Oil Resistant Nitrile O-Rings with 70-90 Shore A Hardness and Custom Sizes for Industrial Sealing

Product Overview
 

High-Performance Nitrile (NBR) O-Rings | 70-90 Shore A
 
These black NBR (Buna-N) O-rings are offered in 70-90 Shore A hardness options for industrial sealing and maintenance enquiries. Specify the inside diameter (ID), cross-section (CS), dimensional tolerances and chosen hardness so the ring can be matched to the actual groove and service fluid.
 
For MRO replacement, provide the existing part number, AS568 dash size or dimensioned sample drawing. For a new design, include gland dimensions, static or moving duty, pressure, temperature and the exact oil or fuel composition. Confirm the compound and fit before installation.

The Advantages of Nitrile (NBR/Buna-N) Material
Nitrile Butadiene Rubber is commonly called NBR or Buna-N. These names identify the polymer family; hardness, mechanical properties and fluid compatibility depend on the particular formulation. Review the following selection points for the intended service:

• Oil-Service Selection: NBR is an option for selected petroleum oil applications. Identify the oil grade, fuel blend and additives for compound compatibility review.

• Mechanical Properties: Agree tensile, elongation or wear requirements and the test method where these are needed for the application.

• Compression Set: Temperature, squeeze and exposure time affect recovery and sealing performance. Specify any required compression-set test criteria.

• Hardness Options: Select hardness together with groove clearance, movement and pressure. Hardness alone does not establish a pressure rating.

Multi-Purpose Applications

 
Application enquiries include the following equipment; suitability depends on the selected compound and seal design:

• General Machinery: Gearboxes, pumps, compressors, and conveyors.
• Pneumatic Systems: Air cylinders, valves, and pneumatic tools.
• Fluid Power: Standard hydraulic connections and fluid transfer components.
• MRO Supply: Essential for repair kits in manufacturing plants and automotive workshops.
• Plumbing & HVAC: Confirm water treatment chemicals, refrigerant and lubricant compatibility for the intended system.

Material Comparison: NBR vs. Others

 
NBR vs. FKM (Fluorocarbon):
NBR and FKM are different material families. Compare the exact fluid, minimum and maximum temperature, exposure duration and required low-temperature flexibility against compound data rather than applying one universal temperature range.

 
NBR vs. EPDM (Ethylene Propylene):
EPDM is commonly considered for weather exposure and selected water-service requirements, while NBR is considered for many oil-service applications. Petroleum-fluid compatibility must be reviewed for the actual formulation; neither material is a universal substitute for the other.

Product Description

	Material: Nitrile Butadiene Rubber (NBR / Buna-N)
	Color: Black
	Hardness: 70-90 Shore A options; confirm target value and tolerance
	Tensile Strength: Confirm the selected compound specification and test requirement

Company Profile

Established in 2013, Shanghai Qinuo Industry (SHQN) specializes in the engineering and manufacturing of high-performance rubber seals for the Oil & Gas industry.
 

Our production base in Nantong is equipped with over 30 advanced vulcanizing machines, delivering a monthly capacity of 20 tons (40,000 lbs) across 20+ product categories. Strategically located near Shanghai’s major air and sea ports, we ensure streamlined logistics and reliable global delivery.
 

 
 
Under our registered brands Royal Way® and SHQN®, we remain committed to our core principle: "Quality for Stability, Innovation for Progress." We provide the energy sector with durable, precision-engineered sealing solutions you can depend on.
 
 

FAQ

 
Q: Is there a difference between Buna-N and Nitrile?
A: Buna-N and NBR commonly refer to nitrile rubber. The name alone does not identify an identical formulation: specify compound requirements, hardness and application conditions when ordering.
 
Q: Can I order custom sizes for non-standard equipment?
A: Send ID and CS with tolerances or a dimensioned drawing, required hardness and order quantity. Standard-size availability and any custom tooling requirements are confirmed with the quotation.
 
Q: What is the benefit of 70 Shore A vs. 90 Shore A for general use?
A: A higher Shore A value indicates a harder rubber. Selection depends on the groove, extrusion clearance, pressure, temperature and motion; review backup-ring requirements where applicable. Neither hardness value independently rates the assembly.
 
Q: Where should I NOT use Buna-N O-rings?
A: Review NBR carefully for outdoor ozone or UV exposure, steam, glycol brake fluids, ketones and acid service. Select an alternative only after checking the specific chemical and temperature conditions; EPDM or FKM is not suitable for every one of these media.