Lista wynalazków

Multi-phase steel for the production of premium rails characterized by high wear and fatigue resistance

autorzy: dr hab. inż. Krzysztof Radwański, prof. dr hab. Roman Kuziak

The present invention relates to carbide-free multi-phase steel, composed essentially of TRIP assisted bainite. Multi-phase steel according to the invention is preferably used for the production of flanged Vignole rails of enhanced durability in service, and specifically, of enhanced resistance to wear and contact-fatigue defects initiation and growth, compared to the air cooled rails of pearlitic steels after hot rolling. The desired properties of the rails are achieved during cooling in still air after rolling without the necessity of performing isothermal treatment – so called bainitization. Retained austenite is in the amount greater than 12% by volume fraction. This feature of rails is achieved by properly alloying of medium carbon steel and adding Ti in the amount giving rise to the precipitation strengthening of bainitic ferrite by TiC nano-particles. Moreover, the main chemical steel composition includes 0.28%C, 1.1%Si, 2.5%(Mn+Cr). The mechanical properties of rails made of this steel are as follows: Rp0.2>700 MPa, Rm>1200MPa, A10>20%, 400-450HB.