Continuous operating temperature
Share the normal range and time spent at elevated temperature.
BY APPLICATION
High-Temperature O-Rings — Supply & Application Review
We supply O-rings and support material and application review for elevated-temperature requirements. Start with an existing specification, a replacement requirement or the operating conditions you know.
Request a Technical Review
Initial response within 12 hours.
01 / HIGH TEMPERATURE
Describe the Temperature Conditions
Evaluate temperature, exposure duration and cycle frequency together; a brief peak is not equivalent to continuous service at the same temperature.
Short-term peak temperature
Identify the highest expected temperature, peak duration and frequency.
Heating and cooling cycles
Describe start-up, shutdown and cleaning cycles, including how often and how quickly temperatures change.
02 / HIGH TEMPERATURE
How High Temperature Affects O-Ring Performance
Thermal Aging
Prolonged heat exposure can cause oxidation, further cross-linking and other irreversible changes, depending on the compound and environment. Hardening, cracking and deterioration of mechanical properties are possible outcomes, not universal symptoms.
Compression Set
Sustained compression at elevated temperature can reduce recovery after unloading. Reduced recovery can contribute to leakage when the seal must accommodate cooling, movement or changes in the sealing gap, even without visible damage.
Hardening and Loss of Elasticity
An aged seal may become less able to follow mating surfaces and maintain sealing contact. Hardening or cracks alone do not identify a unique cause; review the compound, media, thermal history and installation together.
ASTM D395 evaluates residual deformation after specified compression and recovery conditions; a compression set value is not a direct measurement of sealing force. ASTM D573 evaluates changes in rubber properties after air-oven aging. These methods do not establish actual seal life in every service environment and are not evidence that FLUID has performed these tests.
03 / HIGH TEMPERATURE
Evaluating Temperature and Media Together
Hot air and oxidizing environments: oxygen exposure can influence thermal aging. Performance in hot air cannot be assumed to represent performance in hot oil, steam or chemical media.
Hot oils and process fluids: review the exact fluid, additives, mixtures and concentration. Temperature can change the rate and extent of swelling, extraction or other material changes.
Steam, hot water and cleaning media: review wet and dry exposure, cleaning chemistry and transitions between process and cleaning conditions. A compound suitable for one hot medium may be unsuitable for another.
Exposure duration and thermal cycling: consider cumulative time at temperature and repeated heating and cooling. Assess the specific compound under the combined conditions rather than relying on a general material temperature range.
04 / HIGH TEMPERATURE
Material Selection for High-Temperature Sealing
A material family name alone does not establish a temperature limit or suitability for your application. Specific formulation, continuous and peak temperatures, media, contact time and seal construction must be assessed together.
FKM, FFKM, VMQ / Silicone, EPDM, HNBR and FEPM / AFLAS are examples of material families to evaluate, not a complete list, temperature ranking or confirmation that every compound is available. FFKM is not automatically the best choice for every high-temperature application.
Solid PTFE has much less elastic recovery than rubber and can creep under sustained loading. FEP/PFA encapsulated O-rings combine a fluoropolymer jacket with an elastomer core; both components and installation constraints matter. Neither construction is a direct equivalent replacement for a conventional rubber O-ring.
Have a specification? Share the compound reference, drawing and documentation requirements. Selecting or replacing a seal? Share the operating conditions and service history. FLUID supports application review and supply evaluation; the specific material and supply option are confirmed for the project.
05 / HIGH TEMPERATURE
Thermal Expansion and Seal Design
Thermal Expansion
Elastomers generally expand more than metal glands as temperature rises. The gland must accommodate the resulting volume change, together with any fluid-induced swell, to avoid excessive fill.
Compression and Gland Fill
Review squeeze, available groove space and the tolerance stack across the operating range. A satisfactory room-temperature fit does not by itself establish suitable compression or gland fill at elevated temperature.
Pressure and Extrusion
Heat-related softening, pressure and the effective clearance can combine to increase extrusion risk. Include thermal dimensional changes and pressure peaks when reviewing the sealing gap.
Static and Dynamic Sealing
Static seals must maintain contact through thermal changes. Dynamic seals also require review of friction, wear, lubrication and friction-generated heat; the seal contact temperature may differ from the measured bulk fluid temperature.
06 / REVIEW
Share Your High-Temperature Requirements
You do not need a complete specification to begin. Send what is available, and we will clarify the next information needed.
- 01
Continuous operating temperature and exposure time.
- 02
Peak temperature, peak duration and heating / cooling cycle frequency.
- 03
Sealed media, mixtures, concentrations and cleaning exposure.
- 04
Operating and peak pressure; static or dynamic operation and motion details.
- 05
O-ring dimensions, tolerances, gland information or available drawings.
- 06
Existing compound, service history and any leakage, hardening or other failure observations.
07 / RELATED PATHS
Continue the technical discussion
These are discussion paths, not a temperature ranking or a suitability recommendation. Specific compounds and constructions need review against the application and are not assumed to be interchangeable.
08 / TECHNICAL REVIEW FAQ
High-Temperature O-Ring FAQ
How does continuous temperature differ from a short-term temperature peak?
Continuous service exposes the seal to heat for longer periods. A peak must be assessed with its duration and frequency; a short-term limit does not establish continuous-service suitability.
Why do O-rings harden or crack during high-temperature service?
Thermal aging can involve oxidation, further cross-linking and loss of compound constituents. Media and other damage mechanisms can produce similar symptoms, so appearance alone cannot confirm the cause.
Why can compression set contribute to leakage at elevated temperatures?
Reduced recovery can limit the seal's ability to accommodate changing gaps or cooling after sustained compression. Leakage also depends on squeeze, geometry, pressure and material condition; a compression set result alone does not quantify sealing force.
Is FFKM always the best choice for high-temperature O-rings?
No. Suitability depends on the specific compound, media, temperature history, mechanical requirements and seal design. Other material families may be appropriate; FFKM alone does not resolve every sealing problem.
How do thermal expansion and gland design affect high-temperature sealing?
Different expansion rates change the seal volume and available gland space. Review squeeze, gland fill, tolerances and any fluid swelling over the operating range to avoid overfilling or inadequate sealing contact.
NEXT STEP
Discuss Your High-Temperature O-Ring Requirement
Whether you have an existing specification or need help reviewing options, start with the requirement you have.
Request a Technical Review
Initial response within 12 hours.