Reducing Temper Embrittlement by Lanthanide Additions

Abstract

This paper examines the temper embrittlement behavior of a series of 21/4%Cr-l%Mo steels with and without lanthanide metal (LnM) additions. The influence of LnM additions asmischmetal or as individual elements is assessed with respect to embrittlement behavior. Results show that LnM form harmless compounds in the matrix with impurities such as P, As, Sn and Sb, thus minimizing segregation-induced embrittlement. Optimum LnM levels well below those dictated from theoretical calculations are sufficient to trap the impurities for a given set of conditions. © 1985 TMS.