How to Choose the Right Rubber Fitting Material

Selecting the right rubber fitting material based on the application environment is crucial, as it must match the operating conditions such as temperature, medium, pressure, and external environment. Materials with strong adaptability, such as EPDM (ethylene propylene diene monomer), NBR (nitrile butadiene rubber), and FKM (fluororubber), are recommended as a priority.

Selection by Temperature Environment: Ensuring Rubber Does Not Fail at Extreme Temperatures

The temperature resistance of rubber directly affects its elasticity and lifespan. Material selection must cover the actual operating temperature range and allow for a safety margin.

High Temperature Environment (>80℃)
Suitable for steam pipelines, engine cooling systems, etc.

Recommended Materials: Fluororubber (FKM) can withstand temperatures above 200℃; EPDM is suitable for hot water and steam systems ≤150℃.

Avoidance Tip: Ordinary NBR is prone to hardening and cracking above 120℃ and is not suitable for long-term high-temperature conditions.

Low-temperature environments (<-20℃): Commonly used in outdoor equipment and cold chain transportation systems in cold regions.

Recommended materials: Cold-resistant neoprene rubber (CR) or specially formulated silicone rubber (SI), which can maintain flexibility below -40℃.

Notes: Natural rubber becomes brittle at low temperatures, its compensating ability decreases, and there is a risk of bursting.

Selection by media type: Preventing swelling, corrosion, or chemical reactions. The conveying medium is the core factor determining the inner layer rubber material. Incorrect material selection can lead to pipe expansion, cracking, or even leakage.

Oil-based media (fuel, lubricating oil, hydraulic oil)

Preferred material: Nitrile rubber (NBR): The higher the acrylonitrile content, the stronger the oil resistance. Widely used in automotive power systems and industrial hydraulic equipment.

High-end alternative: Fluororubber (FKM): Excellent oil resistance and high-temperature resistance, suitable for high-reliability applications such as aerospace and precision machinery. Acid and Alkali Solutions (pH < 5 or pH > 9)

Recommended: Ethylene Propylene Diene Monomer (EPDM) rubber: Excellent resistance to strong acids, strong alkalis, and ozone, suitable for chemical plants and wastewater treatment systems.

Extreme Corrosive Environments: PTFE (Polytetrafluoroethylene) lined composite pipes can be used, resistant to almost all chemical corrosion.

Steam and Hot Water

EPDM or Silicone Rubber (SI) Rubber is preferred: Good heat aging resistance and steam permeation resistance, commonly used in building heating and industrial boiler systems.

Air and Inert Gases

General-purpose natural rubber (NR) or styrene-butadiene rubber (SBR) can meet the requirements, offering low cost and good sealing performance.