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Microstructure and properties have been studied for high strength steel weld metals with variations in carbon, manganese and nickel. Based on neural network modelling, experimental welds were made using shielded metal arc welding with manganese at 0.5 or 2.0 wt. % and nickel at 7 or 9 wt. %. Additional welds were made where carbon was varied between 0.03(More)
The relationship between alloying content, microstructure and properties has been studied for high strength steel weld metals with 7 to 9 wt. % nickel. Neural network modelling suggested that manganese reductions lead to large impact toughness increases and that nickel must be added in a controlled manner with respect to manganese in order toincrease impact(More)
Two experimental high strength steel weld metals were produced with 7 wt. % nickel and manganese at 2 or 0.5 wt. %. Neural network predictions that Mn reductions increase toughness were confirmed with impact energy increasing from 32 to 113 J at –40 °C. High resolution microstructural investigations showed that both weld metals contained mainly martensite(More)
The martensite start and bainite start temperatures have been determined in reheated, high strength weld deposits, with each result associated with 95% coincidence limits. This helped define isothermal transformation temperatures where bainite can be obtained without the risk of unintentional transformation to martensite. It has been demonstrated,(More)
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(More)
Neural network predictions suggested that strength of a high strength steel weld metal with 7 wt. % nickel and 0.5 wt. % manganese could be increased significantly at moderate expense to impact toughness by additions of carbon. Based on this, three experimental weld metals were produced with carbon levels between 0.03 and 0.11 wt. %. Mechanical test results(More)
Neural network modelling suggested that the impact strength of high-strength steel weld metals could be increased at moderate expense to yield strength once Ni additions are made in a controlled manner with respect to Mn. Based on these predictions, shielded metal arc welding was used to prepare weld metals with Ni at 7 and 9 wt. % while Mn was at 2.0 or(More)
Coalesced bainite is a coarse constituent recently found to develop along with the classical martensite, lower and upper bainite in steel weld metals. Its crystallography has been characterised using electron backscattering diffraction in combination with field emission gun scanning electron microscopy. It is confirmed that coalesced bainite grains are(More)
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.(More)
Neural network modelling has been applied to search for novel high strength steel weld metal compositions, potentially offering improved tolerance to variations in the weld thermal cycle. An experimental 7 wt% Ni manual metal arc electrode, formulated on these predictions, was used to produce all-weld metals and welds in high strength steel. Mechanical(More)