Combined equilibrium and non-equilibrium segregation treatment of temper embrittlement in low alloy steels

Embrittlement is an important factor for low alloy ferritic steels used for components and structures in the power and petrochemical industries when e xposed to a higher temperature. The embrittlement may be classified into no nhardening embrittlement and hardening embrittlement, The non-hardening emb rittlement, for example temper embrittlement, originates from grain boundar y segregation of impurity elements such as phosphorus. To predict this segr egation behaviour, a model is established by simplifying a low alloy steel as a dilute Fe- C - Mo - P quaternary alloy and modifying previous models. This model is applied to segregation predictions in a 2.25Cr-1Mo steel subj ected to a complex heat treatment cycle, (C) 2001 IoM Communications Ltd.