High-interstitial stainless austenitic steel castings

Abstract

Interstitial atoms are most effective in strengthening austenitic steels. In stainless grades, chromium strongly reduces the solubility limit of carbon. High-nitrogen contents require costly pressure or powder metallurgy to dissolve N in the melt. The combination of both elements comes with a high-interstitial solubility at normal pressure of air. Sand casting with 18 mass% Cr and Mn each and 0.85 mass% (C + N) were industrially produced. The investigation revealed: proof strength Rp0.2 = 457 [MPa], true fracture strength R = 1714 [MPa], fracture elongation A = 44%, notch impact toughness KV = 290 J combined with a DBTT of -94°C, an impact wear resistance comparable to Hadfield steel X120Mn12 but combined with a good corrosion resistance. Deep freezing and cold working does not effect the low relative magnetic permeability. This unique combination of properties offers advantages in application. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.