Effects of impurities on environmentally assisted crack growth of solution-annealed austenitic steels in primary water at 325°C

G. F. Li, Y. F. Kaneshima, T. Shoji

Research output: Contribution to specialist publicationArticle

29 Citations (Scopus)

Abstract

Effects of impurities (Si, P, and S) in steel on enuironmentally assisted cracking (EAC) behavior of solution-annealed austenitic steels in pressurized water reactor (PWR) primary water at 325°C were investigated. The basic chemical composition of the steels was 12% Cr-28% Ni, simulating the grain boundary (GB) composition of irradiated Type 304 (UNS S30400) stainless steel. The EAC crack growth behavior of the steels was examined by performing trapezoidal wave cyclic loading testing on precracked specimens. Results showed that Si significantly affected the EAC by promoting intergranular cracking, with only 0.48% Si promoting almost fully intergranular cracking under trapezoidal wave loading; increasing the crack growth rate: and tending to make cracking easier in the near-surface region rather than in the center of specimens. Only transgranular cracking with relatively low crack growth rates took place in the steels witliout Si but doped with S and P, respectively. The stress corrosion cracking (SCC) velocities of the steels during trapezoidal wave cyclic loading were estimated. It also was found that the oxide films formed on Si-doped steels in the water were easier to detach than those on Si-free steels during ultrasonic vibration. Three possible mechanisms were proposed to explain the Si effect on EAC behavior. The present results suggest that a radiation-induced low Cr/high (Ni, Si) GB layer in Type 304 steel can be intrinsically susceptible to intergranular SCC in PWR primary mater.

Original languageEnglish
Pages460-469
Number of pages10
Volume56
No.5
Specialist publicationCorrosion
DOIs
Publication statusPublished - 2000 Jan 1

Keywords

  • Austenitic stainless steel
  • Impurity effect
  • Phosphorus
  • Pressurized water reactor
  • Primary water
  • Silicon
  • Stress corrosion cracking
  • Sulfur

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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