The Schaeffler diagram has been developed for the assessment of welded connections of alloyed, especially stainless steels. This made it possible to make statements about the expected mixed structure when connecting very different steels.
Based on the cast steel, the Schaeffler diagram allows an initial estimate of the structural condition of stainless steels. In the chrome equivalent, the ferrite formers and in the nickel equivalent, the austenite formers are taken into account according to the effect on the structural condition.
The phase fields indicate which structure can be generated depending on the chemical composition, i.e. martensite, austenite and ferrite. In addition, the groups of stainless steels (ferritic, martensitic, austenitic stainless steels and duplex steels (austenite and ferrite) can be determined.