Groove Finish Recommendation for Metal Seal
Classification：Company Updates Release date： 2022-02-23 12:50
Groove finish of the mating hardware is a critical aspect for metal sealing. To achieve that target sealing effect, Sonkit recommends the minimum groove finish for different medium are listed as below table:
Metals do not behave like elastomers which can be compressed, thus having a smoother or well matched groove surface is crucial for good metal sealing. Sonkit recommends a groove finishes with a roughness rate (Ra) between 1.6 and 2.5 for metal seals prepared for viscous media. Similarly, Sonkit recommends RA between 0.4 and 0.8 for liquid media and RA between 0.2 and 0.6 for vacuum media. These parameters are the standard that Sonkit has tested in applied environments. Depending on the application’s required sealing performance, Sonkit can produce metal seals that match groove finishes beyond the given ranges. For example, surfaces in excess of 3 RA will not have a bubble tight sealing effect (leakage rate of 1x10^4 cc/sec), but this could be sufficient in certain applications. As such, Sonkit strongly recommends customers to contact our engineer team for bespoke product design.
In certain applications, higher RA surface roughness can be negated with the help of coating applied to the metal seal. The image below shows how coating can navigate the peaks and valleys of the hardware surface and achieve the desired sealing effect.
In summary, the groove finish roughness can adversely impact the sealing effect of metal rings. Sonkit offers free technical training for better installing metal seals. For further information please visit our website or send an email to johnny@sonkit.cn.
