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EFFECTOF ENVIRONMENTONCREEP-
RUPTURE PROPERTIES
OF HASTELLOY 6
C. R. Kennedy'
Revised design data obtained from creep tests
of solution-annealed Hastelloy B sheet stock in
various environments at 1300, 1500, and 1650°F
ore summarized in Figs, 3.5.1, 3.5.2, and 3.5.3.
The times to 0.5, 1, 2, 5, and 10% total strain at
each temperature in the various environments are
the same, and for stresses for which the rupture
life is more than 300 hr the effect of environment
is shown to be negligible. The creep curves
obtained at 1500OF in air and in argon, shown in
Fig, 3.5.4, appear to indicate that the better
performance in air than in the other environments
at stresses for which the rupture life is less than
'On assignment from Pratt 8, Whitney Aircraft.
3.5. MECHANICAL PROPERTIES STUDIES
D. A. Douglas
(0 20 50 400 200
TIME (hr)
PERIOD ENDING JUNE 16, 1956
300 hr is caused by the ability of air to strengthen
Hastelloy B during third-stage creep. For rupture
lives longer than 300 hr there is considerably
less third-stage creep because of the aging
characteristics of the alloy, and, as seen in
Figs. 3.5.1, 35.2, and 3.5.3, the effect of environ-
ment diminishes. Design curves produced from
limited data for solution-annealed Hastelloy B
sheet tested at 1800OF in argon and in the fuel
mixture (No. 30) NaF-ZrF,-UF, (50-46-4 mole %)
are shown in Fig. 3.5.5. At 180OOF Hastelloy B
does not age perceptibly and the amount of third-
stage creep is great in tests at all stress levels.
Thus the fuel dxture strengthens the alloy at all
stress levels, Of the environments tested, only
those which are "surface active" (produce a
thin, tightly adherent film on the surface of the
metal) affect the creep properties of the metal.
It can be seen from Figs. 3.5.1, 3.5.2, 3.5.3,
and 3.5.5 that, of the environments tested, only
500 tow 2
5FeRu
ORNL-LR-DWG 14729
D 5000 10,Ooo
Fig. 3.5.1. Design Curves for Hastelloy B Sheet Solution Annealed at 210OOF for 2 hr and Tested
in Argon and in the Fuel Mixture (No. 30) NaF-ZrF,-UF, (50-46-4 mole 56) at 1300OF.
2 01