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FKM vs FFKM O-Rings: Which To Choose?
Choosing the right material for O-rings is critical for longer service life, equipment safety, and cost savings for the business. FKM and FFKM O-rings are highly regarded for their outstanding performance in extreme environments.
While both FKM and FFKM are reliable under demanding chemical and temperature conditions, they have distinct properties. For instance, FFKM has a higher range of operating temperatures. The materials may look similar, but they also have differences in chemical resistance, mechanical strength, and temperature set.
An Overview of FKM and FFKM
FKM, also called fluoroelastomer, is a carbon-based synthetic rubber first made in the 1950s. It was used to fill the demand for reliable seals in the aerospace industry.
Modern FKM components can remain functional in temperatures exceeding 200°C. The material is also resistant to a range of chemicals and pressures. One notable limitation of FKM is its poor resistance to hot water and hydraulic fluid-based phosphate esters.
Fortunately, the addition of special compounds by O-ring manufacturers makes the material more usable in such environments.
Notably, FKM materials are not recommended for amines and alkaline fluids because they contain C-H bonds.
FFKM is another synthetic rubber in the family of fluoroelastomers. However, it contains a higher fluorine level than the common FKM. FFKM became commercially available later than FKM did, in the 1960s.
Like FKM, FFKM materials are engineered for excellent performance in high chemical and temperature environments. However, FFKM performs much better in these environments. FFKM O-rings can be reliably used in temperatures over 300°C.
Advantages of FKM O-rings
The advantages of FKM O-rings include;
- Good mechanical strength
- Low compression set
- Relatively cost-effective
- Dependable performance up to about 200°C
Advantages of FFKM O-rings
The advantages of FFKM O-rings include;
- High temperature resistance - 300°C
- Superior performance in high-purity and aggressive environments
- Excellent performance in chemical processing, pharmaceutical, and semiconductor manufacturing
- Near-universal chemical resistance
FKM vs FFKM O-Rings: Main Differences
The main differences between FKM and FFKM are in chemical resistance, temperature stability, mechanical strength, cost, and wear resistance.
The table below highlights the differences.
|
Element |
FKM |
FFKM |
|
Chemical resistance |
Excellent for most acids, oils, and fuels |
Near-perfect - resists most chemicals, including the most aggressive ones |
|
Temperature stability |
Up to ~200°C continuous |
Up to ~300°C continuous |
|
Mechanical strength |
Good elasticity and compression set |
Maintains dimensional integrity even in extreme conditions, but has lower mechanical strength |
|
Cost |
Cost-effective for industrial use |
Premium price; targeted to critical applications |
|
Wear resistance |
Good abrasion resistance |
More of thermal resistance and chemical resistance than wear resistance |
In summary:
FKM: FKM resists a broad array of chemicals, including acids, oil, and solvents. This capability makes FKM components perfect for many automotive and industrial applications.
FFKM: FFKM has near-universal capability in chemical-ridden environments. Its O-rings can withstand strong bases, concentrated acids, and other aggressive media.
FKM vs FFKM O-Rings: Common Applications
FKM O-rings are mostly used in:
- Aerospace Industry: Engine systems, hydraulic systems, fuel systems
- Automotive: Combustion engines, fuel system,
- Oil & Gas Industry: Pipeline connections, control valves, drilling equipment, compressors
- Food Industry: Valves, pumps, conveyors, mixers, hot water systems
FFKM O-rings are mostly used in:
- High-Purity Applications: Ultra-pure water (UPW) systems, pharmaceutical filling lines, semiconductor wafer processing equipment
- Aggressive Chemical Environments: Industrial cleaning equipment, chemical processing reactors
- Cleanrooms: Sterile filling systems, optics manufacturing, vacuum chambers in semiconductor fabrication
Choosing FKM vs FFKM O-Rings
When choosing between FKM and FFKM O-rings, here are some important questions to ask the O-ring manufacturer:
- Is it a high-temperature or low-temperature application?
- How long do you want the O-ring to last?
- What are the maintenance requirements?
- What type of chemical environment will the O-ring be exposed to?
- What is my budget?
If cost is a major consideration and the temperature and chemical conditions are within the standard ranges, FKM O-rings are probably what you need.
FFKM O-rings could be a better choice if the conditions are more extreme and the failure risk is significantly higher. However, one notable thing is that FFKM O-rings are costlier.
Fortunately, you don’t have to make this decision alone.
Work With the Experts for O-Ring Solutions
FOREVER SEALS offers a range of O-ring materials, including NBR, FKM, silicone, EPDM, ACM, AFLAS, FFKM, and more. With extensive experience as O-ring manufacturer in all these options, we help you select the ideal material.
Our FKM and FFKM O-rings meet the requirements for performance, safety, and regulatory compliance. They are recommended for their high chemical corrosion resistance and temperature resistance.
Our team is extensively experienced and committed to world-class quality. We can help you choose between the two materials, and further recommend the perfect O-ring seal size for your static and dynamic sealing needs.
Conclusion
FKM vs FFKM O-rings offer distinct advantages and limitations. Understanding the differences helps in choosing the safer, more cost-effective, more durable, and better-performing components.
The differences in wear resistance, price, short-term resilience, weathering resistance, and chemical resistance should guide this selection process.
If you need an O-ring manufacturer, and further assistance in identifying the best material for your O-ring project, talk to the experts at FOREVER SEALS.
FAQ
-
Why are FFKM O-rings so expensive?
The significantly higher cost of FFKM O-rings compared to standard O-rings is due to the material’s special manufacturing for extreme applications. There are very few alternatives to FFKM for certain applications, for example, contamination-sensitive areas and ultra-high temperature sealing applications in aerospace systems.
-
Is fluorocarbon FKM the same as FFKM?
No, fluorocarbon FKM is not the same as FFKM. Fluorocarbon FKM is a different way of saying FKM. The term “fluorocarbon” simply describes the fluorinated hydrocarbon content in FKM. FFKM is a different carbon-based synthetic rubber with advanced properties.
-
Is Viton the same as FFKM?
No, Viton™ is a brand of (FKM) synthetic rubber. Viton™ falls under the global performance chemicals provider, Chemours, which has a branch in Shanghai and is headquartered in Wilmington, Delaware, US.
