The influence of chemical composition and temper heat-treatment on strength and impact toughness in Ni-Cr-Mo-V steels

Yomei Yoshioka, Hiromichi Itou, Yasuhiko Tanaka, Yasumi Ikeda

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

To meet the requirements for optimum utilization of power station sites and economic realization of coal fired thermal units, tandem compound 60 Hz 1000 MW large thermal units were developed. One of the most critical items was development of a large-size high strength generator rotor forging with comparable toughness to the conventional rotor forging. Based on the investigation results of existing rotor forging, chemistry optimization was conducted within the specification of conventional turbine generator and low pressure rotor forging by using laboratory heat materials and 0.28%C-0.25%Mn-4%Ni-1.75%Cr-0.4%Mo-0.12%V high purity steel was selected for the candidate material. Double tempering heat treatment of 550°C and 580°C was also developed for increasing the yielding ratio of 0.02% yielding stress to tensile strength to meet the requirements of mechanical properties. According to those laboratory studies, one trial rotor forging with the same diameter as production ones was successfully produced.

Original languageEnglish
Pages (from-to)705-710
Number of pages6
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume89
Issue number6
DOIs
Publication statusPublished - 2003 Jun
Externally publishedYes

Keywords

  • Double temper
  • Heat treatment
  • Ni-Cr-Mo-V steel
  • Residual γ
  • Rotor forging
  • Toughness
  • Yield ratio

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

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