Schaeffler diagram

Formulas

Cr_eq = Cr + Mo + 1.5 · Si + 0.5 · Nb

Ni_eq = Ni + 30 · C + 0.5 · Mn

Calculation rules

Cr and Ni contents are required. Other elements left empty are taken as 0% (with a notice).
Simplified diagram: four boundary lines divide the field Cr_eq 0–40%, Ni_eq 0–30% into seven regions: A, A + M, M, A + F, A + F + M, F + M, F.
The result shows the region where the point lies. It does not give the ferrite content (%) or ferrite number and does not account for nitrogen or cooling conditions; treat points close to boundary lines as indicative.
Points outside the diagram are drawn on its edge.
Rounding: 2 decimal places.

Results are for guidance only, with no guarantee of correctness – check them against the current edition of the standard. They do not replace a WPS or the decision of the welding coordinator. Full description in the methodology