Mechanical properties of a carbide-free bainitic cast steel with dispersed free ferrite

Abstract

A high silicon, medium carbon cast steel was designed and heat-treated in order to develop microstructures composed of carbide-free bainite and small amounts of free ferrite, with the aim of obtaining high strength cast steels with improved ductility. Because of microsegregation, it was observed that ferrite present in partially austenitised samples is mostly present at the highly alloyed zones, creating an interconnected network even for low proportions of this phase. Despite the coarse solidification structure and marked microsegregation in the cast steel, the mechanical properties obtained for both fully bainitic and bainitic-ferritic microstructures largely satisfy the minimum standard requirements for high strength cast steels and are similar to those reported for wrought steels of similar microstructures.