The Effect of Interaction of Interstitial Solute Elements on the High Temperature Strength of 18Cr-12Ni Heat Resisting Steel

Abstract

An investigation was made on the interactions induced by the simultaneous additions of interstitial solute elements such as C, N, and B, for the high temperature strength of 18 Cr-12 Ni heat resisting steel. The interactions were correlated with the age-hardening response, the softening characteristics after cold rolling and the structural change during creep.
By the duplex additions of N and B, the obvious interaction that decreased the creep rupture strength lower than the sum of individual contributions was produced. This interaction was attributed in part to the strengthening of matrix more than the boundary due to precipitation hardening and in part to promoting the creep rupture by B addition in the coexistence with N. By the duplex additions of N and C, the deleterious interaction was also produced after prolonged time at 700°C. From these phenomena, the authors suggested a general condition for producing the interaction by the simultaneous additions of alloying elements for the high temperature strength.