Fatigue crack growth rates in a pressure vessel steel under various conditions of loading and the environment
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I.
L A R G E steel fabrications are used in the nuclear power industry as the pressure vessel for encapsulation of the reactor primary system. Light water cooled and moderated power reactors contain high temperature, potentially radioactive deionized water circulating through the primary system. This water is shown to be corrosive with respect to the base metal and cladding structural component materials. The structural performance, including the fatigue properties of the vessel, are expected to be influenced by such a corrosive environment. This paper describes some initial experimental work being carried out at the University of the Witwatersrand, South Africa. Once the water treatment facilities and a low temperature corrosion fatigue test loop have been perfected, a high temperature (350 °C)/high pressure (17 MPa) rig will be incorporated for FCGR studies at P.W.R. operating conditions.
II.
Table I. Chemical Analyses Presented as an Average of 25 Determinations
INTRODUCTION
EXPERIMENTAL PROCEDURE
A. Steel Tested The steel tested was an off-cut produced during the manufacture of a P.W.R. nozzle section. Chemical analyses (Table I) and mechanical properties (Table II) showed that the steel conformed to the SA508 C1 3 specification (i.e., a pressure vessel steel). It was also found that there were no through-thickness mechanical property or chemical analysis variations. Figure 1 shows a sketch of the forged nozzle section and the orientations of the test pieces. P.D. HICKS, formerly Graduate Student at The University of The Witwatersrand, South Africa, is Section Leader, Mechanical Behaviour and EnvironmentalEffects, National Institute for Materials Research, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria 0001, SouthAfrica.E P. A. ROBINSONis Professorof CorrosionScience and Engineering,The Universityof The Witwatersrand, South Africa. Manuscript submittedMarch 3, 1986. METALLURGICALTRANSACTIONSA
Element
Average (Wt Pct)
Framatome Specifications (SA508 C1 3)
C 0.16 0.22 max. Mn 1.38 1.12 to 1.58 P 0.013
Data Loading...
