a seal is held at a high temperature for a period of time, the
elastomer will deteriorate to some extent. In particular, the
compression set and volume will change. The hardness of the elastomer
changes in two stages. At first, the seal will become softer.
This can cause problems because the elastomer may flow through
the clearance gap. Second, if the seal remains too hot, chemical
changes will occur with the elastomer and the it will become harder.
the right material for a high temperature seal is very important
. FKM fluorocarbon seals resist hardening and embrittlement for more
than 10,000 hours in air up to 204°C, and they withstand surges
up to 315°C. Also, with the thermal capability of FKM fluorocarbon,
some users can increase operating temperatures to improve productivity
or gain other production advantages.
is an even better choice for a high temperature seal. Even after
long-term exposure to temperatures up to 316°C (600°F),
Kalrez® retains its elasticity and recovery properties better
than other elastomers.
engineers are always happy to talk to you about designing an o-ring
or seal to resist heat. The more resistance to heat an elastomer
is, the more the cost goes up. It is more cost effective to carefully
choose the elastomer with the right temperature tolerance as opposed to buying the very best elastomer that will withstand the most heat.