mm.
Understand the result and units
Excessive heat input coarsens the microstructure and reduces toughness and strength in the heat-affected zone; too little can cause insufficient penetration.
U is a voltage, I a current, v a speed, k dimensionless. E is output directly in kJ/mm.
Typical applications
Complying with heat-input ranges specified in a welding procedure specification (WPS), and comparing different parameter sets and processes.
Assumptions, limits and common mistakes
Steady arc welding with constant parameters along the whole joint; multi-pass welding, preheat and interpass temperature, and process-specific efficiency scatter are excluded.
Common mistake: Do not confuse the RMS welding current with the peak value in pulsed processes; the formula assumes steady mean values.
Frequently asked questions
What is “Weld heat input (streckenenergie)” used for?
Complying with heat-input ranges specified in a welding procedure specification (WPS), and comparing different parameter sets and processes.
Where do the input values come from?
k is the welding process's thermal efficiency, U the arc voltage, I the welding current and v the welding speed.
What does the result not cover?
Steady arc welding with constant parameters along the whole joint; multi-pass welding, preheat and interpass temperature, and process-specific efficiency scatter are excluded.