Study of evolution of microstructure and mechanical properties of high silicon austempered steel

Since some years now, one of the main objectives of the metallurgical researches, in particular regarding ferrous alloys, has been the development of materials with high resistance characteristics, guaranteeing reduced weights and costs for the structures made with them. Currently steels as, AHS and TRIP, are very interesting. They combine several microstructural constituents, bainite, martensite and residual austenite, which during deformation transforms into martensite. Martensitic transformation induced by strains increases ductility and mechanical strength, delaying fracture and allowing thickness reductions and therefore components weight and costs. The aim of this study is to study a new high silicon steel composition with the possibility of its use for new structural applications. After the treatments, the samples were characterized by microstructural investigation with an optical and electron microscope and by diffraction X-ray. Hardness and tensile tests were performed to evaluate the mechanical characteristics. The material has a mechanical strength of 1720 MPa with an elongation of 22% and TRIP effect.