Ein hochfester Stahl mit guten Zähigkeitseigenschaften : Entwicklung eines neuen Stahles zur Gewichts- und Kostenreduzierung im Automobilbau. Diskussion

The purpose of this joint project was to develop a steel which achieves high strength and at the same time good toughness properties after quenching from forging heat without any further heat treatment. The strength values (1100 to 1200 MPa) in combination with the toughness (A = 12-14 %, Z = 60-65 %, A vRt = 50-60 J) determined for laboratory melts were verified at series production components from an industrial melt. Component fatigue tests showed that the fatigue strength increased by approx. 50 %. The new steel grade has many advantages over hardening and tempering steels in a comparable range, namely the saving of heat treatment costs, process operations, installations and environmental costs. The advantages over AFP steels lie in the higher mechanical properties which lead to weight-reduced components.