Common materials used for seal springs, specifically focusing on the components that interact with the springs themselves, encompass a range of elastomers and metals. These materials are selected based on their mechanical properties, chemical resistance, and compatibility with the operating environment of the sealed device. Here’s a breakdown of the materials mentioned across the sources:
Metal Springs
Stainless Steel: Often the most common material for metal springs, including Cantilever, Canted Coil, and Helical Coil springs. Stainless steel is chosen for its tensile strength, corrosion resistance, and compatibility with a wide range of fluids and temperatures. It’s particularly favored in industrial and aerospace hydraulic systems.
Elgiloy: An alloy known for its high tensile strength and resistance to oxidation and corrosion. It’s often used in applications requiring high performance at elevated temperatures. Despite being more expensive per pound, its superior properties make it a viable option for high-volume production, sometimes replacing more costly options like 17-7 Stainless Steel.
Hastelloy: Another corrosion-resistant alloy, Hastelloy is used in environments where resistance to specific chemicals or temperatures is critical. Its use is more niche compared to stainless steel but is chosen for its exceptional durability in harsh conditions.
Polymers
PEEK (Poly-ether Ketone): While primarily considered a seal material, PEEK can also be used as a spring in polymer-style seals. It’s valued for its high melting point, excellent chemical resistance, and mechanical strength. PEEK springs are particularly useful in radiation service applications, where metals may not be desirable.
Alternative Materials
Inconel®: Known for its high-temperature and corrosion-resistant properties, Inconel is used in seals where exposure to extreme temperatures and corrosive environments is expected. It’s a specialized material offering superior performance in critical applications.
Specialty Alloys: For more demanding applications, alloys like Elgiloy and Hastelloy are employed. These materials offer enhanced performance in terms of tensile strength, corrosion resistance, and temperature tolerance, making them suitable for applications where standard stainless steels may fall short.
Selection Criteria
Choosing the right spring material involves considering several factors, including:
Compatibility with System Fluids: The material must be compatible with the fluids or substances the seal will encounter to prevent degradation or failure.
Temperature Range: The material should be able to withstand the operational temperature range of the application without losing its structural integrity.
Cost and Availability: Economic considerations often influence the choice of material, especially when comparing specialty metals to more common alternatives like stainless steel.
By carefully selecting the material based on these criteria, engineers can ensure that seal springs provide optimal performance and longevity in their intended applications.
