The successive ferrite (α) + pearlite (P) transformations from austenite (γ) have been modeled to predict the intervention of bainite in as-forged medium-carbon manganese steels. The kinetics of the diffusional transformations were calculated based on the classical nucleation-growth theory coupled with the CALPHAD multi-component thermodynamics. The description of growth rate of proeutectoid-α ...

Knowledge of carbon content in retained austenite (RA) with different neighbouring phases is essential to understand the chemical stability of RA, which is useful for microstructure tuning of transformation-induced plasticity (TRIP) steels. The present study investigates different morphologies and chemical compositions of RA by correlating electron backscattering diffraction, transmission elect...

In this study, two CCCT diagrams are drawn to be compared with a CCT diagram. The CCCT diagrams represent continuous cooling transformations in stress assisted state. The increased Md and Bd temperatures of CCCT diagrams were also compared with those of the CCT diagrams and the cause was investigated from both thermodynamic and metallurgical viewpoints. Thermodynamic examinations revealed that ...

High-carbon steels which are transformed into extremely fine bainite plates embedded in a matrix of carbon-enriched austenite have recently been developed, and have found commercial application in the manufacture of engineering components. However, because of the large carbon concentration, they cannot be welded and this limits the scope for their exploitation. A method is reported here by whic...

There has been a great deal of work on the formation of hard white-etching regions in conventional bearing steels such as 1C-1.5Cr wt% when subjected repeatedly to rolling contact stresses. The regions are a consequence of localised mechanical attrition across microcrack faces and mixing, which refine the local structure and force cementite to dissolve. This white-etching matter is often associ...

In this work, three low-carbon bainitic steels, with different Mo contents, were designed to investigate the effects of Mo addition on microstructure and mechanical properties. Two-step cooling, i.e., initial accelerated cooling and subsequent slow cooling, was used to obtain the desired bainite microstructure. The results show that the product of strength and elongation first increases and the...

• Limited effect of temerping at 400 and 500°C on non-ausformed crabide-free bainite. Dilatometric contraction occurred for ausformed bainite sample due to cementite precipitation. Carbon diffusion was enhanced by dislocations generated during ausforming processes. The influence tempering 500 °C two bainitic ferrite microstructures obtained via pure isothermal transformation followed the studie...