Creep deformation characterization of heat resistant steel by stress change test

Hiroyuki Hayakawa, Satoshi Nakashima, Junichi Kusumoto, Akihiro Kanaya, Hideharu Nakashima

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

To evaluate the creep deformation mechanism of heat resistant steel, stress change tests were conducted during creep tests for Modified 9Cr-1Mo Steel and 2.25Cr-1Mo Steel. In this study it was confirmed that the dislocation behavior during the creep tests was in viscous manner because of no instantaneous plastic strain observed at stress increments. Transient backward creep behavior was observed after stress reduction for these steels in this work. Mobilities of dislocation were evaluated by observed backward creep behavior after stress reductions. Internal stresses were evaluated by the changes of creep rate in stress increments. And mobile dislocation densities were evaluated with the estimated mobilities of dislocation and the changes of creep rate in stress increments. It was found that the variation of evaluated mobile dislocation densities during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of these steels in this work. The mobilities of dislocation showed a good correlation with 1/T and related with solute amount of Mo that is a solution hardening element.

Original languageEnglish
Pages (from-to)556-562
Number of pages7
JournalInternational Journal of Pressure Vessels and Piping
Volume86
Issue number9
DOIs
Publication statusPublished - Sep 2009

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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