Pressure Vessel Flange
We supply high-performance stainless steel flanges for pressure vessels, fully compliant with ASME, EN, JIS and GOST standards.
Our STRENGTHS
At Longan Flange, we understand the critical role flanges play in the integrity and safety of pressure vessels. Our mission is to provide reliable, corrosion-resistant, high-performance flanges that stand up to the most demanding industrial conditions — from chemical reactors to superheated steam drums.
We help you solve challenges like:
- Preventing Leaks Under High Pressure
- Resisting Corrosion from Harsh Chemicals
- Handling Thermal Shock and Mechanical Stress
- Customizing for Complex Nozzles and Interfaces
- Extending Service Life and Reducing Downtime
EXPLORE OUR sTAINLESS STEEL FLANGES FOR PRESSURE VESSEL
We offer a complete range of stainless steel flanges designed to meet the mechanical and chemical demands of pressure vessel systems, with full compliance to global standards.
- Welding Neck Flanges – for high-pressure, high-temperature applications
- Slip-On Flanges – easy installation for lower-pressure systems
- Blind Flanges – sealing off vessel ends or nozzles
- Socket Weld & Lap Joint Flanges – for compact or specialized configurations
- Custom Flanges – made to your drawings or specifications
EXPLORE OUR sTAINLESS STEEL FLANGES FOR PRESSURE VESSEL
All flanges are available with customized sealing faces (RF, RTJ, FM), bolt hole patterns, and surface finishes.
International standards supported:
- ASME/ANSI
- DIN
- EN
- JIS
- GOST
We also offer customized pressure vessel flanges to meet your unique and demanding operating conditions.
CONTACT OUR SPECIALIST now and let us know your requirements—we will get back to you within 24 hours.
PRODUCT CATALOG
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Custom Machining for Vessel Integration
- Custom bolt hole patterns to match vessel heads, nozzles, or manways.
- Machined to match dish ends, jacketed vessels, and internal reinforcements.
- Available in long weld neck and integral flange-nozzle combinations.
- Flanges can be supplied with grooves, radii, or bevels as per fabrication needs.
Pressure-Temperature Compatibility
- Designed to meet ASME Section VIII Div. 1 and EN 13445 pressure vessel codes
- Suitable for Class 150–2500 / PN6–PN400 pressure ratings
- Operable in cryogenic (-196°C) to superheated (+600°C) applications
- Withstands thermal cycling without deformation or leakage
Structural Strength & Stress Resistance
- Designed to handle external loads from piping, vibration, and thermal expansion.
- Suitable for flanged joints exposed to vacuum, pulsating pressure, and cyclic loads.
- Made with forged or heat-treated material to improve strength and toughness
- Optional finite element analysis (FEA) support for critical flange designs.
Fast Delivery and Support for Projects
- Standard sizes ready in stock for quick delivery
- Custom flanges delivered in 2–4 weeks depending on complexity
- Support for third-party inspection (TPI) and export packaging
- Engineering support for flange selection, drawing review, and material choice
Where Our Flanges Are Used
Urea Production Plants
High-pressure flange connections in urea synthesis loops
Acid/Alkali Transport Pipelines
Pipeline systems for sulfuric acid, nitric acid, hydrochloric acid, sodium hydroxide, etc.
Storage Tanks and Pressure Vessels
Manway flanges, nozzles, and inspection ports on chemical storage tanks
Heat Exchangers and Reactors
Connection of heat exchanger tubes, condensers, evaporators, and chemical reactors
Certifications
Exhibition
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Yes. Our flanges meet the requirements of ASME Section VIII Div.1, PED (EU Pressure Equipment Directive), and other relevant pressure vessel codes. Certification options include:
- ASME B16.5 / B16.47
- EN 1092-1, DIN, GB/T
- NACE MR0175 / ISO 15156 for sour service
- Full material traceability and optional 3.2 certification available
The most commonly used flange types in pressure vessels include:
- Weld Neck Flange (WN): Ideal for high pressure and temperature, with a long hub for stress distribution
- Blind Flange (BL): Used to close vessel ends or nozzles
- Long Weld Neck Flange (LWN): Common for nozzle connections
- Integral or Custom Flange-Nozzle Units: For seamless integration into vessel heads
We manufacture flanges to match precisely your nozzle and shell layout, based on:
- Custom bolt hole patterns and facing types
- Weld end preparation according to your WPS
- Matching ID/OD with vessel necks or manways
- Machined-to-fit dish heads, jackets, and reinforcement pads
We supply flanges suitable for both low- and high-pressure vessels:
- ASME Classes: 150, 300, 600, 900, 1500, and 2500
- EN Pressure Ratings: PN6 to PN400
- Pressure-temperature ratings are verified according to P-T charts in ASME B16.5 / EN 1092
Yes. Our pressure vessel flanges are designed to withstand:
- Operating temperatures from -196°C to +600°C
- Thermal expansion and contraction in start-stop processes
- Cyclic pressure loads common in reactors, boilers, and heat exchangers
- Optional heat treatment like normalization or PWHT to enhance performance
Absolutely. We ensure sealing reliability by:
- Machining sealing faces to Ra 3.2 μm or better
- Supporting RTJ, RF, FF, and custom sealing configurations
- Compatibility with metallic gaskets, spiral wound, and kammprofile gaskets
- Optional hydrostatic or helium leak testing available
Yes, we support full pressure vessel compliance requirements, including:
- EN 10204 3.1 / 3.2 certificates
- NDT reports: UT, RT, MPI, PT
- Dimensional inspection reports
- Third-party inspection (TÜV, Lloyd’s, SGS, BV, etc.) coordinated in-house
Definitely. Our engineering support includes:
- Reviewing vessel drawings and nozzle layouts
- Recommending flange types, sealing faces, and materials
- Providing stress analysis support for critical flanged joints
- Helping ensure full compliance with ASME / PED / ISO pressure vessel codes
