The effect of alloying on 485°C embrittlement

Abstract

An examination has been made of the effects of carbon, nitrogen, molybdenum, titanium, and niobium on the occurrence of 485°C embrittlement in 25%Cr ferritic stainless steels. All these alloying additions increase the rate of precipitation, as measured by the rate of age hardening. In general the tensile strength and ductility reflected the effects of the α′ precipitation, but it is shown that a marked refinement of the ferrite grain size can offset the embrittling effects of even heavy α′ precipitation. Various suggestions are made to explain why the alloying elements studied accelerate the rate of α′ precipitation.