Precision Black Nitrile O-Rings Buna Seals for Hydraulic Systems

Product Overview

A rubber o ring is a vital sealing component used in virtually every hydraulic and pneumatic system worldwide. It is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts. This compression creates a physical barrier that prevents the leakage of fluids or gases.

This listing covers black NBR / Buna-N O-rings with listed 70-90 Shore A hardness options for hydraulic equipment replacement. Specify one hardness and tolerance, together with the compound reference, seal dimensions and groove drawing. Confirm compatibility with the actual hydraulic fluid and operating conditions.

The Advantages of Nitrile (NBR/Buna-N) Material

Nitrile Butadiene Rubber, commonly known as NBR or Buna-N, is the most widely used elastomer in the seal industry. Its popularity stems from a unique set of characteristics that make it ideal for hydraulic applications:

• Oil-Service Selection: Confirm the selected NBR compound against the exact oil, additives and temperature.
• Mechanical Properties: Specify tensile, tear and wear requirements for the selected compound with appropriate test methods.
• Compression Set: Confirm the required test conditions and acceptance criteria for the compound.
• Material Options: Compare suitable compounds against the complete service requirements before selecting on price.

Material Comparison: NBR vs. Others

NBR vs. FKM (Fluorocarbon):
Compare the specific NBR and FKM compounds against the actual fluid and continuous and peak temperature limits. Family names alone do not establish interchangeable performance.

NBR vs. EPDM (Ethylene Propylene):
Review weather exposure and fluid contact together. Do not substitute EPDM in petroleum-oil service without specific compatibility approval; confirm the appropriate compound for the application.

Product Description

	Material: Nitrile Butadiene Rubber (NBR / Buna-N)
	Color: Black
	Hardness: Listed options 70-90 Shore A; specify one value and tolerance
	Tensile Strength: Listed reference 14 to 18 MPa; confirm compound and test method

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

Question: What is the typical shelf life of a Nitrile (NBR) O-ring?
Answer: Request manufacture-date, packaging, storage and shelf-life guidance for the supplied compound. Inspect seal condition before installation rather than relying on a universal storage period.

Question: Can I use Nitrile O-rings for outdoor applications?
Answer: Standard NBR has moderate resistance to environmental factors. For prolonged outdoor use where exposure to sunlight and ozone is high, the material may develop surface cracks. In such cases, EPDM might be more appropriate.

Question: What is the difference between 70 Shore A and 90 Shore A hardness?
Answer: These are different hardness options. Select the value required by the approved compound and groove specification; hardness alone does not establish a pressure rating.

Question: Is it safe to reuse a Nitrile O-ring after a machine teardown?
Answer: It is not recommended. Once an O-ring has been compressed and exposed to heat and pressure, it takes a permanent set. Reusing it may lead to leaks because the seal cannot return to its original shape to provide a new compression.

Black NBR O-Ring Identification During Hydraulic Maintenance

Use the equipment part reference or seal drawing to identify a replacement. Specify the AS568 dash number or inside diameter and cross-section, selected hardness and tolerance, and approved NBR compound. Include hydraulic-fluid designation, temperature, pressure and movement type. Confirm any backup-ring requirement with the assembly drawing. Black color alone does not identify the compound or size. Record the approved specification for repeat maintenance orders.