To maintain the integrity of applications of the duplex stainless stee
ls currently in service, a study was conducted to develop a method to
nondestructively estimate their Charpy-impact energy at room temperatu
re. It was found that hardness of the ferrite phase is a reliable indi
cator of the process of embrittlement during long-term heating of dupl
ex stainless steels. However, further information on the ferrite phase
and the austenite phase is required for the estimation of Charpy-impa
ct energy. An equation composed of the hardness values of ferrite and
austenite phases, the ferrite content and the average spacing of ferri
te phase islands was presented as a method applicable to the nondestru
ctive estimation of Charpy-impact energy at room temperature. (C) 1998
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