Phosphorus segregation in CrMoV low-alloy steels

The phosphorus segregation at temperatures of 773 and 853 K has been studie d in two low-alloy Cr-0.4 Mo-0.5 V steels with different chromium contents (0.85 and 2.5 mass%). Segregation of elements on grain boundaries was measu red by means of Auger electron spectroscopy. Transmission electron microsco py techniques were used for the identification of secondary phases in the s teels investigated. A significant influence of aging temperature on the kin etics and equilibrium value of phosphorus grain-boundary concentration was observed. Both lower temperature and higher bulk chromium content were foun d to increase the grain-boundary phosphorus segregation. This is in agreeme nt with the Langmuir-McLean theory, the model of phosphorus-carbon site com petition, and also confirms the significant effect of carbide formation on phosphorus segregation in steels. (C) 2000 Elsevier Science B.V. All rights reserved.