Constitution diagram
to Schaeffler
About the method
The Schaeffler diagram (1949) assigns a expected microstructure to a chromium and nickel equivalent: austenite, ferrite, martensite or their mixtures. It is the oldest and coarsest of the three, but covers the widest range and is the only one to show the risk of martensite.
Chromium equivalent = Cr + Mo + 1.50·Si + 0.50·Nb + 2·Ti
Nickel equivalent = Ni + 30·C + 0.50·Mn
The titanium term (2·Ti) in the chromium equivalent is an extension of the original Schaeffler formula. The former calculator carried it and stated it on the axis; that remains.
About dilution
Welding two base materials with filler produces a weld metal whose composition lies between them. The degree of dilution states what share comes from the melted base material. The point travels along the line from the midpoint of the two base materials to the pure weld metal.
What has changed against the previous diagram
- If a point lay exactly on the first iso-line, the page used to end in a server error and showed no diagram at all.
- An empty input field made the diagram disappear. It now counts as zero.
- Outside the line fan no value is invented any more. Previously the measurement was taken against the extended lines.
- All labels are translated. The English page used to read “Ferrit!” and “1,5%Si” with a German comma.
- The diagram is now vector graphics: crisp on every screen, legible on a phone, and the text can be selected.
Schaeffler 1949 · DeLong 1974 · WRC-1992