A new equation for the Cr equivalent in 9 to 12 Pct Cr steels

Abstract

In advanced 9 to 12 pct Cr steels, the Cr equivalent is used as a measure to check the formation of delta-ferrite. In the present analysis, 29 alloys of varying composition were vacuum induction melted, and the amounts of delta-ferrite were measured in as-tempered conditions. Based on this and previous results on 9 to 12 pct Cr steels, a new equation for the Cr equivalent is proposed and correlated with the amount of delta-ferrite formation. Results indicate that the new Cr equivalent equation shows better correlation than previous equations and predicts the amount of delta-ferrite formed reasonably well.