Long-Term Creep Performance of Ferritic SOC Interconnect Steel

Abstract

Crofer^® 22 H is a well-known commercial ferritic stainless steel for the construction of SOC interconnect plates. Its performance under creep loading conditions in the temperature range from 700 to 800 °C was evaluated against a pre-commercial trial steel to signify the impact of thermomechanical treatment history on long-term creep response. While the commercial grade prevailed in solution treated, i.e., low dislocation density, state, the trial steel was put into creep service in a deformed, i.e., high dislocation density, condition. Dislocations do play a major role in the early stages of the nucleation of strengthening Laves phase precipitates, and for this reason, sensitively impact the creep response of the materials in the primary stage of creep, which even affects the following (limited) secondary stage and especially the transition into the creep life dominating tertiary creep stage.

Keywords

Solid oxide cells / Interconnect / Steel / Creep / Microstructure

Acknowledgement

The authors gratefully acknowledge the continuous support of Forschungszentrum Jülich GmbH, especially the support of W. Lange, M. Braun and A. Moser in long-term creep testing, V. Gutzeit and J. Bartsch in metallographic preparation, E. Wessel in microstructural examination.

Author Contributions

Conceptualization, B.K.; Methodology, B.K.; Validation, T.F.; Formal Analysis, T.F.; Investigation, B.K. and T.F.; Resources, B.K.; Data Curation, T.F.; Writing—Original Draft Preparation, B.K.; Writing—Review & Editing, T.F.; Visualization, B.K. and T.F.; Supervision, B.K.; Project Administration, B.K.; Funding Acquisition, B.K.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not available.

Funding

Funding of steel development was provided by the German Ministry of Economy and Energy under grant numbers 0326879 and 0327766, which is greatly appreciated.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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