Welding is an essential fabrication step during the construction of pipelines using high-strength low-alloy steels. The base metal experiences a rapid thermal excursion in heat-affected zone, resulting modification microstructure and mechanical properties. In particular, coarse-grain zone closest to weld pool significance for integrity pipelines. present work, hardness were quantified from labo...

Usually, tool steels are used in quenched and tempered conditions. Due to the phase transition from austenite martensite volume change during transformation, controlling distortion might be challenging. A newly developed steel focusing on a bainitic structure, even for bigger dimensions, shows lower hardness at ambient temperature than conventional hot working but with dependency. Therefore, se...

X90 pipeline steel was processed with the simulated coarse grain heat affect zone (CGHAZ) thermal cycle with heat input varying from 30 kJ/cm to 60 kJ/cm, the microstructures were investigated by means of optical microscope (OM), scanning electron microscope (SEM), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM), and the impact properties were evaluated fr...

Terms of service of the steels with retained austenite in the microstructure, is severely depended on the stability of austenite during the course of deformation. The present work aims to evaluate the mechanical stability of austenite in nanostructured, carbide free bainitic steels during tensile testing and cold rolling process. To achieve the microstructure with retained austenite, the steel ...

The successive ferrite (α) + pearlite (P) transformations from austenite (γ) have been modeled to predict the intervention of bainite in as-forged medium-carbon manganese steels. The kinetics of the diffusional transformations were calculated based on the classical nucleation-growth theory coupled with the CALPHAD multi-component thermodynamics. The description of growth rate of proeutectoid-α ...

We report an attempt at increasing the thermal stability of nanocrystalline bainite to tempering heat-treatments, by enhancing the silicon concentration of the alloy. Validation experiments have been conducted using synchrotron X-radiation during tempering heat treatment. It is found that the change in alloying successfully stabilises the austenite at elevated temperatures by retarding cementit...