Topic
Microalloyed steel
About: Microalloyed steel is a research topic. Over the lifetime, 2183 publications have been published within this topic receiving 33586 citations.
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TL;DR: In this paper, the formation mechanism of tight oxide scale on microalloyed steel was investigated at temperatures of 550-850°C in dry air, and microstructural characterisations reveal that the spallation of oxide scale dominates at the centre of coarse grains on the oxidation initiation.
30 citations
TL;DR: In this paper, the micro mechanical properties, stability and 3D morphology of intragranular ferrite was studied in a low carbon microalloyed steel utilizing nano indentation, three-dimensional reconstruction techniques along with LEO1 450 scanning electronic microscopy.
Abstract: The micro mechanical properties, stability and three-dimensional (3D) morphology of intragranular ferrite was studied in a low carbon microalloyed steel utilizing nano indentation, three-dimensional reconstruction techniques along with LEO1 450 scanning electronic microscopy. The mixed microstructures of intragranular ferrite, granular bainite and lath or plate-like bainite was obtained in a Nb–Ti microalloyed steel, which was water cooled immediately after relaxation for a fixed time as hot deformation ended. The elastic modulus and hardness increased in the sequence of intragranular ferrite, granular bainite and lath or plate-like bainite by approximately 15 GPa and 0.6 GPa, respectively. On the contrary, the tempering treatment of the specimens showed that the stability of the mixed microstructures decreased in the sequence of intragranular ferrite, granular bainite and lath or plate-like bainite. The results of stability, elastic modulus and hardness indicated that intragranular ferrite was formed prior to bainite transformation. The intragranular ferrite thus effectively sectioned the prior austenite into many small zones and thus the bainite transformed at lower temperatures was restricted in the small zones. It is likely that the formation of lath or plate-like intragranular ferrite prior to bainite transformation played an important role in the refinement of mixed microstructures.
30 citations
15 Aug 2005-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the authors deal with the strain-induced dynamic transformation of ferrite, which results in the formation of ultrafine ferrite grains (∼1μm) thereby enhancing the mechanical properties compared to the ordinary hot rolled products without the necessity of implementing an extremely high strain accumulation.
Abstract: In recent years, several studies on grain refinement of ferrite have been conducted by different methods (equal channel angular pressing (ECAP), high pressure torsion (HPT), accumulative roll bonding (ARB)) in order to optimize the relationship between mechanical properties and microstructure of steels. The present work deals with the strain-induced dynamic transformation of ferrite. Samples of low C–Mn and Nb–Ti microalloyed steels were intensively deformed in warm torsion. This resulted in the formation of ultrafine ferrite grains (∼1 μm) thereby enhancing the mechanical properties compared to the ordinary hot rolled products without the necessity of implementing an extremely high strain accumulation. The following annealing has resulted in recrystallization and growth of ferrite grains accompanied by a homogenization of the final microstructure and a decrease in hardness. With increase in annealing time the volume fraction of martensite/austenite (MA) constituent increased. The results have shown that the effect of steel chemistry was insignificant in comparison with the effect of thermomechanical processing parameters.
30 citations
TL;DR: In this article, a generalised regression neural network was developed to predict the impact energy as a function of experimental conditions, which was used for the production of the API X65 steel.
30 citations
TL;DR: In this article, the critical cleavage stress values and carbide sizes obtained in a recent work by Lee et al. were recalculated using 2D and 3D finite element simulations and new constitutive law, instead of small scale yielding assumption and likely improper choice for the behavior of SA 508 steel.
29 citations