MATERIAL SELECTION
Choose the Rubber Compound Before You Choose the Color
An O-ring can have the correct dimensions and still fail within days when the compound is wrong. Check the actual fluid, cleaning chemicals, continuous temperature, peak temperature, pressure, motion, exposure, and expected service life before approving the material.
| Material | Practical Starting Point | Confirm Before Release |
|---|---|---|
| NBR | Hydraulic oil, lubricants, grease, pumps, valves and general machinery | High heat, outdoor ozone, ketones, strong acids and aggressive solvents |
| FKM | Fuel, hot oil, automotive systems and selected chemical service | Ketones, amines, steam and the exact chemical concentration |
| EPDM | Water, glycol coolant, outdoor equipment, ozone and weather exposure | Petroleum oil, fuel, grease and certificate coverage for potable water |
| Silicone | Wide temperature cycles, electrical equipment and clean processing equipment | Abrasion, high-pressure dynamic movement and fluid compatibility |
| HNBR | Higher-temperature hydraulic, automotive and wear-sensitive service | Low-temperature flexibility, chemical exposure and project cost |
| FFKM | Critical chemical, semiconductor, pharmaceutical and high-temperature service | Exact chemical exposure, temperature cycle, downtime risk and compound grade |
A published temperature range is only a screening value. Actual service life changes with fluid concentration, pressure, time at temperature, movement, groove design, and compression.
APPLICATIONS
Match the O-Ring to the Equipment and Failure Risk
Hydraulic and Pneumatic Cylinders, pumps, valves, fittings and actuators. Check oil type, pressure, movement, hardness and extrusion clearance.
Pumps and Valves Valve bodies, stems, pump housings and pipe connections. Confirm the fluid, pressure cycle and installation groove.
Water Systems Plumbing, filtration, water treatment and sanitary fittings. Use an oil-free material and verify the required approval scope.
Food Processing Pumps, valves, filling equipment and sanitary connections. Confirm food-contact requirements and cleaning chemicals.
Automotive and Mobile Equipment Oil, fuel, coolant, air-conditioning and hydraulic systems. Temperature cycling and fluid changes need separate review.
Chemical Equipment Metering pumps, dosing systems and process equipment. Send the exact chemical name, concentration and temperature.
RFQ CHECKLIST
Information Needed for Material Review and Quotation
1. Working fluid or chemical name
2. Fluid concentration
3. Continuous and peak temperature
4. Working and test pressure
5. Static, reciprocating or rotary use
6. Inside diameter and cross section
7. Groove drawing or equipment drawing
8. Hardness and tolerance
9. Approval or compliance requirement
10. Order quantity and annual demand
Size Alone Is Not Enough
ID × cross section identifies the basic part. It does not confirm material, hardness, pressure capability, dynamic suitability, or chemical resistance.
For an existing assembly, send the groove dimensions and failure condition. A flattened, swollen, cracked, hardened, cut, or extruded O-ring points to different corrections.
STANDARD AND CUSTOM SUPPLY
Control the Drawing, Compound and Inspection Method
Standard sizes can follow AS568, ISO 3601, metric or inch dimensions. Non-standard O-rings can be developed from a drawing, groove specification or sample. For repeat orders, keep the approved compound, drawing revision, hardness, tolerance, inspection method and packaging label under the same order record.
Application Review
Material Confirmation
Drawing or Sample
Sample Inspection
Batch Production
Compliance Must Match the Exact Compound
A certificate does not automatically cover every EPDM, silicone or NBR compound. Confirm the certificate holder, compound reference, hardness, color, intended contact condition and validity before placing a regulated order.
Review Certification InformationTechnical Reading
Static vs Dynamic O-Ring Applications
Common O-Ring Failure Patterns
FAQ
O-Ring Ordering Questions
Can one O-ring material handle both petroleum oil and hot water?
Usually not. NBR is a practical starting point for petroleum oil, while EPDM is commonly evaluated for water, glycol and weather exposure. The final choice depends on temperature, fluid additives and service time.
What dimensions are required for an O-ring quotation?
Send the inside diameter and cross section. For a new design or recurring leakage problem, include the groove dimensions, mating clearance and drawing.
When should a backup ring be considered?
Review a backup ring when pressure and extrusion clearance can push the elastomer into the gap. Pressure direction, groove space, temperature and O-ring hardness all affect the decision.
Can an old O-ring sample be copied directly?
A used sample may be swollen, worn, flattened or permanently stretched. Send the sample together with the groove size, equipment information and working fluid to avoid copying a damaged dimension.
Are standard and custom sizes available?
Standard AS568, ISO 3601, metric and inch dimensions can be reviewed first. Non-standard sizes can be produced from a confirmed drawing, groove specification or approved sample.
Send the Operating Conditions Before Requesting a Price
Include the fluid, temperature, pressure, motion, O-ring size or drawing, hardness, compliance requirement and order quantity. Clear application data reduces material changes, sample revisions and repeated quotation work.
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