PEEK data for low temp service

[Tuckabag]

Can someone point me in the direction of some data/papers re performance of PEEK at (relatively) low temperatures (-50deg C)?

All the data I've found so far touts the high temp performance, but I cant find anything re lower temps.
We are looking at swapping out PCTFE seats for PEEK ones. Seat arrangement is a basic static seat with 316SS poppet operating around 6,000kPa.
We use PEEK seats on the same device for high pressure service, but we don't see the same temp swings as we do on this particular service.
The issue we are experiencing is that during temp changes as part of the process cycle, we are seeing deformation of the PCTFE seat @ approx +130deg C.
The PCTFE provides us with Class VI shutoff across our pressure ranges (0-30,000kPa), we've found the PEEK can be a bit hit or miss at pressures below around 3,000kPa, so my concern is that it will only get worse the colder it gets.

Thanks.

 

[mighoser]

Have you looked at Mica Reinforced PTFE like Fluorosint HPV or 500? Should work at hot and cold temps as you described. Glass filled PEEK isn't recommended for use below -20C.

 

[Tuckabag]

Thanks Mighoser, will look into those.
We've had Victrex recommend CT100 grade PEEK for this application.
If we end up using it, I will come back here with some results.
Cheers.

 

[cap1a79]

Refer to "brittleness temperature" in TABLE 5 of ISO-23936-1.
As per the table, PEEK can be used down to -65 C.

PEEK - Maximum operating temperature up to 250 C, Brittleness temperature down to -65 C.

Lee SiHyoung,
WorleyParsons Oman Engineering,

 

[Tuckabag]

Thanks, will check this out as well.

 

[WKTaylor]

Tuckabag...

Suggest You re-submit this question in a more-appropriate forum... Polymer Engineering

https://www.eng-tips.com/threadminder.cfm?pid=334

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
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[Tuckabag]

OK, will do. Thanks.