Features of Titanium Carbide Precipitation in Low-Carbon High-Strength Steels Microalloyed with Titanium and Molybdenum

Resumo

Theoretical and experimental study is carried out to establish features of all types of excessive phase precipitation in low-carbon steels microalloyed with titanium and molybdenum. It is established that the main type of precipitates controlling grain boundary and precipitation hardening mechanisms is FCCcarbide based on TiC. The optimum thermal deformation treatment regime is established providing simultaneously effective grain refi nement of steel structure and the formation of a system of nanosize carbide precipitates that control strengthening by a precipitation hardening mechanism. On the basis of the results obtained, chemical composition and heat-treatment regime are proposed for producing low-carbon TiM–Mo microalloyed steels with a ferritic microstructure and set of mechanical (tensile strength more than 850 MPa) and other service properties.