How To Select The Seals For Hydraulic Cartridge Valves - China

How to select the Seals for Different Hydraulic Screw-in Cartridge Valves? Chinese Hydraulic Screw-in Cartridge valve manufacturer AAK often receives various questions from overseas customers, some of which even come from college students conducting academic research.

Today, we will once again introduce the main materials used for seals in hydraulic screw-in cartridge valves, as well as their respective characteristics: 1 - Rubber Sealing Materials

1) Nitrile rubber (NBR)

- Excellent oil resistance, suitable for conventional hydraulic oil environments, with a working temperature range of -40 ℃ to+120 ℃.

- Mainly used in static sealing scenarios, such as O-rings and some combination seals

2) Fluororubber (FKM)

- High temperature resistance (up to 200 ℃), chemical corrosion resistance, suitable for hydraulic oil containing phosphate esters or highly corrosive media.

- Commonly used in high-pressure systems or extreme temperature environments.

3) Silicone rubber (VMQ)

- Outstanding cold resistance (-70 ℃ to+200 ℃), but low mechanical strength, only suitable for static sealing 2 - Polymer Sealing Materials

1) Polytetrafluoroethylene (PTFE)

- Extremely low friction coefficient, good self-lubricating properties, strong corrosion resistance, suitable for high-speed or chemically corrosive environments.

- Often used as a filling material in conjunction with rubber, or in combination with seals (such as Glay rings, seals).

2) Polyurethane (PU)

- High wear resistance and anti extrusion strength, suitable for high-pressure reciprocating motion seals (such as Y-shaped rings, U-shaped rings), working temperature -30 ℃ to+100 ℃.

3) Nylon (PA)

- Oil resistant and wear-resistant, used for non direct sealing components such as guide rings and support rings, with a working temperature of -40 ℃ to+120 ℃.

3 - Metal Sealing Materials

Stainless steel/copper alloy

- Used for extreme high pressure (>32MPa) or high temperature (>450 ℃) scenarios, achieving metal to metal sealing through precision machining.

4 - Composite Sealing Materials

Clip on rubber+rubber (lace ring) or PTFE+rubber (Glay ring/Steller seal)

- Combining the elasticity of rubber with the wear resistance of PTFE/sandwich material, suitable for high-pressure dynamic sealing (such as valve spool and valve cage).

Selection Suggestions

- Normal working conditions: Priority should be given to using nitrile rubber or polyurethane.

- High temperature/corrosive environment: Fluorine rubber or PTFE composite materials are better.

- Ultra high pressure scenario: requires metal seals or combined sealing structures.

AAK HYDRAULIC VALVES (844) 2025-03-17

Company Contact:

• Posted By: AAK Industry CO., LTD

• Phone: +8657483008115

• Address: Bona Business Building, No. 456 Taikang Middle Road,, Yinzhou, Ningbo, China, Ningbo , Zhejiang , China

• Email:

• Website: https://www.aakindustry.com/

• Business Description: Focused on the Development and Manufacturing of Hydraulic Valves since 2006, in Ningbo China
  
  Since its establishment 12 years ago, 6 first-line international brand importers have placed orders with AAK for 5 consecutive years, with a re-peat order rate of 62%.
  
  Exported to more than 20 countries, AAK Hydraulic Valves used on "AIRCRAFT" have been supplied to Russian customers.
  
  68%+ of the high precision hydraulic valves exported from Ningbo Port come from AAK hydraulic valves.