What Are O-Rings & How They Work
Ever wondered how a tiny rubber ring can stop a powerful hydraulic system from leaking? That’s the magic of an O-ring — small but mighty, simple yet essential.
At HENGOSEAL, we manufacture and export industrial-grade O-rings for over 20 countries. Whether you're sourcing for hydraulic cylinders, pneumatic equipment, or automotive engines, the right O-ring makes all the difference.
What Is an O-Ring?
An O-ring is a circular elastomer seal used to block the passage of fluids or gases between mechanical parts. Its simplicity and effectiveness make it the most commonly used sealing solution worldwide.
👉 For a broader overview, read our full O-Ring Seal Guide
How Do O-Rings Actually Seal?
When placed in a groove and compressed between two surfaces, the O-ring deforms elastically. This creates a seal that resists pressure, temperature changes, and vibration.
In hydraulic systems, this deformation is key to leak-free performance.
→ Learn more in our Hydraulic Seal Guide
If you're working in extreme-pressure environments, check out this comparison of durable O-ring solutions for high-pressure hydraulics.
What Are O-Rings Made Of?
The material you choose matters just as much as the size or shape. Here’s a quick overview:
| Material | Temperature Range (°C) | Key Strengths | Common Applications |
|---|---|---|---|
| NBR (Nitrile) | -40 to 120 | Oil resistance, low cost | Fuel systems, hydraulics |
| FKM (Viton®) | -20 to 230 | High temp, chemical resistant | Aerospace, engine seals |
| EPDM | -50 to 150 | Weather & ozone resistant | Outdoor, HVAC |
| PTFE | -200 to 260 | Inert, chemical proof | Medical, food, lab seals |
Which O-Ring Material Should I Choose?
Choosing the right compound depends on:
- Temperature: For high heat, use FKM or PTFE.
- Oil exposure: Go with Nitrile O-rings in automotive settings.
- Outdoor environments: Choose EPDM to handle UV and ozone.
- Aggressive chemicals: Rely on PTFE for maximum resistance.
💡 Still comparing options? Read our deep dive on Silicone vs FKM O-rings to choose the right material for complex environments.
How Do I Measure O-Ring Size?
To ensure proper fit, always measure:
- ID (Inner Diameter)
- OD (Outer Diameter)
- CS (Cross-section thickness)
Having trouble? Our guide can help:
📏 How to Measure O-Ring Size
What Is the Lifespan of an O-Ring?
On average, O-rings last 5 to 10 years, depending on:
- Material type
- Operating temperature
- Contact fluids
Poor storage or chemical mismatch can cause early failures.
Can O-Rings Handle High Pressure?
Yes — especially in hydraulic cylinders and rotary shafts.
One real-world case:
A manufacturer struggled with frequent failures at 2500 PSI and 180°C. By switching to FKM O-rings:
✅ Leakage reduced by 75%
✅ Seal life extended 5×
✅ Maintenance costs dropped 40%
Want something similar? Start with our O-Ring Assortment Kit
What Causes O-Ring Failure?
- Wrong material for the chemical or temperature
- Improper installation (twisting, over-stretching)
- Over-compression causing cracks or flattening
- Reusing O-rings — elasticity drops after each cycle
📚 Check our guide on Why Seals Fail
Can I Reuse an O-Ring?
Generally not. Once compressed and aged, the material loses flexibility. Always use new rings during repairs.
How Much Do O-Rings Cost?
O-ring pricing varies by:
- Material (NBR is cheaper, FKM & PTFE are premium)
- Size and tolerance
- Quantity (bulk orders save more)
👉 For full pricing strategies and tips, read our O-Ring Cost & Selection Guide
Why Source O-Rings from HENGOSEAL?
- 🌍 Trusted by buyers in 20+ countries
- 🧪 Factory-tested, export-ready
- 🔩 Wide selection including NBR, FKM, EPDM, PTFE
- 📦 Fast shipping, no MOQ, OEM support
📧 [email protected] | 📱 WhatsApp: +86 17622979498
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