High Interstitial Stainless Austenitic Steels

Abstract

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Considerations in the Design of Formable Austenitic Stainless Steels Based on Deformation-Induced Processes

“…Alloying with higher amounts of N or very high levels of (C + N) will increase the solution-annealing temperature needed for the full dissolution of carbides and nitrides. On this basis, the complete dissolution of carbides and nitrides in the stainless steel Fe-19Cr-19Mn-0.49C-0.58N [60] appears improbable. In fact, the presence of Cr-rich carbides and nitrides is not desirable since Cr, C, and N will then not contribute to the stabilization of austenite.…”

New Developments in Martensitic Stainless Steels Containing C + N

“…[5,6] In case of stainless steels the latter leads to an increase in corrosion resistance, since the tendency for precipitation of chromium-rich phases is decreased. [7] Furthermore, nitrogen dissolved in the matrix has a positive effect on the resistance to pitting corrosion, which can be directly determined in the Pitting Resistance Equivalent Number (PREN). [8] The negative aspect of N in martensitic steels is the increasing stability of the austenitic phase, leading to retained austenite (RA) after quenching and thus to a reduced hardness.…”

The influence of the nitrogen/nickel‐ratio on the cyclic behavior of austenitic high strength steels with twinning‐induced plasticity and transformation‐induced plasticity effects

“…Still recently developed CrMnCN steels also bring about a higher fatigue limit, which could even be further improved by 20 % cold-working [12][13][14][15]. With these so-called austenitic high interstitial steels both carbon and nitrogen are of similar importance for all properties depending on the sum of carbon + nitrogen and its ratio carbon/nitrogen [16].…”

“…The reasons for the unique combination of strength and ductility have been investigated intensively and can be explained mainly by the relatively low stacking fault energy (SFE) of these steels (by adding manganese), the effective solidsolution hardening by interstitials (by carbon + nitrogen) and the extraordinary high density of free electrons (by carbon + nitrogen and carbon/nitrogen) [17]. At very low stacking fault energy's this leads to the phase transformation into a'-martensite for high-manganese, nitrogen-free alloys or to emartensite in case of high-nitrogen alloys.…”