Material Combinations
Engineered for Performance in Demanding Environments
Selecting the correct material combination is critical to ensuring reliable performance within pneumatic and fluid transfer systems. Components must operate consistently under defined pressure, temperature and media conditions, particularly in demanding environments such as outdoor, corrosive or high-cycle applications.
For example, a brass body coupling may be chrome-plated to improve corrosion resistance while maintaining cost-efficiency. Alternatively, eBrass® provides a low-lead, dezincification-resistant option for applications requiring compliance and long-term durability. Internal components such as balls and springs are typically manufactured from stainless steel to ensure resistance to corrosion and wear, while seal materials are selected based on temperature range and media compatibility.
These combinations are widely used across manufacturing, automotive, aerospace and marine environments, where reliability and material integrity are essential to system performance.
Coupling Material Options
Material selection is based on operating conditions, required strength, corrosion resistance and application environment.
Brass
Commonly used for compressed air and general industrial applications. Offers good corrosion resistance, moderate strength and compatibility with a wide range of media. Can be plated to improve durability and appearance.
eBrass® - Download PDF
A low-lead brass alternative designed to meet modern compliance requirements including RoHS and REACH. Provides improved resistance to dezincification while maintaining machinability and durability.
Steel
Used in higher-pressure applications where increased strength is required. Typically heat-treated to improve surface hardness and load capacity. Corrosion resistance depends on surface treatment or coating.
Stainless Steel
Suitable for corrosive environments and applications requiring high cleanliness, such as medical, food or marine use. Offers excellent corrosion resistance and strength without the need for plating.
Thermoplastics
Lightweight and resistant to chemicals, moisture and impact. Used in applications where weight reduction or chemical compatibility is required. Can be formulated to provide additional properties such as UV or flame resistance.
Seal Selection
Seal material is critical to ensuring leak-free performance and long service life. Selection is based on temperature range, media compatibility and operating conditions.
EPDM
Excellent resistance to weather, ozone, UV, hot water and steam. Suitable for water-based applications. Not suitable for mineral oils or fuels.
Temperature range: approximately -40°C to +130°C
Rubber
A general-purpose sealing material offering good elasticity, resilience and abrasion resistance. Suitable for a wide range of standard applications.
PTFE
Provides excellent chemical resistance and low friction. Non-stick and suitable for aggressive media where elastomers may not perform well.
Viton / FKM
High-performance fluorocarbon seal material with excellent resistance to heat, oils, fuels, solvents and aggressive chemicals.
Temperature range: approximately -15°C to +200°C
NBR
Excellent resistance to oils, fuels and hydraulic fluids. Commonly used in pneumatic and hydraulic sealing applications.
Temperature range: approximately -20°C to +100°C
Other seal materials are available depending on application requirements.
Surface Treatments & Plating
Kee Connections supplies couplings and plugs in a range of material and surface finish options to suit different operating environments.
Nickel-plated brass is widely used across pneumatic and fluid transfer applications, providing improved corrosion resistance, durability and long-term appearance.
For more demanding environments, selected products are available in nickel-plated steel, chrome-plated brass or stainless steel.
Material and finish selection should be based on the application, operating media and environmental conditions.
For example, marine or corrosive environments may benefit from chrome-plated brass or stainless steel components, while general industrial compressed air systems commonly utilise nickel-plated brass construction.
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READ ARTICLES FROM OUR TECHNICAL BLOG
Understanding Working Pressure and Safety Factor in Quick Release Couplings
Published working pressure is a product limit that must be considered alongside the complete system, media, temperature and duty. A safety factor is a design relationship, not permission to operate above the stated working pressure. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
Single Shut-Off vs Double Shut-Off Quick Release Couplings
The valve arrangement determines what happens to the media when the connection is separated. That affects air loss, fluid spillage, pressure retention, operator behaviour and the suitability of the connection for a particular circuit. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
Replacing an Unknown or Obsolete Quick Release Coupling
When an installed coupling is unknown or obsolete, the safest route is to identify the existing connection systematically before selecting a replacement. Replacing parts on appearance alone can lead to mismatched profiles, incorrect threads or unsuitable materials. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
Choosing Hose Bore and Connection Size for Pneumatic Equipment
Hose selection affects flexibility, pressure drop, handling, abrasion resistance and the way a complete assembly behaves in service. The coupling is only one part of that assembly, so hose bore, material and end connection should be selected together. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
Why Similar-Looking Quick Release Couplings May Not Connect
The plug profile is the geometry that determines whether a plug will physically mate and lock with a coupling. Similar overall sizes do not prove compatibility. Small differences in nose diameter, locking groove position, shoulder geometry and insertion depth can prevent connection or create an unsafe mismatch. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
How to Measure an Existing Quick Release Coupling
Correct identification starts with the connection profile, not the thread on the back of the component. Two couplings can have the same thread size and still use completely different mating plug profiles. For maintenance teams, recording the visible geometry and connection details before ordering reduces trial-and-error replacement work. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing
When to Use a Safety Quick Release Coupling
Connection management is important wherever multiple air, gas or fluid services are present. Identification, keying, colour coding and appropriate safety coupling designs can reduce connection errors and improve maintenance control, but they must form part of a wider engineering procedure. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.
How to Select the Correct Quick Release Coupling
Selecting a quick release coupling is a system decision rather than a choice based on thread size alone. Media, valve arrangement, flow requirement, working pressure, temperature, materials, seal choice, termination and operating environment all need to be considered together. This guide explains the main checks engineers and maintenance teams should make before specifying or replacing the connection.