Compression Fittings

The 24° stainless steel cutting ring fitting, compliant with European standard ISO 8434, is a fitting designed for connecting and joining pipes. It is used in many industries where liquid or gaseous media must be transported and where the highest demands are placed on materials and sealing performance.

These include, among others, plant engineering with its diverse applications in the fields of hydraulics and pneumatics, as well as the paper, chemical, and food industries. In addition, it is used both in the general oil and gas sector and specifically with hydrogen.

The cutting ring fitting consists of three components: a socket, the cutting ring, and the union nut. Functionality is only guaranteed when combined with a seamless drawn tube. The socket, with its standardized 24° connection cone, serves as the media-carrying base body and is available in straight, elbow, T-shaped, or cross configurations.

The heart of the cutting ring fitting is the cutting ring. Schwer Fittings uses a hardened 2-edge cutting ring with a specially developed cutting contour, which has proven itself millions of times over. This ring actually cuts into the pipe with both edges and performs both the sealing and retaining functions of the connection.

When the union nut is tightened during final assembly in the socket, the pre-assembled cutting ring is guided into the socket’s cone. The seal is created by the cone in the socket and the cut in the pipe. The cutting ring must be pre-assembled with a hardened pre-assembly socket. This can be done manually or with an electro-hydraulic machine.

During pre-assembly, the cutting ring is pressed into the 24° cone of the pre-assembly fitting using the cap nut. The cone guides the cutting edges into the surface of the pipe, creating an incision with both cutting edges. An annular ring of material forms on the pipe surface at the end of the cutting edge.

If the pipe is cut exactly at a right angle and cleanly deburred, three distinct points can be sealed in the fully assembled fitting.

Pre-assembly in the socket is not possible, as this would damage the sealing surface. Only the final assembly of the fitting takes place in the socket. To ensure proper functioning of the fitting, please also refer to our installation instructions and videos with the corresponding pipe recommendations.

Cutting ring fittings are used in numerous industrial applications where a secure, metal-to-metal sealed, and pressure-resistant pipe connection is required. They are among the most important connection systems in fluid technology and ensure that piping functions reliably, vibration-resistant, and leak-free even under high operating pressures and dynamic loads. Particularly in hydraulics and pneumatics, compression fittings have been used successfully for years due to their robust construction and consistent sealing performance.

In the process industry as well—such as in the chemical industry, pharmaceutical and food production, or petrochemicals— stainless steel compression fittings are used because they must meet the highest standards for purity, corrosion resistance, and safety.

The mechanical and plant engineering sectors also make extensive use of compression fittings, for example in manufacturing machines, automation systems, or robotic systems, where robust and releasable pipe connections are required. In addition, they are used in energy and power plant technology, paint and surface treatment technology, as well as in laboratory and testing technology. Due to their high temperature and pressure resistance, their resistance to&highly aggressive media, and their reliable sealing function, compression fittings are suitable for virtually any industry in which media must be safely and controllably conveyed through piping systems.

The cutting ring fittings are divided into 3 series:

LL: for compressed air, plastic tubing, laboratories, and equipment manufacturing; primarily for low-pressure applications up to a maximum of PN 100

L: for higher pressure loads up to max. PN 315, in the fields of measurement and control technology, the paper and plastics industries, the pharmaceutical industry, aviation, hydraulic systems, and the paint and coatings industry.

S: for severe pressure surges, vibrations, and high mechanical stresses in heavy machinery construction, shipbuilding, mining, chemical industry, large-scale refrigeration systems, port and lock facilities, offshore, petrochemicals, typically in the pressure range from 250 to PN 400; up to PN 630 when using conical screw-in threads.

Schwer Fittings' cutting rings are marked with a lot number as standard. Because all components of the cutting ring fitting are marked, the manufacturing process can be traced back to the raw material, making it possible to issue a material certificate even years later. For critical process parameters, we offer a comprehensive selection of additional cutting ring variants.

The union nuts are marked in accordance with standards, indicating size, pressure rating, material, and manufacturer’s logo. Here too, traceability is ensured for Schwer Fittings via a test number. A surface coating to prevent cold welding of the nut is available upon request.

The significant advantages also include:

• extremely good cutting performance
• high tightness, no rust formation on the surface
• secure installation
• no "settling" of the cutting ring

Combination with sealing cone fittings:
The direction-adjustable 24° stainless steel sealing cone fittings are suitable for connection to threaded sockets according to DIN 3853 with 24° internal cones.

Combination with weld cone:
With the 24° weld cone fitting, the pipe welding side is adapted to standard pipe dimensions depending on the diameter and wall thickness. The seal between the fitting body and the weld nipple is provided by an O-ring mounted on the 24° cone of the weld nipple. Tightening a cap nut presses the welding cone with the O-ring into the 24° cone of the fitting body.

Please refer directly to the product page in the eShop for all technical specifications, including pressure ratings. Please also review the technical notes, data sheets, and installation instructions to ensure safe and proper installation of the compression fitting.

When installing stainless steel pipes, pre-assembly must be performed exclusively in the hardened VOMO. Direct installation in the stainless steel fitting must be avoided! The cones of the VOMOS are subject to wear and must therefore be checked at regular intervals using a cone gauge to ensure they remain within specifications. To prevent incorrect installation from the outset, worn VOMOS must be replaced with new ones.

Please be sure to follow our installation instructions under "→ Service → Installation Instructions".

At Schwer Fittings, an experienced team of in-house and field staff is always available to provide you with expert advice. In addition, the company has specialized staff in product management who are responsible for all product areas of stainless steel pipe connection technology. The team is complemented by experts (m/f/d) in business development—particularly for hydrogen applications (H2 technology) and the process industry.

Close collaboration with our customers ensures the highest technical precision, efficiency, and long-term operational reliability. You can find all contact options under “„→ Worldwide Contact“”. Further information on technical services and support is available in the “„→ Technical Service“” section.