Chicago Fitting Manufacturer

Hydraulic fittings can be made from many materials, the most common ones being stainless steel, or brass. The type of assembly or industry application usually determines what material is suitable.

Steel Hydraulic Fittings – these types of fittings are made of steel alloys which means they are far more durable than their plastic counterparts. For instance, carbon steel fittings can withstand temperatures from -53°C up to 260°C.

Stainless Steel Fittings – as the name suggests, these are the stainless steel variant of steel hydraulic fittings. Stainless steel fittings are utilised in situations where they would need to withstand temperatures ranging from -253°C up to 648°C. Their tough nature makes them the choice of fitting for highly corrosive environments.

Brass Fittings – these are not as strong or durable as their stainless steel counterparts. However, they can provide a tight seal that prevents leaks and meet SAE (Society of Automotive Engineers), ISO (International Organization for Standardization), DIN (Deutsches Institute für Normung), and JIS (Japanese Industrial Standards) standards, among others. Brass fittings are rated for temperatures from -53°C up to 204°C, and pressures up to 3,000 psi.

Aluminium Fittings – hydraulic fittings made from aluminium are less common, but do exist and are used in certain applications. They are lighter than steel but are resistant to corrosion. These qualities make them preferable in transportation hydraulics such as the automotive industry.

To properly identify the hydraulic hose fitting for the application, determine the type of fitting, match the port connection with that of the hose, and determine the type of seal and fitting design and size of the thread.

1. Determine the type of fitting – check to see if the fitting is crimped or reusable. Newer equipment and connections are usually crimped.
2. Match the port connection with that of the hose – another important part is to make sure that the port connection matches the one on the hydraulic hose. Refer to the table below.

3. Determine the type of seal – referring to the physical dimensions and technical characteristics, identify whether it is using an O-Ring, a Mated Angle, or a Tapered Thread. Mated Angles are based on straight and parallel thread types, in which the male and female units will form the seal. Tapered Threads will have the threads on the outside if it is a male unit and on the inside if it is female. Lastly, O-Rings (ORFS) will already include the seal.
4. Determine the fitting design and size of the thread – refer to the list below for the most common and widely used hydraulic fittings.
NPT/NPTF – this is the most commonly used type of thread in North America and is recognisable by its tapered inner diameter and outer diameter. This creates a self-sealing fitting.

• BSPT (JIS-PT) – also known as the British Thread Type, is standard fittings adopted internationally for making connections and sealing pipe ends.
• Metric Taper – this is the most commonly used thread type in Europe and is known for its precise cylindrical inner and outer diameters.
  SAE Straight Thread – a thread type known for its reliability and reusability-has excellent sealing due to its 90-durometer O-rings.
  ISO 6149 – this is equipped with a straight thread O-ring port, useful for diagnostic port applications.
• JIS-B2351 – this thread type is primarily used as a hose adapter for equipment manufactured in Japan or Korea. These usually come with BSP threads.
• DIN Metric – Since this thread type uses the German Industrial Standard, they are popular throughout Germany and the majority of Europe.
• BSPP (JIS-PF) – These are BSPP connectors that follow the standard British thread dimensions.
• 4-Bolt Flange – these come in a variety of types, catering to either standard or heavy-duty applications.

The criteria for choosing the right end fittings for hydraulic hoses are size, material, temperature, pressure, application, and assembly. The proper assessment of these criteria is critical to ensure the safety and reliability of the connections. Each of the factors mentioned above are detailed below:
1. Size – when it comes to the size, the important measurements to consider are the internal and external diameters of the hydraulic fittings. The diameters have to be compatible with that of the hydraulic hose. Fittings over or under-sized won’t be sealed properly and cause the connection to fail or leak.
2. Material – different materials have different properties, which affect and determine the compatibility with the fluid. As such, making sure that the fitting is compatible with both the hydraulic fluid and the working environment is critical. Determine both and choose between brass, aluminium, steel, or stainless steel. The most widely-used sealing materials are O-rings made from NBR (Nitrile).
3. Temperature – aside from ensuring that the different materials that make up hydraulic fittings are resistant to the operating temperatures, the type of fittings should also be considered.
4. Pressure – the amount of pressure the hydraulic fitting is subjected to differ across varying industries and applications. Make sure that the fittings are rated for the pressure range required. Operating beyond the rated pressure may cause leaks and even danger to people in the working environment.
5. Application – depending on the industry or application, the fittings could be used for either mixing or distributing. As such, hydraulic fittings such as the T-shape and the cross-shape come into consideration.
6. Assembly – hydraulic systems that require frequent connections and disconnections of the hose or tube should consider quick-connect fittings. For instance, hydraulic compression fittings can also remove the need to weld or solder the fitting. It uses a compression nut that tightens against the ferrule, creating a tight seal.
7. Permanence – Needing a permanent fitting or one that can be removed and changed frequently will affect the fitting style you choose. If this fitting is going to be changed often, a field attachable fitting will work just fine, but if you need something permanent and strong, using a crimping machine to crimp your fitting permanently is the perfect option.
Aside from this criteria, the hydraulic fluids used in the industry should also determine what type of coupling is best. Not all fittings are compatible with all hydraulic fluids. The primary hydraulic fluid types are petroleum-based, water-based or synthetic-based fluids.