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),...

During the course of our research on the quantitative design of steels [1,2], an exciting discovery was made, in which carbide–free bainite was obtained by transformation at incredibly low temperatures, as low as 125 ◦C [3]. To put this into context, the random jump distance of an iron atom at that temperature is only 10 m over a period of three weeks. The consequence of the low transformation–...

Abstract Nano-bainitic steels have attracted great attention for good wear resistance. In this research, a medium-carbon low-alloyed steel was austempered at low temperature close to its martensite-start various times obtain mixed microstructure of nano-bainite, martensite and retained austenite. The samples were characterised comprehensively by field-emission SEM quantitative XRD. Its two-body...

The effect of austenite grain size on the evolution of the bainite transformation in steels is not yet certain in spite of many investigations.1–7 Barford and Owen1 reported that the reaction rate was accelerated by decreasing the grain size, because of an increase in the number density of grain boundary nucleation sites. Umemoto et al.2 reported similar results and proposed an equation that de...

Shielded metal arc welding and submerged arc welding were used to prepare experimental weld metals with variations in nickel, manganese and carbon contents. The weld metals contained Ni between 6.6 and 10.5 wt. %, Mn between 0.5 and 2.0 wt. % while carbon was varied between 0.03 and 0.11 wt. %. Mechanical properties were found to be sensitive to alloying content. However once the optimum level ...

In the current research, a complex microstructure and crystallographic data were developed through quenching partitioning (Q&P) process to improve tensile properties of commercial pearlitic carbon-silicon steel. Two-stage Q&P process, including full austenitization, at 220 °C, followed by two different temperatures, was applied as-received specimen generate composed tempered martensite, bainite...

An experiment is presented which succeeds for the first time in stimulating the formation of coarse plates of bainite by the coalescence of identically oriented individual platelets. Transformation under the influence of a tensile stress dramatically promotes the formation of the coalesced bainite by increasing the probability of growing parallel platelets in close proximity. Whereas the coarse...

The effects of increasing nickel from 3 to 7 and 9 wt. % were investigated in high strength steel weld metals with 2 wt. % manganese. It was found that nickel additions were positive for strength but negative for impact toughness. Significant segregation of nickel and manganese to interdendritic regions was observed with the two higher nickel contents. In these weld metals a mainly martensitic ...