The Influence of Strain Rate and Strain Intensity on Retained Austenite Content in Structure of Steel with TRIP Effect

Abstract

TRIP (transformation induced plasticity) steels are low and medium-carbon steels containing soft ferritic groundmass responsible for low yield point and phases of hard particles such as martensite and/or bainite, which ensure high values of tensile strength. The most important content in structure of TRIP steel is occupied by a non-transformation retained austenite. The advantageous properties of these steels are obtained as a result of martensite transformation generated by plastic deformation process. The retained austenite induces increase of steel plasticity till the moment when by the impact of plastic deformation will undergo deformation in martensite, which results in the increase of steel mechanical properties. The speed of transformation of retained austenite in martensite is highly dependent on strain magnitude and strain rate magnitude. The paper presents the research of strain rate and intensity on retained austenite content ensuring TRIP effect in structure of low carbon steel (0.29%C). Finite element analysis for different strain rate and strain degree values in upsetting test was performed by means of software FORGE 3D. The practical analysis obtained from simulation results was realized by using metallurgical processes simulator Gleeble 3800.