The material lifetime is depending on the work condition.lncoloy 800 has an allowable stress 88,9 MPa at 593°C, but at 982"Cit decrease to 3,4 Mpa. Larson-Miller explains that the lifetime of this alloy was influenced by these both parameters, whi.:hare temperature and working stress. In certain temperature the increase of the working temperature equivalent t050°C, willdecrease the alloy lifetime from 10.000 hours to 1000 hours or the lifetime remains less than 10%. This phenomena wasrecognized as a creep, which often happened at a high temperature operation even at Incoloy 800. So, the working condition,which was defined by the design calculation, has to be controlled preciously, to avoid the failure.Key words: Incoloy 800, creep, lifetime. Widyanto B. daft Suratman R.; Departemen Mesin, FT -ITB
