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Title: Effect of silicon on ultra-low temperature toughness of Nb–Ti microalloyed cryogenic pressure vessel steels

The effect of Si on the ultra-low temperature toughness of Nb–Ti microalloyed cryogenic pressure vessel steels was investigated by electron back-scattered diffraction and transmission electron microscope with energy dispersive spectroscopy. Equiaxed ferrite and bainite were obtained in the tempered steels with small Si additions. Nanosized Nb–Ti carbides (< 10 nm) were formed in the steel containing 0.05% Si, whereas much coarser carbides (> 30 nm) were found in the steel containing 0.47% Si. The ultra-low temperature toughness of the Nb–Ti microalloyed cryogenic pressure vessel steel was remarkably enhanced by the reduction in the Si content, which was attributed to the pre-existing iron carbide formation before the precipitation of nanosized Nb–Ti carbides during tempering. - Highlights: • Nanosized Nb-Ti carbides formed in the tempered steel with smaller Si addition. • Coarser Nb-Ti carbides formed in the tempered steel with more Si addition. • Pre-existing cememtites provide nucleation sites for Nb-Ti carbide precipitation. • Ultra-low temperature toughness was remarkably enhanced by Si content reduction.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4]
  1. Hubei Collaborative Innovation Center for Advanced Steels, International Research Institute for Steel Technology, Wuhan University of Science and Technology, Wuhan 430081 (China)
  2. (China)
  3. (Australia)
  4. Research and Development Center of WISCO, Wuhan 430080 (China)
Publication Date:
OSTI Identifier:
22285083
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 83; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BAINITE; ELECTRON DIFFRACTION; FERRITE; IRON CARBIDES; NANOSTRUCTURES; PRESSURE VESSELS; SILICON; STEELS; TRANSMISSION ELECTRON MICROSCOPY