The carbon concentration trapped in films of austenite between parallel platelets of bainite is often found to be much larger than that in the larger blocks of austenite between sheaves of bainite. The effect of this non-uniform distribution of carbon on the overall transformation kinetics of bainite is examined theoretically. It is found that the trapping of carbon in the films of austenite ac...

The mechanism of the bainite transformation in carbon containing steels was discussed after presenting our recent experimental results; (1) the bainite transformation has its own C-curve, (2) incomplete phenomenon is a general feature of the bainite transformation, (3) bainitic fenite grows to a limited size, and (4) bainitic ferrite is highly supersaturated with respect to carbon. It was exami...

Abstract This research paper mainly studied the microstructure and hardness of weld bead welding heat affected zone ultrafine grain steel after CO 2 gas-shielded welding. After normalizing quenching treatment, changes in welded joints were studied. These experimental results showed that joint was dendritic. The a mixed structure proeutectoid ferrite, side plate bainite, pearlite. overheated HAZ...

The strength of mixed microstructures of bainite and martensite can peak at an intermediate volume fraction of martensite has been published by recently experimental studies. A quantitative interpretation of these observations is achieved by modelling the mechanical properties of mixed microstructures of bainite and martensite. The peak in the curve of the strength as a function of the volume f...

The development of ultrafine bainitic structure in AISI 431 stainless steel was the goal of this study. For this purpose, the AISI 431 specimens were austenitized at 1100 °C for 60 min followed by low-temperature austempering treatment at different temperatures and times. Austempered samples were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (X...

: Consistent with the wishes of the Conference Organisers, the basic theory of the bainite reaction including the crystallographic, thermodynamic and kinetic framework is described, together with the development of fine bainite and its properties.

A coarse grained constituent recently discovered in high strength steel weld metals – Coalesced Bainite – was investigated with a serial section procedure for three-dimensional (3D) analysis using Focused Ion Beam (FIB) milling. Image planes of a coalesced bainite grain, 0.4 μm apart were acquired using the FIB. The data collected was then used to create a 3D model of the coalesced bainite grai...

An experimental high strength steel weld metal containing 7 wt. % nickel and 2 wt. % manganese was found to have a complex microstructure. Employing high resolution characterisation techniques the microstructure consisted primarily of a mixture of martensite, upper bainite and a novel constituent with large grain size that contained plate-like precipitates. This constituent was characterised to...

The possibility of producing bainite at low temperatures by suppressing transformation using substitutional solutes has been investigated, as an alternative to using large carbon concentrations to achieve the same purpose. It is found that although transformation temperatures can indeed be suppressed in this way, the difference between the bainite and martensite start temperatures diminishes. T...

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),...