High resolution synchrotron X–ray diffraction has been used to conduct in situ studies of the temporal evolution of phases during the isothermal growth of bainite. Two populations of austenitic material were identified: one corresponding to the initial austenite, the other to the carbon–enriched austenite associated with the bainitic ferrite. The observed lattice parameters and the asymmetry of...

color metallography is a useful method for characterizing microstructures of steels with multiple phases. in this paper, application of three different color etching techniques for a bainitic-martensitic steel is reported. comparisons between the results showed that 10% na2s2o5 aqueous solution was the best etchant for distinguishing martensite, bainite and ferrite phases. the obtained microgra...

An artificial neural network (ANN) model was designed to predict the tensile properties in high-strength, low-carbon bainitic steels with a focus on fraction of constituents such as PF (polygonal ferrite), AF (acicular GB (granular bainite), and BF (bainitic ferrite). The input parameters were constituents, while output composed yield strength, yield-to-tensile ratio, uniform elongation. ANN ex...

There is a novel range of steels under development, based on bainite forming at exceptionally low temperatures. The advantage of suppressing the transformation temperature is that incredibly fine platelets of bainitic ferrite are generated which are only 20–40 nm in thickness. This makes the steel strong and in combination with the austenite that is retained, gives a useful range of properties ...

In this work, a weld metal in K65 pipeline steel pipe has been processed through self-designed post-weld heat treatments including reheating and tempering associated with hot bending. The microstructures and the corresponding toughness and microhardness of the weld metal subjected to the post-weld heat treatments have been investigated. Results show that with the increase in reheating temperatu...

In recent years, there has been a growing interest in steels of multi-phase structures, composed of a ferritic matrix, in which islets occur, that contain bainite-B, martensite-M and the untransformed austenite-A 1-9 . The multi-phase structure of steel with untransformed austenite promotes the increase of plasticity induced by the phase transformation – the TRIP effect 3-4, 6-8 . In steels con...

The microstructural evolution of and simultaneous dimensional changes in high-carbon SAE 52100 bearing steel were monitored continuously during austempering for 120 min at selected temperatures the range 210 °C-270 °C, also its subsequent tempering to 340 °C an additional min, via high-energy X-ray diffraction real time in-situ dilatometry. austenite-to-bainitic ferrite transformation induces l...