Influence of Ageing on Sealability of HNBR, EPDM and FKM O-rings
- At BAM, which is the federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the containers. Besides examining the low-temperature behaviour and irradiation effects of elastomeric seals, it is our goal to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1 year. In order to assess sealability, O-rings are aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings are aged as well. FurtherAt BAM, which is the federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the containers. Besides examining the low-temperature behaviour and irradiation effects of elastomeric seals, it is our goal to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1 year. In order to assess sealability, O-rings are aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings are aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, hardness is measured for information about the change of mechanical properties. The experimental results indicate that while hardness, CSR and CS show considerable degradation effects, the leakage rate stays constant or even decreases until shrinkage and the loss of resilience of the aged seal leads to the formation of a leakage path. This indicates that static leakage rate, which is the only available direct seal performance criterion, has only limited sensitivity for the degradation of the seal material.…
Autor*innen: | Anja KömmlingORCiD, Matthias JaunichORCiD, Dietmar Wolff |
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Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Graue Literatur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | International Sealing Conference 2016 |
Jahr der Erstveröffentlichung: | 2016 |
Verlag: | VDMA |
Jahrgang/Band: | 2016 |
Erste Seite: | 551 |
Letzte Seite: | 563 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik | |
Freie Schlagwörter: | Degradation; Rubber; Seal |
Veranstaltung: | International Sealing Conference |
Veranstaltungsort: | Stuttgart, Germany |
Beginndatum der Veranstaltung: | 12.10.2016 |
Enddatum der Veranstaltung: | 13.10.2016 |
ISBN: | 978-3-8163-0674-9 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 01.11.2016 |
Referierte Publikation: | Nein |