Inputs
How it is calculated
- CET = C + (Mn+Mo)/10 + (Cr+Cu)/20 + Ni/40 (EN 1011-2). CE (IIW) = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15. CEN and Pcm after the formulas published by Dillinger. The composition is entered in % by mass.
- Preheat (EN 1011-2, method B): Tp = 697·CET + 160·tanh(d/35) + 62·HD0.35 + (53·CET − 32)·Q − 328, valid for CET 0.20–0.50 %, d 10–90 mm, HD 1–20 ml/100 g, Q 0.5–4.0 kJ/mm. Outside the range a warning appears.
- Typical hydrogen (Dillinger): MMA 5, MAG/MIG 3, flux-cored 5, SAW 5 ml/100 g. For electrodes, the H5, H10 or H15 symbol in the designation (EN ISO 2560-A) gives the maximum hydrogen.
- The “steel” values are the EN 10025-2 maximum compositions on the cast analysis, for t ≤ 40 mm, as a starting point; use the values from the 3.1 certificate of your own heat. For S235JR and S275JR the silicon has no limit in the sources consulted and stays 0.
- Window diagram: for each combination (heat input, temperature T₀) t8/5 and the preheat are calculated; green means t8/5 falls inside the chosen window and T₀ reaches the preheat required by the formula.
An informative tool, not a WPS. A welding procedure is specified, qualified and approved according to the standards in force, by competent personnel. The calculations here are engineering estimates made with published formulas; they do not replace the manufacturer data sheet, the material certificate, the qualified procedure or the design check.
Frequently asked questions
What is the difference between CE, CET and Pcm?
They all estimate the effect of the alloying elements on hardenability, but with different weights. CE (IIW) has long been used for steels with more carbon, CET is the one EN 1011-2 requires for the preheat formula, and Pcm is meant for low-carbon steels. They are not comparable with each other: each refers to its own limits.
Does a result “below 20 °C” mean no preheating at all?
It means the formula does not require preheating for those data. The plate must still be dry and above freezing, and the qualified procedure remains the one that decides.
Why is above 90 mm or below 10 mm a warning?
The formula was obtained from data in that range. Outside it, it can give unreliable values, so it is shown only with a warning.
Sources and method
The formulas, tables and verification examples come from public sources, listed below. The standards themselves are paid documents and are not reproduced: I cite the formulas and values published by these sources and, where sources differ, I say so.
- Dillinger: Help welding calculation (CET, CE, CEN, Pcm, EN 1011-2 method B, t8/5, F2 and F3 factors)
- EN 10025-2: maximum chemical composition (S235JR, S275JR, S355J2), as published by producers
- TWI: Heat input versus arc energy
- ELGA: Guide to EN ISO 2560-A (symbol tables)