Exceeding the recommended service temperature of specific heat-resistant alloys can accelerate the pace of property deterioration, leading to premature failure.
The main strengthening mechanism of conventional heat-resistant alloys (HRAs) in operation during the steady-state creep process is carbide dispersion strengthening. To better understand alloy behavior at operating temperatures, it is helpful to look at a carbide-dispersion model as a function of temperature and time. Increases in temperature and/or long exposure to high temperature affect the growth and morphology of carbide (and sometimes nitride) precipitates in these alloys. Precipitation of secondary carbides does not start until a temperature of around 1100 F (595 C), but carbide morphology is greatly affected by subsequent increases in temperature.