Improvement of a Set of Steel Properties Due to Forming Phase Precipitates During Hot Deformation Combined with Quenching

Abstract

The effect of nano-sized carbide and carbonitride precipitate formation during hot deformation combined with quenching on steel strength is studied. Results obtained for a complexly alloyed laboratory melted model steel indicate that with metal cooling rates 22–25°C/sec, adequate for obtaining a martensitic structure, there is formation of nano-sized carbide and carbonitride precipitates providing additional steel hardening. This makes it possible to achieve good ultimate strength (2130 MPa), yield strength (1850 MPa) and relative elongation (not less than 11%) indices. According to the results of studying three specially selected different melts of industrial steels it has been established that the formation of nanosize carbonitrides and other types of precipitates stimulates the implementation of additional hardening mechanisms, resulting in a significant increase (up to 250–300 MPa or more) in strength properties.