Kostenoptimierung durch Änderung der Legierungszuschläge für wärmebehandelbare Baustähle

Abstract

Abstract The substitution of expensive alloying elements like Mo and Ni by cheaper ones, e. g. Mn or B-Ti, was studied on the Q&T steel 42CrMo4 and the case-hardening steel 18CrNiMo7-6 based on equal hardenability. The alternative alloying concepts met the requirements for hardenability and mechanical properties in both steel types. The total substitution of Mo by Mn in the Q&T steel caused a loss in low temperature impact toughness. Residual elements (P, As, etc.) seem to promote this kind of temper embrittlement, so for temperature-critical cases the Mo content must be adapted. In the case-hardening steel the substitution of a part of Mo and Ni by Mn or B-Ti resp. lead to a tolerably reduced impact toughness and tooth impact bending force. Nb addition improved the impact toughness. The presented concepts of substitution offer a considerable potential for saving costs for alloy additions.