Effect of transformation temperature on microstructure and mechanical properties of bainite

الملخص EN

Fully bainitic microstructure can be obtained by isothermal transformation at temperatures within the range of bainite transformation.

Both transformation temperature and time determine the phase fraction, the scale of the resultant microstructure and the carbone content of the retained austenite, which in turn determine the mechanical properties.

In this study, the thermomechanical simulator was used to obtained the fully bainitic microstructure for the high carbon alloy steel (0.78%C) at a different bainite transformation temperatures (200 to 350°C) in order to study the effect of the isothermal transformation temperature on the resultant mechanical properties.

It has been concluded from the detailed analysis of the microstructure, the dilatometric data and the mechanical properties (hardness and tensile properties) that finer bainite and less retained austenite phase fraction can be obtained by transformation at lower temperatures, and that leads to exceptional mechanical properties (Hardness ≈ 660 HV, and Tensile strength ≈ 2 Gpa).