Enhancement of Creep Life by Niobium Carbide in Fe-30Cr-3Al Ferritic Heat-Resistant Steel

Abstract

Finely distributed niobium carbides in the initial microstructure prohibit dislocation movement and extend creep life of Laves phase-strengthened Fe-30Cr-3Al-Nb heat-resistant steel at temperature > 973 K (700 A degrees C). Especially, steel that contains 1 wt pct Nb shows promising creep properties, because the fine precipitates increase high-temperature strength, and the small grain size decreases formation of weak precipitate-free zones near grain boundaries after solution treatment or during creep tests.