Boiler - Creep Failure

The end of useful service life of the high-temperature components in a boiler (the superheater and reheater tubes and headers, for example) is usually a failure by a creep or stress-rupture mechanism. The root cause may not be elevated temperature, as fuel-ash corrosion or erosion may reduce the wall thickness so that the onset of creep and creep failures occur sooner than expected.


Creep is one of the most serious high temperature damage mechanisms. It involves time-dependent deformation and high temperature creep cracking generally develops in an intercrystalline manner in components of engineering importance that fail over an extended time. These include boiler superheater and other components operating at high temperature, petrochemical furnace and reactor vessel components and gas turbine blades.
While creep failures are expected for superheaters and reheaters operating at design conditions, deviations from these parameters will promote early failures.
Once the condition of the component has been determined by means of metallurgical examination, the expected time to failure must be estimated, primarily in order to schedule future maintenance, inspection activities and to prevents premature catastrophic fracture or rupture.