CALCULATION OF THE HARDENABILITY ON THE B ASIS OF CHEMICAL-COMPOSITION FOR CASE-HARDENING AND QUENCHED AND TEMPERED STEELS

Since 10 years experts of 5 German steel works join in a working group of the German Iron and Steel Institute (VDEh) to continue developing calculation methods for characterising the hardenability of case harde ning and quenched and tempered steels. The cooperative formulae so far derived for different groups of steel are to be verified for their va lidity in the light of new test results. If the outcome is positive, t he intention is to broaden the scope to include new groups of steel. W ithin the context of verifying the existing cooperative formulae for c alculating the hardenability in the end quench test in the light of ne w test results, the findings in respect of the remainder scatters were comparable to those made during the initial evaluation. The validity of these sets of formulae is thereby confirmed. By combining melts of other steel grades into regression universes, it was possible to deriv e new cooperative formulae that satisfy the requirements laid down in SEP 1664 and can be applied to CrNiMo and NiCrMo as well as CrNi and N iCr-alloyed case-hardening steels. First positive results have also be en obtained for MnCrB-alloyed quenched and tempered steels. The workin g group for the ''Calculation of hardenability in the end quench test' ', as part of the materials committee at the VDEh, will continue its e fforts to prepare and introduce further cooperative formulae for, amon g others, the 16/18MnCrB5 steel, CrV-alloyed quenched and tempered ste els, and ferritic-pearlitic engineering steels for precipitation harde ning.