| The aging of the seal ring is closely related to the gas tightness of GIS.However,the aging characteristics of GIS seal ring are not clear yet.In order to study the aging characteristics of GIS seal rings,our paper detected the aging law,aging characteristics and aging mechanism of artificially accelerated aging seal rings and GIS retired seal rings.In the meantime,the effect of water（damp）and salt water（damp,salt）on the thermal aging characteristics of seal ring was studied.These studies provide a technical basis for the aging research of rubber seal rings.Firstly,a test platform for artificial accelerated aging and performance test of the seal ring was set up.A new index,deformation recovery ratio,was proposed to characterize the aging of seal rings.The arc-shaped specimens of new ethylene propylene diene monomer seal rings of different formulas were subjected to heat,compression two-factor accelerated aging.The arc-shaped specimens of new ethylene propylene diene monomer seal rings were subjected to accelerated aging at different temperatures.Compression set and deformation recovery ratio of arc-shaped samples after gradient aging time were measured.The correlation between deformation recovery ratio and compression set was established.The results showed that,the aging characteristics of seal rings of different formulas are different.The aging rate of seal rings at 120°C was significantly higher than that at 90°C and 105°C.Heat had a significant effect on the aging of seal rings.The aging law of artificially accelerated seal rings was an exponential model.As the aging time increases,the aging rate gradually decreased.The deformation recovery rate had a strong correlation with compression set,which could characterize the aging performance of operating or retired seal rings.Secondly,the new index,deformation recovery ratio was used to measure the performance of retired chloroprene rubber seal rings.The aging law model of the retired seal ring was established.The surface morphology and surface elements of retired seal ring were analyzed.The chemical changes that occur during the natural aging process of retired seal rings were analyzed through FTIR.The results showed that,the exponential model fit the relationship between DRR vs.service year.The surface of air side was found to be divided into two areas:a coarse area（air contact facing）and a flat area（flange contact facing）.These areas were separated by a distinct boundary.The air contact facing of seal ring was rather rough than that of the flange contact facing.The increase of fluorine（F）atoms and the decrease of carbon（C）atoms were the aging characteristics of the SF6 side of the seal rings.The carbonyl index of seal rings increased with serviced year.Oxidation and chain scission reactions occur during the aging process of seal rings.Last but not least,damp,salt,heat,compression multi-factor accelerated aging test platform was adopted.New ethylene propylene diene monomer seal ring samples were accelerated aged in groups under different combinations of aging factors,including heat,compression,damp and salt.The compression set and hardness change rate of seal ring samples after aging were tested.Scanning electron microscopy and electronic probes were used to analyze seal ring samples.The results showed that,water had a corrosive effect on the surface of the samples.Water intensified the chain scission and oxidation reaction of seal rings,leading to larger compression set.When exposed to damp,salt,heat and compression,damp and salt played synergistic effects.Saline had a strong corrosive effect on the seal rings.Aging of seal rings were dominated by chain scission. |
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