Effects of N and Cu on the precipitation and the creep life of 316 L austenitic stainless steel at 650 degrees C

Abstract

N and Cu were incorporated in 316L austenitic stainless steel in order to improve the creep life at 650 degrees C and 700 degrees C with a stress range of 100-250 MPa. An increased amount of N in solid solution strengthened the matrix and suppressed the coarsening of M23C6 precipitates, which improved the creep life. Low stresses allowed Cu-added alloys to rupture after the precipitation of the Cu-rich phase, which strengthens the matrix. Therefore, the addition of Cu enhanced the creep life only under low stresses while the positive effect of Cu was inconspicuous under high stresses. (C) 2016 Elsevier B.V. All rights reserved.