Welded high-temperature power plant components can experience a greater ris
k of failure by creep during service, when compared to similar as-wrought c
omponents. The heat-affected zone (HAZ) of alloy steels is usually the regi
on of a weldment exhibiting poor mechanical properties. The arc welding of
an ASTM A470, Class 8-rotor steel in this study identified the intercritica
l heat affected zone (ICHAZ) as the weakest region in terms of creep ruptur
e life. The type of welding procedure significantly affects this region, bu
t most important are the welding parameters utilized. Because of the micros
tructural heterogeneity of the HAZ and sensitivity of these microstructures
to changes when exposed to elevated temperatures, their performance at lat
er times is difficult to predict. Extrapolation techniques are limited in v
alue for predicting service lives of homogeneous materials, because these d
o not incorporate the microstructure changes of the materials during high t
emperature operation. They are even less useful for predicting the operatin
g lives of weldments. This paper considers the creep performance and struct
ure stability of the ICHAZ of 12 percent Cr and 21/r-1 Mo vanadium modified
weldments produced on a retired CrMo V rotor steel. [S0094-4289(00)00303-0
].