Technical specifications and application of DIN 2634 flanges
The DIN 2634 standard regulates the geometric parameters and design requirements for welding neck flanges designed for a working pressure of PN 25 kgf/cm² in the nominal diameter range from DN 10 to DN 1000. In the EV Group China product range, these items are presented as highly reliable components of piping systems for the airtight connection of valves, pressure vessels, and connection assemblies.
Structurally, the flange is a disc with holes for fasteners (bolts or studs) and a tapered protrusion (“neck”) that ensures a smooth transition to the pipe being welded. This geometry minimizes stress concentration in the weld zone, which is critical for high-responsibility pipelines.
The technical documentation of the standard defines:
- Overall and connecting dimensions;
- Basic material requirements;
- Surface finish parameters for sealing faces;
- Calculated mass values of the products.
Production processes, acceptance test regulations, and marking comply with the DIN 2519 standard, and the types of sealing surfaces are determined according to DIN 2526.
Materials and operational capabilities
To manufacture DIN 2634 flanges, EV Group China uses a wide range of steels:
- Carbon steels for general industrial use;
- Alloy steels for operation under high loads;
- Stainless steels with high corrosion resistance;
- Heat-resistant steel grades for operation in high-temperature conditions.
When using C22 grade steel in the standard version, the permissible operating temperature is up to 120°C with full compliance with the nominal pressure PN 25. When the temperature increases in the range from 120°C to 300°C, it is necessary to take into account the reduction in the material’s yield strength when designing the piping system.
Important note: The DIN 2634 standard is officially recognized as obsolete. In modern engineering practice, it is recommended to use the DIN EN 1092-1 (type 11B) standard for new projects, which fully complies with current safety and interchangeability requirements. EV Group China specialists are ready to provide technical consultation on transitioning to modern specifications.