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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15 Sep 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the relationship between microstructure and impact toughness was investigated for niobium-microalloyed steels with similar yield strength, and it was shown that toughness is strongly influenced by mean intercept length of polygonal ferrite and pearlite colony.
Abstract: The relationship between microstructure and impact toughness was investigated for niobium-microalloyed steels with similar yield strength. The nominal steel composition was similar and any variation in processing history was unintentional. The general microstructure of the investigated steel was similar and consisted of 85% polygonal ferrite and 15% pearlite. Despite these similarities, they exhibited variation in toughness and were classified as high- and low-toughness steels. Detailed microstructural investigation including stereological analysis and electron microscopy implied that toughness is strongly influenced by mean intercept length of polygonal ferrite and pearlite colony, and their distribution, interlamellar spacing, and degenerated pearlite.
21 citations
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TL;DR: A semi-empirical model has been proposed for prediction of microstructural development during austenite decomposition of the steel and the resultant hardness as mentioned in this paper, which consists of 8 sub-models including ferrite transformation start temperature, ferrite growth, pearlite start temperature and hardness.
21 citations
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TL;DR: In this article, phase field modelling is used to simulate austenite grain growth in the heat affected zone (HAZ) of an X80 linepipe steel, where grain boundary mobilities are introduced that are consistent with strong pinning at lower temperatures and weak pinning in higher temperatures.
Abstract: Phase field modelling is used to simulate austenite grain growth in the heat affected zone (HAZ) of an X80 linepipe steel The HAZ experiences a very steep temperature gradient during welding which restricts grain growth In addition to this phenomenon known as thermal pinning, austenite grain growth is affected by pinning due to precipitates and their potential dissolution Grain growth has first been simulated for bulk samples subjected to rapid heating conditions to replicate thermal cycles at various positions in the HAZ Effective grain boundary mobilities are introduced that are consistent with strong pinning at lower temperatures and weak pinning at higher temperatures These two temperature regimes are separated by the estimated dissolution temperature of fine NbC precipitates These mobility relationships are then used to predict austenite grain growth in the HAZ using typical time–temperature profiles
20 citations
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TL;DR: In this article, a multiphase (ferrite-bainite-martensite) microstructure was developed in an automotive grade medium carbon microalloyed steel 38MnSiVS5 through a two-step cooling and annealing process following controlled rolling.
20 citations
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TL;DR: In this article, the effect of Nb on the microstructure evolution of low carbon Mn-series air cooled bainitic steels has been studied by using thermomechanical simulation machine, SEM, and TEM observation.
Abstract: The effect of Nb on the microstructure evolution of low-carbon Mn-series air cooled bainitic steels has been studied by using thermomechanical simulation machine, SEM, and TEM observation. The results show that the amount of ferrites is relatively higher in the steel without Nb than that of Nb-bearing steel under same deformation conditions, and the ferrites in Nb-bearing steel are more finer. The mechanical properties of the Nb-bearing steel are higher than those of the steel without Nb at the same finishing rolling temperature (FRT), and the toughness of the Nb-bearing steel is about 100 J higher than that of the steel without Nb at the finishing rolling temperature 750 °C. The toughness of Nb microalloyed steel will be improved more effectively than that of the steel without Nb with the decrease of FRT.
20 citations