life-span-decrease-by-overtemperatureCreep life span [h]Static tensile stress [MN/m2]100010010100100010000Every instance of overtemp-erature takes a considerabletoll on the life span of thehot parts. At the applicationlimit, a temperature increaseof 15°C cuts the life span inhalf!!123L/2L1015°C1030°CTurbine rotor bladeCreep-criticalcross-section= const.T1T2T3T1>T2 (= T1-15°C) >T3 (=T1- 30°C)TimeCreep strainL1L2 (= 2 L1)L3 (= 2 L2 = 4 L1)T = const.123TimeCreep strainL1L2 L3The creep strain to fracture of the creep curves under equal loads and different temperatures, as well asthose under different loads and equal temperatures, are located on the same curve. 1 > 2 > 3 "A rule of thumb"15°Cincrease in temperatureresults in a reduction of life span by half