In industrial sealing applications, fluororubber (FKM) seals are highly favored for their outstanding resistance to high temperatures, oils, and chemicals. However, different application scenarios have varying requirements for sealing performance. Understanding how each key performance parameter of fluororubber affects sealing performance can help users make more precise selection and design decisions.

I. Main Performance Indicators and Their Influences    
Hardness (Shore A)    
Definition: The material's ability to resist indentation by external forces reflects the “softness” or “hardness” of the rubber.
Impact:    
High hardness (>75 Shore A): Strong resistance to extrusion, suitable for high-pressure environments; excellent wear resistance, commonly used in hydraulic seals and high-temperature valves.
Low hardness (<65 Shore A): Flexible and easy to install, with excellent conformability, making it suitable for sealing in low-pressure or complex structures, such as pneumatic systems.
Tensile strength (MPa)    
Definition: The maximum stress that a material can withstand before it fractures.
Impact:    
High strength (>15 MPa): High tear resistance, suitable for dynamic operating conditions, such as engine oil seals.
Low intensity (<10 MPa): Suitable for static or low-pressure sealing, with lower costs.
Elongation at break (%)    
Definition: The maximum strain ratio that a material can achieve before fracture.
Impact:    
High elongation at break (>250%): Adapts to complex deformations and is suitable for dynamic or vibrating environments.
Low elongation (<150%): Dimensionally stable and suitable for precision sealing, but installation requires careful handling.
Tensile stress at a specified elongation (MPa)    
Definition: The stress required to stretch a material to a specific strain (e.g., 100%).
Impact:    
High-tenacity stress (>8 MPa): High resilience and high sealing contact pressure, suitable for ultra-high-pressure operating conditions.
Low stress at low elongation (<4 MPa): Low friction, suitable for high-speed sealing, but attention must be paid to controlling the compression ratio.
Compression Strain (%)    
Definition: The proportion of deformation in a material that cannot be recovered after compression.
Impact:    
Low compression deformation rate (<20%): The sealing performance is long-lasting and particularly suitable for high-temperature or long-term pressurized environments.
High compression deformation rate (>25%): The sealing force decreases over time, so it’s important to pay attention to the operating temperature and material selection.

II. How to Select Indicators Based on Operating Conditions?

III. Common Failure Issues and Solutions    
Extrusion damage    
Reason: The hardness is too low or the stress at a specified elongation is insufficient.
Recommendation: Use materials with a hardness of 80 Shore A or higher, or use them in combination with PTFE retaining rings.
Permanent deformation leads to leakage.    
Reason: High compression deformation rate or low elongation rate.
Recommendation: Select FKM vulcanized with peroxide, and keep the compression set within a reasonable range.
Severe dynamic wear    
Reason: Insufficient tensile strength or excessive hardness.
Recommendation: Preferentially use high-strength materials (>18 MPa) or apply a surface wear-resistant coating.
 

IV. Quick Guide to Selection Recommendations    
Static seal: Focus on hardness and set stress; for example, the HT series is suitable for high-temperature static sealing at 310℃.
Dynamic sealing: Prioritize elongation at break and compression set, for example, HP01 and HP02 are suitable for high-frequency reciprocating motion.
Extreme Environment: Strictly control the compression deformation rate and tensile strength; we recommend perfluoroether FFKM materials, such as the CR series, for applications involving severe corrosion.

Conclusion    
　　The performance of fluororubber seals depends on the balanced interplay among multiple indicators. In high-pressure systems, attention should be paid to hardness and set tensile stress; for dynamic seals, focus should be placed on elongation at break and compression set; and in high-temperature or chemically corrosive environments, low compression set and sufficient tensile strength are particularly critical. Proper selection not only enhances sealing reliability but also extends the service life of equipment.
　　If you’d like to learn more about fluororubber sealing solutions tailored to your specific application conditions, feel free to contact our technical team for professional support!