NBR O-Rings for Fluid Power Systems: 70 Shore A Buna-N Seals for Leak-Proof Performance in Oil & Gas Rigs.

This listing covers black NBR / Buna-N O-rings with a listed hardness of 70 +/- 5 Shore A for fluid-power equipment replacement. Confirm the size, compound and groove requirements for the actual hydraulic or pneumatic assembly. Hardness alone does not establish pressure suitability or guarantee leak-free operation.

Nitrile Butadiene Rubber (NBR) is a synthetic elastomer used in sealing applications. Select the specific compound against the actual fluid, temperature and movement conditions:

• NBR vs. EPDM: Compare the actual oil, water, steam and outdoor exposure requirements. Neither polymer family name establishes compatibility with every fluid.

• NBR vs. Fluoroelastomer (FKM): Review compound-specific temperature and chemical data before changing materials; confirm fit and acceptance requirements with the equipment specification.

• NBR vs. Silicone: For moving seals, include friction, wear and mechanical-property requirements in the compound review.

70 Shore A NBR Replacement for Fluid Power Assemblies

For a replacement order, provide the AS568 dash number or inside diameter and cross-section, the approved NBR compound, and the 70 +/- 5 Shore A requirement. Add the sealing-groove drawing, fluid designation, continuous and peak temperature, pressure and movement type. Identify any backup ring as a separate assembly item. For pneumatic service, include lubricant and gas details. Confirm dimensional tolerances and inspection requirements before bulk supply.

	Material: Nitrile Butadiene Rubber (NBR / Buna-N)
	Color: Black
	Hardness: Listed 70 +/- 5 Shore A; confirm compound and test requirements
	Tensile Strength: Listed reference 14 to 18 MPa; confirm selected compound and test method

Welcome to Shanghai Qinuo Industry. Backed by our state-of-the-art, ISO 9001:2015 certified manufacturing base—Jiangsu Ruowei Energy Technology—we stand at the forefront of delivering high-performance rubber solutions.

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.

Question 1: Why is 70 Shore A the most common hardness for NBR seals?
Answer: This listing specifies 70 +/- 5 Shore A. The required hardness must match the compound and groove specification; it is not a universal pressure rating.

Question 2: Can I use Buna-N O-rings for outdoor applications?
Answer: Include sunlight, weather and ozone exposure in the material review, together with fluid contact and temperature. Select protection or an alternative compound to suit the complete service conditions.

Question 3: Are these O-rings resistant to gasoline?
Answer: Confirm the exact fuel composition, additives and temperature against the selected compound before use. The NBR designation alone does not confirm suitability for every gasoline or fuel blend.

Question 4: What causes a Buna-N O-ring to fail in a hydraulic system?
Answer: The most common causes are "compression set" (the ring loses its bounce after excessive heat), abrasion from moving parts, or using an incompatible fluid that causes the rubber to swell or shrink.

Question 5: Is Buna-N the same as Nitrile?
Answer: Yes. Buna-N, Nitrile, and NBR all refer to the same synthetic elastomer: Nitrile Butadiene Rubber. These names are used interchangeably across the industry.