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Silicon-Bearing High-Chromium Heat-Resistant Steels

  • Wei YanEmail author
  • Wei Wang
  • Yiyin Shan
  • Ke Yang
  • Wei Sha
Chapter
Part of the Engineering Materials book series (ENG.MAT.)

Abstract

The addition of silicon in the steel can increase the fraction of the δ ferrite. δ ferrite reduces the strength but does not decrease the toughness. The matrix continuity is interrupted by the stripe-like δ ferrite distributed along the rolling direction, which causes delamination fracture upon impact. However, the δ ferrite can be eliminated by increasing the carbon content to 0.25 %. Carbides in the steel are dissolved greatly above 980 °C. Additional expansion occurs on the dilatometry curve. When normalised at 1030–1100 °C, large-size Cr23C6 carbides containing silicon precipitate along the grain boundaries. Tensile properties of the steel increases with normalising temperature below 1030 °C and remains almost unchanged at higher normalising temperatures. The toughness of the steel decreases with normalising temperature. The large-size chain-like Cr23C6 carbides along grain boundaries are the key factor to reduce the toughness. The toughness of the steel decreases greatly when tempered at 450–600 °C, the hardness reaches a maximum and the steel exhibits morphology of intergranular plus quasi-cleavage fracture. The grain boundary weakening caused by the precipitation of chain-like carbides along grain boundaries and the secondary hardening produced by fine dispersed carbides are the main causes for the temper embrittlement.

Keywords

Impact Energy Impact Toughness Intergranular Fracture Carbide Precipitation Impact Fracture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Wei Yan
    • 1
    Email author
  • Wei Wang
    • 1
  • Yiyin Shan
    • 1
  • Ke Yang
    • 1
  • Wei Sha
    • 2
  1. 1.Institute of Metal Research, Chinese Academy of SciencesShenyangChina
  2. 2.Queen’s University BelfastBelfastUK

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