Abstract:
In power plant heat tube is the main
component where the water is changed to
high-pressure steam, it operates under
corrosive and high temperature
environment. Corrosive environment and
cyclic temperature fluctuation cause fatigue
on boiler heater tube, and which degrade
life of the component. This paper presents
corrosion rate by volumetric pit growth,
crack initiation and crack propagation of
boiler heat tube for power plant under
cyclic thermal load. 8.72Cr-0.9Mo steel is
one of the steel type which mostly used
nowadays as boiler heat tube. Volumetric
pit growth rate approach used for crack
initiation and energy release rate approach
(J-integral) used to find crack propagation
phenomenon. Temperature is taken in the
interval of 25 - , and it has a
significant effect on rate of chemical
reaction (corrosion rate) and material
properties. The results show 906Mpa and
895Mpa thermal stress induced at crack tip
at from analytical and FEM
respectively. And also energy release rate
results are ⁄ ⁄
from analytical and FEM respectively.
From the result, material reach fatigue limit
in the range of low cycle fatigue having the
value less than
cycles. The existence of
corrosion reduces crack initiation cycles
since crack initiation is speed up by the
presence of corrosion.
