The influence of isothermal treatment prior to the initial quenching step Q&P process was investigated in 0.26C – 4.15Mn 1.39Si steel. Compared microstructure processed steel: a mixture martensite and retained austenite, subjected before (BQ&P) consists bainitic ferrite, austenite. Formation ferrite during refined austenite grain size made filmy morphology prevalent final microstructure. Beside...

There is a novel steel invented in which the structure consists of extremely fine platelets of bainitic ferrite dispersed in a matrix of carbon enriched retained austenite. The resulting large density of interfaces makes the alloy very strong in its transformed condition. The authors report the first fatigue tests on this system, by measuring the life of parallel gauged samples tested using cyc...

The tempering of two–phase mixtures of bainitic ferrite and carbon–enriched retained austenite has been investigated in an effort to separate the reactions that occur at elevated temperatures from any transformation during cooling to ambient conditions. It is demonstrated using synchrotron X–radiation measurements, that the residue of austenite left at the tempering temperature partly decompose...

Ti-containing steel weld metals with boron addition contents of 0-85 ppm were prepared, and their microstructural characteristics as well the impact toughness investigated. The results show that in these microstructures, compared to metal without boron, 22-39 a remarkable increase amount acicular ferrite at expense grain boundary ferrite, idiomorphic side-plate ferrite. However, further content...

In-situ time-resolved X-ray diffraction technique with synchrotron radiation was used to track austenite decomposition in steels. Measurements from a Fe-C-Si-Mn steel indicate two lattice parameters in the austenite, possibly due to the development of carbon-rich and carbon-poor austenite prior to transformation. The lattice parameter became uniform with the progress of transformation and the f...

the influence of aluminium on the microstructure of austempered ductile cast iron (adi) has been studied. anumber of irons of different compositions have been made by green sand casting and gravity die casting ofappropriate design to provide the experimental materials. austenitising was carried out at different temperaturesand holding times for a variety of experimental irons to achieve suffici...

The influence of bainite morphology on the impact toughness behaviour of a continuously cooled cementite free low carbon C-Mn-B type of steel has been examined. Different bainite morphologies were obtained by cooling from the austenite regime to ambient temperature with different cooling rates. The resulting microstructures have been quantitatively analysed using light optical microscopy (LOM),...

with careful design, mixed microstructures consisting of fine plates of upper bainitic ferrite separated by thinfilms of stable retained austenite have exhibited impressive combinations of strength and toughness in highsiliconbainitic steels. the silicon suppresses the precipitation of brittle cementite leading to an improvement intoughness. the essential principles governing the optimisation o...