Environmental Engineering Reference
In-Depth Information
P f
5.55 Dependence of the probability of failure on γ .
P f
￿ ￿ ￿ ￿ ￿
5.56 Dependence of the probability of failure on a max .
The mechanical properties of steels 08Kh18N12T and of welds in these
steels after prolonged operation in the pipeline of the reactors VVER-440
were determined in Ref. 98-103, 9, etc.
The test results obtained for samples cut from metal of MCO DN-500
after 100 000 hours of operation are presented in Table 5.12 and Fig. 5.60.
The results of tests of the same metal after austenitising and tempering
as well as the certificate data are also included. The certificate data and
test results after long-term service as well as after long-term servive and
heat treatment are presented. The comparison showed that the differences
of values of mechanical properties ( R m , R p0.2 , A 5 , Z ) are within the natural
variability of the mechanical properties and the effect of errors in the tests.
Further studies of the effect of operational impacts (150 000 hours of
operation) showed no significant changes in the mechanical properties of
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