Rubber Material Engineering Guide
HNBR: Properties, Applications & Selection Guide
Hydrogenated nitrile butadiene rubber (HNBR) extends the oil resistance of nitrile rubber with improved heat, oxidation, ozone and mechanical performance. It is used for demanding seals, gaskets, belts, hoses, diaphragms and molded components in automotive, industrial, refrigeration and oil-and-gas systems. HNBR is still a compound-dependent material family: ACN content, degree of hydrogenation, cure system, fluid, temperature, pressure and motion must be reviewed together.
HNBR Fundamentals
What Is HNBR Rubber?
HNBR is made by selectively hydrogenating the carbon-carbon double bonds in nitrile butadiene rubber. Reducing this unsaturation improves resistance to heat, oxygen and ozone while retaining the nitrile groups that support resistance to many oils, lubricants and hydrocarbon fluids.
Hydrogenation changes NBR substantially, but HNBR is not one fixed recipe. Acrylonitrile content, residual double-bond level, molecular weight, fillers, plasticizers, stabilizers, reinforcing agents and cure package all influence the cured compound. Fully saturated and partially saturated polymer grades may also require different cure-system decisions.
This distinction matters in purchasing. Two parts described as “HNBR 70 Shore A” can differ in low-temperature flexibility, oil swell, compression set, heat aging, abrasion, rapid-gas-decompression resistance and regulatory status. The finished compound and application test—not the family name alone—must support the specification.
HNBR is usually a strong candidate when
- Oil resistance must be combined with higher heat and oxidation resistance than standard NBR.
- The component operates in automotive, refrigeration, hydraulic, compressor or industrial equipment.
- Ozone, hot air, dynamic wear or long-term mechanical retention is important.
- A validated HNBR grade exists for the exact fluid, pressure and temperature profile.
HNBR needs another look when
- The lowest operating temperature exceeds the selected grade's flexibility or sealing limit.
- The medium contains aggressive ketones, esters, polar solvents or an unknown additive package.
- Steam, glycol, refrigerant, sour gas or biofuel compatibility is assumed without exact-fluid data.
- The required temperature or chemical exposure calls for FKM, FEPM, FFKM or another specialist material.
Performance Profile
What Are the Key Properties of HNBR Rubber?
HNBR is best understood as a heat- and aging-resistant nitrile elastomer family. Compared with standard NBR, hydrogenation generally improves thermal stability, oxidation and ozone resistance while supporting strong mechanical and abrasion performance. Fluid resistance and cold flexibility remain strongly grade- and compound-dependent.
Oil & Lubricant Resistance
HNBR retains useful resistance to many mineral oils, lubricants and greases. The exact ACN level, formulation, additives and operating temperature determine actual swelling.
Heat & Oxidation
Hydrogenation improves resistance to hot-air aging and oxidative degradation compared with conventional NBR. Continuous and peak limits still require compound data.
Ozone & Weathering
HNBR provides substantially better ozone and environmental aging resistance than standard NBR, especially when the degree of saturation and compound protection match the duty.
Mechanical & Abrasion
Selected HNBR compounds provide high strength, tear and abrasion performance for dynamic seals, belts and demanding mechanical components.
Compression Set
Low-set HNBR compounds can be formulated for elevated-temperature sealing, but cure state, time, compression, medium and part geometry determine the result.
Low-Temperature Flexibility
Low-temperature HNBR grades are available, but greater fluid resistance or reinforcement can reduce cold flexibility. Define the required sealing function at minimum temperature.
Polymer & Compound Design
How Do ACN Content and Hydrogenation Change HNBR Grades?
Two polymer variables are central to HNBR selection. ACN content influences polarity, oil swell and low-temperature flexibility, while the degree of hydrogenation controls how much unsaturation remains available for aging and crosslinking. Neither variable can be evaluated in isolation from the finished compound.
Commercial HNBR families include fully saturated grades for peroxide crosslinking, partially saturated grades that can support peroxide or sulfur chemistry, low-temperature grades, low-viscosity processing grades and specialty reinforced systems. Purchasing requirements should focus on measurable compound and finished-part performance unless a qualified polymer or compound is mandatory.
| HNBR Variable | General Direction | Why It Matters |
|---|---|---|
| Lower ACN | Generally supports better low-temperature flexibility, with greater swell risk in some hydrocarbon media | Useful when cold sealing is more critical than minimum oil or fuel swell. |
| Higher ACN | Generally improves resistance to swelling in non-polar oils and hydrocarbon fluids | Can reduce low-temperature flexibility, so the trade-off must be validated. |
| Higher hydrogenation | Reduces residual double bonds and generally improves heat, oxidation and ozone resistance | Influences aging performance and the feasible cure system. |
| Partially saturated grade | Retains more residual unsaturation and may permit sulfur or peroxide crosslinking | Provides formulation flexibility but is not interchangeable with a fully saturated grade. |
| Mooney viscosity / molecular structure | Changes mixing, extrusion, mold flow, green strength and reinforcement dispersion | Must suit the selected manufacturing route and part geometry. |
| Fillers / plasticizers | Adjust hardness, modulus, strength, cold flexibility, swell and processing | Explains why equal-hardness HNBR compounds can perform differently. |
| Reinforced HNBR systems | Can raise modulus, strength and wear performance for specialized duties | May change flexibility, processing and sealing behavior; validate the finished part. |
| Cure package | Changes compression set, heat aging, mechanical balance and production behavior | Must match saturation level, temperature, fluid, bonding and compliance needs. |
Engineering note: ACN content and hydrogenation help explain HNBR behavior, but the cured compound and finished part—not the raw polymer alone—must meet the project specification.
Vulcanization
Peroxide-Cured vs. Sulfur-Cured HNBR: What Changes?
Peroxide curing is widely associated with fully saturated HNBR grades and demanding heat-aging or compression-set targets. Partially saturated HNBR grades retain more reactive double bonds and may be designed for sulfur or peroxide crosslinking. The cure route must match the polymer grade and finished-part requirement.
| Selection Factor | Peroxide-Cured HNBR | Sulfur-Cured HNBR |
|---|---|---|
| Polymer compatibility | Common route for fully saturated HNBR grades and also available for suitable partially saturated grades. | Requires an HNBR grade with sufficient residual unsaturation and a compatible sulfur cure package. |
| Heat aging | Often selected when thermal stability and retention of sealing properties are priorities. | Can provide useful performance within the validated limit of the specific compound. |
| Compression set | Can be optimized for elevated-temperature compression behavior; actual values remain formulation-specific. | Mechanical balance and set depend on sulfur system, crosslink structure and cure state. |
| Mechanical balance | May favor thermal and set performance while fillers and coagents tune strength and modulus. | Can be formulated for useful tensile, elongation, fatigue and processing behavior. |
| Rubber-to-metal bonding | Requires an adhesive and surface-treatment system validated for the peroxide-cured compound. | Requires a bonding system compatible with the sulfur-cured HNBR and substrate. |
| Production control | Mixing cleanliness, coagent dispersion, mold temperature and cure state must be controlled. | Scorch safety, cure speed, blooming risk and post-cure requirements must be reviewed. |
Durometer Selection
What HNBR Hardness Should You Choose?
Published commercial HNBR sealing portfolios include compounds from about 50 to 95 Shore A, but this is evidence of market availability rather than a universal recommendation. The correct hardness depends on seal geometry, pressure, extrusion gap, motion, assembly force, temperature and fluid exposure.
Hardness affects conformity, compression force, deformation and extrusion resistance. It does not by itself define oil resistance, low-temperature capability, compression set, tensile strength, rapid-gas-decompression resistance or service life. An HNBR compound must be selected as a complete formulation.
Lower Hardness
Can improve conformity and reduce closure force, but pressure, gland fill and extrusion gap must prevent excessive deformation or nibbling.
Medium Hardness
Often considered for general O-rings, gaskets and molded seals where flexibility, handling, compression and mechanical support must be balanced.
Higher Hardness
Can improve resistance to extrusion and deformation under pressure, but raises assembly force and may reduce conformity or cold flexibility.
Specify the hardness method, nominal value and tolerance on the approved compound specification. ISO 48-4 or ASTM D2240 are commonly used for Shore durometer testing of vulcanized rubber.
Thermal Limits
What Temperature Range Can HNBR Rubber Handle?
Commercial sealing guidance commonly places HNBR around -30°C to +140°C in compatible mineral oils and greases, with special low-temperature grades extending lower and short exposures sometimes reaching about +160°C. These figures describe published product portfolios, not a guaranteed range for every HNBR compound or finished part.
Usable temperature depends on ACN content, hydrogenation, plasticizer, cure system, time, fluid, pressure, motion and the required function. A seal that survives storage at a stated minimum temperature may not remain flexible enough to seal dynamically at that temperature.
Low Temperature
Define storage, start-up and operating requirements separately. Low-temperature HNBR grades can improve flexibility, but oil swell and mechanical trade-offs must be checked.
Continuous Heat
Long exposure controls oxidation, hardening, compression set and retained strength. Use compound-specific aging and fluid data at the real continuous temperature.
Peak Temperature
State peak value, duration and frequency. A short published peak must not be converted into a continuous-service rating.
Hot Fluid Exposure
Fluid additives, refrigerants, gases and oils can accelerate swelling or property loss at elevated temperature. Validate the actual medium at temperature.
Media Compatibility
What Oils, Fuels, Refrigerants and Chemicals Is HNBR Compatible With?
HNBR is widely considered for mineral oils, lubricants, petroleum-based hydraulic fluids and selected fuels or refrigerants when higher heat and aging resistance than NBR is required. “HNBR compatible” is never enough for a critical application: fluid grade, additives, concentration, temperature, pressure and exposure time must be identified.
| Medium / Environment | General HNBR Direction | Engineering Note |
|---|---|---|
| Mineral oils / lubricating oils | Generally strong | Core HNBR application; verify oil type, viscosity, additive package and temperature. |
| Petroleum greases / hydraulic fluids | Often suitable | Common industrial and automotive service when the selected compound is validated. |
| Ozone / hot air / outdoor weather | Improved vs. NBR | Hydrogenation gives much better environmental aging resistance, but compound and strain still matter. |
| Gasoline / diesel / hydrocarbon fuels | Compound-specific | ACN level and fuel composition influence swell; oxygenates and bio-components require exact-fluid review. |
| Refrigerants and compressor oils | Application-specific | Selected HNBR compounds are used in refrigeration systems; refrigerant, oil and moisture must be reviewed together. |
| Water-glycol / coolants | Compound-specific | Some HNBR compounds are formulated for coolant service; additives and hot aging determine suitability. |
| Hot water / steam | Requires review | Performance varies significantly by formulation and temperature; do not assume general steam resistance. |
| Ketones / esters / strong polar solvents | Often unsuitable | Swelling or property loss may be severe; check the exact solvent and alternative elastomers. |
| Concentrated acids / strong oxidizers | Usually not first choice | Concentration and heat can attack the compound; review a more chemically resistant material. |
| Glycol brake fluids | Usually not first choice | EPDM is commonly evaluated for glycol-based brake-fluid service; confirm the exact specification. |
| Sour gas / high-pressure gas / CO₂ | Special compounds only | Define gas, pressure and decompression; ISO 23936-2, NORSOK M-710 or API 6A may apply. |
Material Selection
HNBR vs. NBR, FKM and EPDM: Which Should You Use?
HNBR is commonly chosen when standard NBR provides the right oil-resistance direction but lacks enough heat, oxidation, ozone or mechanical durability. FKM is often reviewed for higher temperatures and broader fuel or chemical resistance, while EPDM is generally stronger for water, steam, glycol and outdoor duties that do not involve petroleum oil.
| Selection Factor | HNBR | NBR | FKM | EPDM |
|---|---|---|---|---|
| Mineral oil / grease | Strong | Strong | Strong | Generally poor |
| Heat and oxidation | Improved over NBR | Moderate | Generally stronger | Strong in compatible media |
| Ozone / weather | Strong | Limited | Strong | Excellent |
| Low-temperature flexibility | Grade-specific; special grades available | Often good in low-ACN grades | Type-specific; low-temperature grades available | Often good |
| Abrasion / mechanical strength | Often strong | Useful | Compound-specific | Compound-specific |
| Fuels / refrigerants | Exact compound and fluid required | Exact compound and fluid required | Often broader, still type-specific | Usually not first choice for petroleum fuels |
| Relative material cost | Usually above NBR | Often economical | Usually above HNBR | Often economical to moderate |
This comparison is directional. Final material selection requires the exact compound, fluid, temperature, pressure, motion, expected life and applicable specification.
Industrial Applications
Where Is HNBR Rubber Used?
HNBR is used where heat, oil, oxidation and mechanical demand exceed the practical window of standard NBR. Common product forms include O-rings, shaft seals, gaskets, diaphragms, hoses, belts, boots, bonded components and custom molded parts. Every application still needs a compound matched to its exact medium and duty cycle.
Automotive Powertrain & Fluids
Selected seals, gaskets, boots and hose components for engine, transmission, fuel, coolant and lubrication systems where the exact fluid and thermal cycle are validated.
Refrigeration & Air Conditioning
O-rings and sealing components designed for defined refrigerant, compressor oil, moisture, temperature and pressure conditions.
Oil & Gas Equipment
Special HNBR compounds for downhole, wellhead, valve and high-pressure sealing may require sour-fluid, rapid-gas-decompression and customer-standard qualification.
Hydraulics & Pneumatics
Rod, piston, rotary and static seals for compatible hydraulic fluids or lubricated gas systems operating above standard NBR's aging limit.
Belts & Dynamic Components
HNBR is used in selected timing belts, drive belts, rollers and wear components that need heat, oil, fatigue and mechanical retention.
Pumps, Valves & Compressors
Diaphragms, gaskets, valve seals and molded components for defined oils, gases, refrigerants or process fluids under controlled temperature and pressure.
Compression Set & Failure Analysis
Why Do HNBR Seals Fail, Swell, Harden or Blister?
HNBR failures are rarely explained by hardness alone. Heat, oxygen, fluid chemistry, pressure, gas absorption, rapid decompression, friction, compression, cure state, installation damage and geometry can interact. A useful investigation connects the observed damage to the actual duty cycle and compound batch.
Hydrogenation improves aging resistance, but it does not make HNBR immune to excessive temperature, incompatible media, loss of plasticizer, extrusion, abrasion or explosive decompression. Failure analysis should include service history, part location, pressure changes, returned-part condition and relevant material tests.
| Observed Condition | Possible Causes | What to Check |
|---|---|---|
| Permanent flattening / leakage | Compression set, excessive heat, under-cure, over-compression or long dwell | Compound data, cure state, squeeze, gland fill, temperature history and recovery condition. |
| Volume swell / softening | Incompatible oil, fuel, refrigerant, solvent or additive package | Exact fluid, ACN direction, exposure temperature, time and ISO 1817 / ASTM D471 results. |
| Hardening / cracking | Thermal oxidation, excessive continuous heat, chemical extraction or over-aging | Air and fluid temperature history, retained hardness, tensile and elongation. |
| Blisters / internal splits | Rapid gas decompression after high-pressure gas absorption | Gas composition, pressure, exposure time, decompression rate, cross-section and qualified compound. |
| Extruded or nibbled edge | Excessive clearance, pressure, soft compound, thermal expansion or missing back-up support | Gap, pressure cycle, hardness, gland fill, swelling and back-up-ring design. |
| Polished or worn surface | Friction, inadequate lubrication, rough counterface, contamination or misalignment | Motion, speed, surface finish, lubrication, temperature rise and wear debris. |
| Low-temperature or assembly leakage | Compound below flexibility limit, insufficient squeeze, sharp edges, twist or installation damage | Minimum functional temperature, groove, lead-in chamfer, installation method and seal condition. |
Manufacturing
How Are Custom HNBR Rubber Parts Manufactured?
Custom HNBR parts can be compression molded, transfer molded, injection molded, extruded, calendered, fabric reinforced or bonded to metal. The manufacturing route depends on geometry, compound viscosity, cure system, reinforcement, tolerance, surface requirements, quantity and validation plan.
- Application reviewConfirm fluid, temperature, pressure, gas exposure, motion, environment, compliance and expected life.
- Compound definitionSelect ACN and hydrogenation direction, hardness, cure system and required aging or RGD properties.
- Tooling / process reviewChoose compression, transfer, injection, extrusion, reinforcement or bonding based on design and volume.
- Sample validationCheck dimensions, appearance, fit and the agreed material, fluid, pressure or functional tests.
- Production controlControl compound batch, cure, cavities, post-cure, dimensions, appearance and traceability.
Molded HNBR
Suitable for O-rings, gaskets, diaphragms, boots, bushings, seals and complex molded parts. Tooling and process depend on geometry and production volume.
Extruded HNBR
Used for selected profiles, cords, hose layers and tubing. Cross-sectional tolerance, cut length, surface and joining requirements should be specified.
Fabric-Reinforced HNBR
Fabric can reinforce diaphragms, hoses and flexible pressure parts where controlled deformation, strength and fatigue resistance are required.
Rubber-to-Metal HNBR
Bonded parts require compatible substrate preparation, adhesive, HNBR formulation and cure process. Bond-performance requirements need definition.
Belts & Composite Parts
HNBR can be used in reinforced belt and composite constructions where rubber, cords, fabric and adhesion system must be engineered together.
Secondary Operations
Post-curing, trimming, grinding, cutting, marking, inspection and packaging should be defined when they affect performance or cleanliness.
Dimensions & Design
What Tolerances Can Be Achieved on HNBR Parts?
There is no universal tolerance for HNBR rubber. Achievable tolerances depend on part size, geometry, mold-dependent versus mold-independent dimensions, compound shrinkage, tool construction, inserts, flash location, process and measurement method.
ISO 3302-1:2014 is a common dimensional-tolerance reference for molded, extruded and calendared solid rubber products. Precision O-rings and similar toroidal sealing rings are normally specified under product-specific standards such as ISO 3601. The correct tolerance system must be agreed before tooling.
Define Critical Characteristics
Identify sealing diameters, wall thickness, compression height, groove interfaces, insert positions and dimensions that control function.
Avoid Unnecessary Tight Tolerances
Tighter tolerances increase tooling, measurement and process-control demands. Apply precision only where it protects fit, sealing or assembly.
Agree Flash & Surface Criteria
Parting line, flash, gate, trimming, grinding, post-cure appearance and cosmetic limits should be defined separately from dimensions.
Confirm Measurement Method
Soft elastomers deform under measurement force. Define conditioning, datums, fixtures and measurement method for compression-sensitive dimensions.
Validation & Quality
Which Tests Should Be Specified for HNBR Rubber?
A useful HNBR test plan starts with the dominant failure risk. Hardness and tensile data alone are not enough if the seal must retain force in hot oil, survive refrigerant exposure, resist wear, operate at low temperature or withstand high-pressure gas decompression.
| Property / Risk | Common Test Reference | What to Define |
|---|---|---|
| Hardness | ISO 48-4 / ASTM D2240 | Scale, nominal value, tolerance, conditioning and test-piece requirement. |
| Tensile strength / elongation | ISO 37 / ASTM D412 | Minimum values, specimen type and whether results are original or aged. |
| Compression set | ISO 815-1 / ASTM D395 | Compression, time, temperature, recovery method and maximum result. |
| Heat aging | ISO 188 / ASTM D573 | Temperature, duration and permitted hardness, tensile or elongation change. |
| Liquid / oil / fuel resistance | ISO 1817:2024 / ASTM D471 | Exact fluid, temperature, duration and permitted mass, volume or property change. |
| Ozone resistance | ISO 1431-1:2024 / ASTM D1149 | Ozone concentration, strain, temperature, duration and cracking criteria. |
| Low-temperature behavior | ISO 2921 / ASTM D1329 or agreed method | Retraction or flexibility criterion, conditioning and actual functional temperature. |
| Rapid gas decompression / sour service | ISO 23936-2, NORSOK M-710, API 6A or customer method | Gas, liquid, pressure, temperature, exposure, decompression and acceptance criteria. |
| Dimensions / application function | Approved drawing and customer-specific validation | Critical dimensions, leakage, pressure, friction, cycle, fatigue, life and inspection plan. |
Test standards and editions should be agreed in the purchase specification. Availability of any specific test, report, approval or third-party laboratory service is to be confirmed for the project.
Regulatory & Documentation
Does HNBR Automatically Meet FDA, NSF, NORSOK or Other Requirements?
No. HNBR is a polymer-family name, not a compliance statement. Specific compounds may be developed, tested or approved for food contact, drinking water, automotive, refrigeration, medical, oil-and-gas or environmental requirements, but generic HNBR does not automatically satisfy any named standard.
If the project requires FDA food-contact requirements, NSF/ANSI 51 or 61, RoHS, REACH, an automotive or refrigerant specification, NORSOK M-710, ISO 23936-2, API 6A, PPAP documentation or another customer standard, state the exact requirement at RFQ stage. Compound availability, color, test scope and documentation must be confirmed before approval.
Purchasing Guide
What Information Should You Send for an HNBR RFQ?
A quote can look complete but still carry material risk if it contains only “HNBR, black, 70 Shore A.” For a demanding seal, the exact fluid, temperature, pressure cycle, gas exposure and required validation are as important as hardness and geometry.
| RFQ Item | Information to Provide | Why It Matters |
|---|---|---|
| Geometry | 2D drawing, 3D model or physical sample; identify revision | Defines tooling, parting, shrinkage, dimensional risk and inspection. |
| Function | O-ring, gasket, shaft seal, diaphragm, hose, belt, bonded seal, boot or other component | Changes the important mechanical and validation requirements. |
| Medium | Exact oil, fuel, refrigerant, coolant, gas or chemical name, grade and additives | Determines ACN direction, swelling risk and whether HNBR is appropriate. |
| Temperature | Minimum functional, continuous maximum, peak maximum and peak duration | Controls cold flexibility, aging, hardening and compression-set risk. |
| Pressure / vacuum | Normal and maximum pressure, pressure direction and cycle | Affects hardness, extrusion, reinforcement, seal geometry and validation. |
| Gas / decompression | Gas composition, exposure time, decompression rate and cycle frequency | Required to assess permeation and rapid-gas-decompression risk. |
| Motion | Static, reciprocating, rotating, flexing or repeated compression | Changes wear, friction, fatigue and heat generation. |
| Material target | Approved HNBR compound or grade if fixed; hardness, color and cure system if defined | Separates mandatory requirements from supplier recommendations. |
| Aging limits | Permitted volume, mass, hardness, tensile or elongation change | Turns “heat and oil resistant” into measurable acceptance requirements. |
| Tolerances | Critical dimensions, tolerance standard and inspection method | Controls tooling, process capability and measurement cost. |
| Compliance | Exact regulation, customer standard, approval or report required | Prevents generic HNBR from being mistaken for a qualified compound. |
| Testing | Media aging, pressure, leak, RGD, fatigue, PPAP or customer validation | Allows validation scope, cost and timing to be reviewed before production. |
| Quantity / packaging | Prototype, order and annual quantity; label, lot and cleanliness requirements | Influences tooling, cavities, manufacturing route, traceability and delivery format. |
HNBR FAQ
Frequently Asked Questions About HNBR Rubber
These answers are material-family guidance. Final performance should always be confirmed against the exact HNBR compound and service conditions.
What does HNBR stand for?
HNBR stands for hydrogenated nitrile butadiene rubber. It is also called hydrogenated nitrile or HSN. These names describe a polymer family, not one fixed compound specification.
How is HNBR different from standard NBR?
HNBR is produced by selectively hydrogenating the carbon-carbon double bonds in NBR. This generally improves heat, oxidation and ozone resistance while retaining useful oil resistance. HNBR is usually more costly, and fluid and low-temperature performance remain grade-specific.
Is HNBR resistant to oil and grease?
Yes, resistance to many mineral oils, lubricants and greases is a major HNBR strength. Actual suitability depends on ACN content, compound formulation, oil additives, temperature and exposure time.
What temperature can HNBR withstand?
Commercial sealing guidance commonly cites about -30°C to +140°C in compatible mineral oils and greases. Special grades can extend lower, and some portfolios publish short exposures around +160°C. The exact compound, medium, time and function determine the usable range.
Is HNBR suitable for outdoor and ozone exposure?
HNBR generally provides much better ozone, oxidation and weathering resistance than standard NBR. Actual durability still depends on hydrogenation level, compound protection, temperature, strain and exposure duration.
Can HNBR be used with refrigerants?
Selected HNBR compounds are used in refrigeration and air-conditioning systems, but compatibility must cover the exact refrigerant, compressor oil, moisture, temperature and pressure. A generic HNBR designation is not sufficient.
Can HNBR be used with gasoline, diesel or biofuels?
Selected HNBR compounds can be used with certain hydrocarbon fuels. ACN content, aromatic content, oxygenates, bio-components, additives and temperature influence swell, so the exact fuel blend must be reviewed.
Is HNBR suitable for steam or hot water?
Steam and hot-water performance varies considerably by HNBR formulation and temperature. Do not assume general suitability; compare compound-specific aging data and consider EPDM, FEPM or another family when the medium demands it.
What Shore hardness is HNBR?
HNBR is not one fixed hardness. Published commercial sealing compounds include examples from roughly 50 to 95 Shore A. The correct value depends on geometry, pressure, extrusion gap, compression, motion, assembly and temperature.
Is all HNBR peroxide cured?
No. Peroxide curing is widely used for fully saturated HNBR and demanding heat-aging targets. Partially saturated HNBR grades can also support sulfur cure systems. The polymer grade and performance requirement determine the feasible route.
HNBR or FKM: which should I choose?
HNBR often provides strong mechanical, abrasion and oil performance with improved heat resistance over NBR. FKM is commonly evaluated for higher temperatures or broader fuel and chemical resistance. Compare the exact fluid, low-temperature need, dynamic duty and cost.
HNBR or EPDM: which is better?
HNBR is usually the stronger starting point for petroleum oils, lubricants and demanding mechanical duties. EPDM is usually stronger for water, steam, glycol and outdoor exposure where petroleum oil is absent. The main medium normally decides the direction.
Can HNBR resist rapid gas decompression?
Special HNBR compounds are available for rapid-gas-decompression service, but generic HNBR is not automatically resistant. Gas composition, pressure, temperature, exposure time, decompression rate, seal size and the named qualification method must be defined.
Does HNBR automatically meet NORSOK M-710 or ISO 23936-2?
No. Only specific compounds tested against the relevant conditions and documentation can support those requirements. State the exact standard, edition, medium, temperature, pressure and report requirement before material approval.
What information is needed to quote a custom HNBR part?
Send the drawing, 3D model or physical sample together with the exact fluid or gas, minimum and maximum temperature, pressure and decompression cycle, motion, hardness, tolerance, compliance, testing and quantity requirements.
Custom HNBR Components
Have an HNBR seal, gasket, diaphragm or molded part to develop?
Send the available drawing or sample information together with the exact working fluid or gas, temperature, pressure cycle, hardness target and expected quantity. We can review the HNBR material direction, manufacturing feasibility and the technical information still needed before quotation.
