CALCULATION OF THE HARDENABILITY ON THE BASIS 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 hardening and quenched and tempered steels. The cooperative formulae so far derived for different groups of steel are to be verified for their validity in the light of new test results. If the outcome is positive, the intention is to broaden the scope to include new groups of steel. Within the context of verifying the existing cooperative formulae for calculating the hardenability in the end quench test in the light of new 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 derive 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 NiCr-alloyed case-hardening steels. First positive results have also been obtained for MnCrB-alloyed quenched and tempered steels. The working group for the ''Calculation of hardenability in the end quench test'', as part of the materials committee at the VDEh, will continue its efforts to prepare and introduce further cooperative formulae for, among others, the 16/18MnCrB5 steel, CrV-alloyed quenched and tempered steels, and ferritic-pearlitic engineering steels for precipitation hardening.