Metric hydraulic fittings are used in hydraulic systems to connect hoses, pipes, and tubes to various components such as pumps, valves, and cylinders. These fittings are designed according to metric dimensions and standards, which are widely used in Europe and other parts of the world.
Description: These fittings have a flat sealing surface with an O-ring that ensures a leak-proof seal when connected.
Application: Used in high-pressure hydraulic systems to prevent leaks and maintain integrity under vibration and thermal cycling.
Description: These fittings have a 24-degree conical seat and are commonly used in conjunction with metric threads.
Subtypes: Light Series (L Series): Used for lower pressure applications.
Heavy Series (S Series): Used for higher pressure applications.
Application: Widely used in hydraulic and pneumatic systems in Europe.
Description: These fittings feature a 60-degree conical seat that provides a robust seal.
Application: Commonly used in hydraulic applications that require a secure and reliable connection.
Description: These fittings use parallel threads and typically require a sealing washer or O-ring to achieve a leak-proof seal.
Application: Commonly used in hydraulic systems in Europe and other regions where BSPP standards are prevalent.
Description: These fittings consist of a hollow bolt and spherical union that can rotate.
Application: Used in confined spaces where a flexible connection is required, such as in automotive and machinery hydraulic systems.
JIC metric fittings are most frequently used as hose adapters on equipment manufactured in Japan and Korea. They incorporate a 30° flare and 60° cone connection and typically include BSP threads. Kobelco, a major Japanese OEM construction machinery manufacturer, uses Japanese hydraulic hose and JIS hydraulic fittings.
Komatsu metric 30° flare is one of the most common specialized fittings for a specific OEM mobile equipment manufacturer. While most other OEMs rely on common industry standards, Komatsu has developed this proprietary fitting that is superior in applications on their own equipment.
Metric hydraulic fittings are designed and manufactured according to various standards to ensure compatibility and performance. Some of the common standards include:
DIN (Deutsches Institut für Normung): A German standard that specifies dimensions, tolerances, and testing requirements for hydraulic fittings. For example, the DIN standard focuses on flareless bite fittings, which are critical for high-pressure systems. In short, if a product is DIN certified, it is a sign of quality and international recognition.
ISO (International Organization for Standardization): Provides international standards for hydraulic fittings to ensure global compatibility. For example, ISO : This is another standard for metric fittings related to 24-degree taper fittings; ISO : This standard specializes in metric O-ring face seals; ISO : This standard covers metric ports and stud ends.
Metric hydraulic fittings are manufactured from various materials, each chosen based on the specific requirements of the hydraulic system, including pressure, temperature, fluid compatibility, and environmental conditions. Here are some common materials used in the production of metric hydraulic fittings:
Characteristics: Strong, durable, and cost-effective.
Applications: Widely used in general hydraulic applications, especially where high pressure and high mechanical strength are required.
Surface Treatments: Often coated with zinc, nickel, or chrome to enhance corrosion resistance.
Characteristics: Excellent corrosion resistance, high strength, and durability.
Applications: Ideal for use in harsh environments, including marine, chemical processing, and food industries where corrosion resistance is critical.
Grades: Commonly used grades include 304 and 316 stainless steel, with 316 offering superior corrosion resistance.
Characteristics: Good corrosion resistance, easy to machine, and good thermal conductivity.
Applications: Commonly used in low to medium pressure applications, especially in plumbing, automotive, and refrigeration systems.
Advantages: Resistant to dezincification and suitable for potable water systems.
Simplicity: The metric system is based on the decimal system, which simplifies calculations, measurements, and conversions.
Fewer Sizes: Standardized sizing in metric fittings often means fewer variations and sizes to manage, streamlining inventory and reducing complexity.
Wide Range of Applications: Suitable for various industries, including automotive, aerospace, manufacturing, and agriculture.
Material Options: Available in a variety of materials (steel, stainless steel, brass, aluminum), making them adaptable to different environments and applications.
Performance: Metric fittings are designed to handle high pressure and temperature ranges, making them suitable for demanding hydraulic applications.
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Durability: High-quality materials and precise manufacturing processes ensure long-lasting performance even in harsh conditions.
Advanced Designs: Metric fittings often incorporate advanced sealing mechanisms such as O-ring face seals (ORFS) and 24° cone fittings, providing superior leak prevention and reliability.
Reduced Maintenance: Better sealing reduces the need for frequent maintenance and downtime, improving overall system efficiency.
Corrosion Resistance: Available in materials and coatings that provide excellent corrosion resistance, suitable for harsh and corrosive environments.
Chemical Compatibility: Metric fittings are often compatible with a wide range of hydraulic fluids and chemicals, enhancing their versatility.
Standardization: Standardized sizes and global availability can lead to lower costs in production and procurement.
Long-Term Savings: Reduced leakage, lower maintenance needs, and improved reliability contribute to long-term cost savings.
Understanding the different types of metric hydraulic fittings is crucial for selecting the right components for a hydraulic system. Each type has its unique characteristics and applications, ensuring that the system operates efficiently and reliably. When choosing metric hydraulic fittings, it is essential to consider factors such as pressure rating, sealing method, and compatibility with other system components to ensure optimal performance.
The benefits of buying Metric fittings from QC Hydraulics?
NPT (National Pipe Tapered) style pipe threads have been widely used for over 100 years. NPT is a U.S. standard for tapered threads used on pipes and fittings. They are used to effectively seal pipes for fluid and gas transfer. The nominal pipe size can be identified by physically measuring the thread diameter, then subtracting 1/4″.
They are available in iron or brass for low-pressure applications and carbon steel and stainless steel for high-pressure.
NPTF (National Pipe Tapered Fuel) style connections are widely used in fluid power systems. They have a tapered thread by which a seal is made by deformation of the threads. NPTF Threads are measured at the thread diameter and subtracting 1/4-inch to establish the nominal pipe size.
NPSM (National Pipe Straight Mechanical) connections are also often found in fluid power systems. The female component incorporates a straight thread with an inverted 30° seat. The male component has a straight thread and a 30° internal chamfer. A seal is made by compression of the 30° seat on the chamfer. This is considered a mechanical connection. If an NPTF male is properly chamfered it will also seal with an NPSM female connection.
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Society of Automotive Engineers Thread (SAE)
SAE J Straight Thread O-Ring Boss (ORB) is recommended by the National Fire Protection Association (N.F.P.A.) for leak prevention in medium and high pressure hydraulic systems. The male connection is a straight thread with an O-ring. The female port has a straight thread and a machined surface to provide a smooth, flat surface (minimum spotface), along with a chamfer where the O-ring seats. It seals when the O-ring is compressed into the chamfer when mating the male connection. This is also considered a mechanical connection.
SAE J514 JIC/37° Hydraulic connections are common in most fluid power systems. Both male and female components have 37° seats. The seal is made by establishing contact between the male flared and female coned seat. This is also considered a mechanical connection.
SAE J512 45° connections are used in automotive, refrigeration and truck pipe systems. These connectors are typically brass material. The male and female connections have 45° seats, where the seal is make where the male flare and the female cone meet. This is a mechanical connection also.
NOTE dash sizes: -02, -03, -04, -05, -08, and -10 of SAE 37° and SAE 45° have the same threads, but NOT the same seat angles. Intermixing the two different types of fittings will result in leakage, so use care in measuring seat angles.
SAE J (ORFS) O-ring Face Seal connections are considered the best for leak control. The male connector has a straight thread and an O-ring in the face. The female has a straight thread and a machined flat face. The seal takes place by compressing the O-ring onto the flat face of the female, similar to the split flange type fitting. The threads maintain the connection mechanically.
SAE J512 Inverted connections are typically used in automotive systems. The male connector is either a 45° flare within the tube fitting or a 42° seat in the machined adapter. The female incorporates a straight thread with a 42° inverted flare. The fittings are sealed at the flared surfaces. These threads also maintain a mechanical connection.
SAE J518 4-Bolt Flange* There are two pressure ratings for these connections: Code 61 which is considered the standard series and Code 62 which is the PSI series. The design is the same for each series, yet the flange head diameters and bolt hole spacing are larger for the PSI high pressure Code 62 connection. The female port of the fitting is a smooth, un-threaded port with four bolt holes set in a rectangular pattern around the port. The male is a flanged head with a groove for an O-ring and either split or captive flange halves and bolt holes which match the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts.
*Excluding bolt sizes, SAE J518, JIS B , ISO/DIS and DIN are interchangeable.
British Standard Pipe (BSP) and BSPT (tapered) connections are comparable to NPT, except most sizes have a different thread pitch, plus the OD’s and thread form are close, but not the same. Sealing takes place by distortion of the threads. Because of this, thread sealants are recommended when securing these connections.
BSPP (parallel) male connection is comparable to NPSM male except most sizes have a different thread pitch. A captive seal is made using metal to metal angled surfaces or a combination of metal to metal and an O-ring. This type of connection is very similar (but not interchangeable) with the American NPSM male. The female swivel BSPP has a tapered nose flareless swivel where the seal occurs on the cone seat of the male connector.
Note: the thread sizes are often expressed as fractional dimensions preceeded by the letters “G” or “R”, where “G” represents a parallel thread and “R” represents a tapered thread. Example: BSPT 5/8-14 can be designated by R 5/8 and BSP 1/16-28 can be designated by G 1/16.
JIS Tapered Pipe (PT) has metric threads per JIS B . These are JIS tapered threads and are comparable to the design of BSPT connections in their dimensions and appearance. JIS tapered thread connections are interchangeable with BSPT connections.
JIS 30° Male Inverted Seat connections are parallel pipe threads per JIS B . JIS parallel connections are comparable to BSPP connections. JIS parallel thread connections are interchangeable with BSPP connections.
JIS 30° Female (Cone) Seat are parallel pipe threads per JIS B . Japanese JIS 30° flare connections are comparable to American SAE 37° flare connections in application and sealing principals. Yet, JIS 30° flare angle and dimensions are different with threads that are similar to BSPP.
JIS B 4-Bolt Flange connections are frequently used in fluid power systems. There are two pressure ratings for JIS B 4-Bolt Flange fittings:
1) Type I Code 61 is the standard series 4-Bolt Flange
2) Type II Code 62 is the PSI series
Each design concept is the same, yet the flanged head diameters and bolt hole spacing are larger for the Type II PSI connection. Metric and inch bolts are each used with these connectors. The male connector has a flanged head with a groove for seating an O-ring and either a captive flange or split flange with bolt holes to correspond to the port. The female port of the fitting is a smooth, un-threaded port with four bolt holes set in a rectangular pattern in around the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts.
JIS 210 Kgf/cm2 4-Bolt Square Flange incorporates a JIS 4-bolt square flange connection which is comparable to SAE 4-bolt flange connections with one difference – the flange itself is different and the JIS bolt pattern is square.
ISO/DIS 4-Bolt Flange is another common connection found in fluid power systems. There are two pressure ratings for this connection- Code 61: PN 35/350 bar which is considered the standard series and Code 62: PN 415 bar which is the high pressure series. They maintain the same design, yet with the bold hole spacings and flanged head diameters being larger on the PN 415 bar high pressure connection. Inch or metric bolts are found in these connections, however there is an “M” stamped on the port if metric bolts are to be used. The female port of the fitting is a smooth, un-threaded port with four bolt holes set in a rectangular pattern in around the port. The male is a flanged head with a groove for an O-ring to seat and either split or captive flange halves and bolt holes which match the port. The seal is made where the O-ring is compressed between the flanged head and the flat surface of the port. The connection is held by threaded bolts.
ISO Port and Stud Ends with ISO 261 Threads and O-ring Seal though it is similar to the SAE J514 Straight Thread O-ring Boss (ORB), this type of connection incorporates metric threads. The male connector has straight threads with an O-ring. The female port is also straight threads machined surface to provide a smooth, flat, accurately located surface (minimum spotface), along with a chamfer where the O-ring seats. It seals when the O-ring is compressed into the chamfer when mating the male connection. This is also considered a mechanical connection.
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