Copper Nickel Composite Slip On Flanges
Copper Nickel Composite Slip On Flanges are engineered for seawater piping systems where corrosion resistance and cost efficiency are equally important. Instead of manufacturing the entire flange from expensive copper nickel alloy, this composite design combines a copper nickel sealing component with a carbon steel backing flange, providing the corrosion performance of copper nickel while significantly reducing material costs.
Compared with solid copper nickel flanges, composite slip on flanges offer easier installation, lower project investment, and excellent long-term reliability in aggressive seawater environments.
HC can supply CuNi 90/10 and CuNi 70/30 composite slip on flanges according to ANSI, ASME, EN, DIN, JIS, GB, EEMUA standards or customized project drawings. Sizes, pressure ratings, facing types, bolt holes, backing flange coating and inspection documents can be provided according to customer requirements.
- Product: Copper Nickel Composite Slip On Flanges
- Structure: CuNi inner collar with carbon steel backing flange
- Copper Nickel Material: CuNi 90/10 (C70600) and CuNi 70/30 (C71500)
- Backing Flange: Carbon steel loose flange
- Available Sizes: DN15–DN1200 (1/2"–48")
- Pressure Ratings: PN6–PN25, ASME Class 150/300, JIS 5K/10K
- Manufacturing Standards: ASME, EN, DIN, JIS, GB, EEMUA or project drawings
- Connection Type: Slip-on with double fillet weld
- Typical Applications: Marine, offshore, seawater piping and desalination systems
- Manufacturer: HC
- Custom manufacturing available according to project drawings
What Is a Copper Nickel Composite Slip On Flange?
A Copper Nickel Composite Slip On Flange is a combined flange assembly used to connect copper nickel pipes. The inner collar is normally made from copper nickel alloy such as 90/10 CuNi or 70/30 CuNi. This part is in contact with the pipe and medium, so it provides excellent resistance to seawater corrosion, biofouling, and erosion.
The outer backing flange is usually made from carbon steel. It does not contact the fluid directly, but provides bolt support and mechanical strength. This structure allows the flange to perform well in harsh marine environments while reducing the overall material cost.
Copper Nickel Composite Slip On Flanges generally include:
Copper Nickel Inner Flange / Collar / Stub End
The CuNi part is welded to the copper nickel pipe and contacts the seawater or process medium.
Carbon Steel Outer Flange / Loose Flange / Backing Flange
The carbon steel flange provides bolt holes and clamping force for flange connection.
This design is similar to composite weld neck flanges, but the connection method with the pipe is different. Composite weld neck flanges are connected by butt welding, while composite slip on flanges slip over the pipe and are fixed by fillet welding.
For matching pipe products, please check our Copper Nickel Pipes and Copper Nickel Pipe Fittings.
Copper Nickel Composite Slip On Flange Specifications
| Item | Specification |
| Product Name | Copper Nickel Composite Slip On Flanges |
| Manufacturer | HC |
| Product Structure | Copper Nickel Inner Flange (Collar / Stub End) + Carbon Steel Backing Flange (Loose Flange) |
| Inner Part | Copper Nickel Collar, Copper Nickel Inner Flange, Copper Nickel Stub End |
| Outer Part | Carbon Steel Loose Flange, Carbon Steel Backing Flange |
| Inner Material Grade | CuNi 90/10 (C70600), CuNi 70/30 (C71500) |
| CuNi Standards | EEMUA 144, NES 780, DEF STAN, ASTM B151, ASTM B466, ASTM B467 or project specification |
| Backing Flange Material | Carbon Steel, optional Stainless Steel or other materials |
| Surface Treatment | Black Painting, Anti-rust Oil, Hot-dip Galvanized, Epoxy Coating, Zinc Coating or Customized |
| Flange Type | Composite Slip On Flange, Composite Loose Flange, Composite Ring Flange |
| Connection Method | Slip-on Installation with Fillet Welding |
| Welding Type | Double Fillet Weld (Top & Bottom) |
| Compared with Weld Neck Type | Slip On uses fillet welding; Weld Neck uses butt welding |
| Nominal Size | DN15–DN1200 (1/2"–48"), larger sizes available |
| Pressure Rating | PN6, PN10, PN16, PN25, ASME Class 150/300, JIS 5K/10K or Customized |
| Available Standards | ANSI/ASME, EN, DIN, JIS, GB, EEMUA, BS or Customer Drawings |
| Facing Type | RF, FF, Raised Face, Flat Face or Customized |
| Bolt Holes | According to Selected Standard or Project Drawing |
| Neck Design | Low Neck Design for Improved Rigidity |
| Inside Diameter | Slightly Larger than Pipe Outside Diameter for Easy Slip-on Assembly |
| Matching Pipe | Copper Nickel Pipe, CuNi 90/10 Pipe, CuNi 70/30 Pipe |
| Service Media | Seawater, Cooling Water, Ballast Water, Fire Water, Desalination Water |
| Applications | Shipbuilding, Offshore Platforms, Marine Engineering, Desalination Plants, Seawater Cooling Systems, Coastal Power Plants |
| Main Advantages | Lower Cost, Excellent Seawater Corrosion Resistance, Easy Installation, Flexible Alignment, Reduced Copper Nickel Consumption |
| Inspection | Dimensional Inspection, Visual Inspection, Material Verification, Surface Inspection |
| Certificates | EN 10204 3.1, Material Certificate, Chemical Analysis, Mechanical Properties Report, PMI (Optional) |
| Customization | Available for Size, Pressure Rating, Material Grade, Coating, Facing Type, Bolt Holes and Drawings |
| Packaging | Plywood Cases, Wooden Pallets, Plastic Film Protection, Seaworthy Export Packing |
| Supply Scope | Composite Slip On Flanges, Copper Nickel Pipes, Elbows, Tees, Reducers, Weld Neck Flanges and Related Pipe Fittings |
Features of Copper Nickel Composite Slip On Flanges
Cost-Effective Composite Construction
Only the sealing collar is manufactured from copper nickel alloy, while the backing flange is produced from carbon steel. This composite design significantly reduces material costs without compromising corrosion resistance in seawater service.
Easy Installation
The slip-on design allows the flange to slide directly over the pipe before welding. Double fillet welding provides a secure connection while reducing fabrication time compared with butt-weld flange designs.
Excellent Seawater Corrosion Resistance
The sealing surface is manufactured entirely from copper nickel alloy, providing excellent resistance to seawater, chloride attack, salt spray, marine organisms and biofouling in harsh marine environments.
Flexible Bolt Hole Alignment
The carbon steel backing flange rotates independently from the copper nickel collar, allowing easy bolt hole alignment and simplifying field installation.
Lower Inventory Cost
Standard backing flanges can be combined with different copper nickel collars, reducing stock requirements while increasing project flexibility.
Reliable Mechanical Strength
The carbon steel backing flange provides excellent rigidity and load-bearing capability while remaining isolated from the process media, ensuring long service life and dependable mechanical performance.
Marine Flanges Available Copper Nickel Materials
HC manufactures Copper Nickel Composite Slip On Flanges using multiple copper nickel alloys to meet different marine engineering and offshore project requirements.
CuNi 90/10 (UNS C70600)
CuNi 90/10 is the most widely used copper nickel alloy for marine piping systems, combining excellent seawater corrosion resistance with good weldability and economical cost.
Advantages
- Excellent seawater corrosion resistance
- Outstanding resistance to biofouling
- Easy fabrication and welding
- Competitive material cost
- Long service life
Typical Applications
- Ship cooling systems
- Ballast water pipelines
- Fire-fighting systems
- Condenser piping
- Heat exchangers
CuNi 70/30 (UNS C71500)
CuNi 70/30 provides higher mechanical strength and superior erosion-corrosion resistance, making it ideal for severe marine environments and high-flow seawater systems.
Advantages
- Better erosion-corrosion resistance
- Suitable for high flow velocity
- Higher pressure capability
- Excellent chloride resistance
- Long operating life
Typical Applications
- Offshore platforms
- Naval vessels
- Seawater desalination plants
- Power stations
- Marine condensers
Copper Nickel Flanges Chemical Composition
90/10 (UNS C70600) Copper Nickel Flanges Chemical Composition
| KME CuNi90/10 | DIN 17664 2.0882 | BS 2871 CN102 | ASTM B466 C70600 | JIS H3300 C7060T | DIN 86019 2.1972 | EEMUA 234 UNS 7060X | GB/T 5231 BFe10-1.6-1 | |
| Ni% | 10.0-11.0 | 9.0-11.0 | 10.0-11.0 | 9.0-11.0 | 9.0-11.0 | 9.0-11.0 | 10.0-11.0 | 9.0-11.0 |
| Fe% | 1.5-1.8 | 1.0-2.0 | 1.0-2.0 | 1.0-1.8 | 1.0-1.8 | 1.5-1.8 | 1.5-2.0 | 1.5-1.8 |
| Mn% | 0.6-1.0 | 0.5-1.0 | 0.5-1.0 | max.1.0 | 0.2-1.0 | 0.5-1.0 | 0.5-1.0 | 0.5-1.0 |
| C% | max.0.05 | max.0.05 | max.0.05 | max.0.05 | max.0.05 | max.0.05 | max.0.05 | |
| Pb% | max.0.01 | max.0.03 | max.0.01 | max.0.02 | max.0.05 | max.0.01 | max.0.01 | max.0.03 |
| S% | max.0.005 | max.0.02 | max.0.05 | max.0.02 | max.0.005 | max.0.02 | max.0.01 | |
| P% | max.0.02 | max.0.02 | max.0.02 | max.0.02 | max.0.02 | max.0.02 | ||
| Zn% | max.0.05 | max.0.50 | max.0.50 | max.0.50 | max.0.05 | max.0.20 | max.0.20 | |
| Other | max.0.20 | max.0.30 | max.0.20 | max.0.30 | max.0.40 | |||
| Cu% | rem. | rem. | rem. | rem. | +Ni+Fe+Mn min99.5 | rem. | rem. | rem. |
70/30 (UNS C71500) Copper Nickel Flanges Chemical Composition
| KME CuNi70/30 | DIN 176642.0882 | BS 2871 CN107 | ASTM B466C71500 | JIS H3300C7150T | |
| Ni% | 30.0-32.0 | 30.0-32.0 | 30.0-32.0 | 29.0-33.0 | 29.0-33.0 |
| Fe% | 0.47-0.7 | 0.4-1.0 | 0.4-1.0 | 0.4-1.0 | 0.4-1.0 |
| Mn% | 0.5-1.0 | 0.5-1.5 | 0.5-1.5 | max.1.0 | 0.2-1.0 |
| C% | max.0.04 | max.0.05 | max.0.06 | max.0.05 | |
| Pb% | max.0.01 | max.0.03 | max.0.01 | max.0.02 | max.0.05 |
| S% | max.0.01 | max.0.02 | max.0.08 | max.0.02 | |
| P% | max.0.02 | max.0.02 | max.0.02 | ||
| Zn% | max.0.20 | max.0.50 | max.0.50 | max.0.50 | |
| Other | max.0.30 | max.0.30 | |||
| Cu% | rem. | rem. | rem. | rem. | +Ni+Fe+Mn min99.5 |
Available Standards & Custom Manufacturing
Our Copper Nickel Composite Slip On Flanges are manufactured to international standards and can also be customized to meet project-specific engineering requirements.
Supported Standards
- ASTM
- ASME
- EEMUA
- DIN
- EN
- ANSI
- ISO
- JIS
- BS
- Customer Drawings
Customization Options
- Custom flange dimensions
- Pressure class customization
- Bolt hole drilling patterns
- Special facing types (RF / FF)
- Project-specific markings
- Inspection documents upon request
Our engineering team can manufacture composite slip on flanges according to your drawings or technical specifications, ensuring compatibility with new installations, replacement projects, and marine piping systems.
Typical Applications of Copper Nickel Composite Slip On Flanges
Copper Nickel Composite Slip On Flanges are widely specified for seawater piping systems where corrosion resistance, reliable sealing performance, and cost efficiency are equally important. By combining a copper nickel sealing face with a carbon steel backing flange, they provide long-term durability while reducing overall material costs compared with solid copper nickel flanges.
- Marine and commercial shipbuilding piping systems
- Offshore oil, gas, and renewable energy platforms
- Seawater cooling and circulation pipelines
- Firefighting and fire water distribution systems
- Ballast water treatment and transfer systems
- Desalination plants and seawater intake facilities
- Heat exchangers, condensers, and cooling equipment
- Coastal power stations and industrial utilities
- Naval vessels and marine engineering projects
Manufactured in CuNi 90/10 and CuNi 70/30 grades, Copper Nickel Composite Slip On Flanges offer excellent resistance to seawater corrosion, biofouling, and erosion. Their proven service life and ease of installation make them a dependable choice for both new construction and maintenance projects in demanding marine environments.
Composite Slip On Flanges vs Composite Weld Neck Flanges
The main difference between composite slip on flanges and composite weld neck flanges is the pipe connection method.
| Item | Composite Slip On Flange | Composite Weld Neck Flange |
| Connection type | Slip over pipe + fillet weld | Butt weld connection |
| Installation | Easier alignment | Stronger welded joint |
| Cost | Usually economical | Usually higher |
| Welding work | More fillet welding | Butt welding |
| Welding Time | Shorter | Longer |
| Welding Material | Less | More |
| High Pressure | Good | Excellent |
| Common use | General seawater piping | Higher pressure or critical lines |
Both types can be used in marine and offshore piping systems. The right choice depends on working pressure, pipe size, installation space, project specification, and class requirements.
For higher-pressure applications, our Copper Nickel Composite Weld Neck Flanges are often recommended.
You can compare more options from our Marine Copper Nickel Flanges product range.
Quality Assurance & Inspection
Every Copper Nickel Composite Slip On Flange is manufactured under a documented quality management process. From raw material verification to final packaging, each flange is inspected to ensure dimensional accuracy, material compliance, and reliable performance in seawater, offshore, and marine piping systems.
Inspection Capabilities
- Positive Material Identification (PMI)
- Chemical composition verification
- Dimensional and tolerance inspection
- Surface finish and visual examination
- Wall thickness measurement
- Mechanical property testing
- Hydrostatic pressure testing (when specified)
- Third-party inspection available (SGS, BV, DNV, LR, ABS, TUV)
Inspection Documents Supplied
Complete inspection records and shipping documents are available according to customer specifications and project requirements.
- EN 10204 3.1 Material Test Certificate (MTC)
- Dimensional Inspection Report
- Chemical Analysis Report (upon request)
- Packing List
- Commercial Invoice
- Certificate of Origin (COO)
Additional inspection procedures and documentation can be arranged to meet marine classification society requirements, offshore project specifications, and international procurement standards.
Copper Nickel Flange Export Packaging
Every Copper Nickel Flange is carefully packed to prevent damage during storage, inland transportation, and international shipping. Packaging methods are selected according to the flange size, quantity, destination, and customer requirements to ensure the products arrive in excellent condition.
- Strong wooden export cases for maximum protection
- Fumigation-free plywood boxes suitable for global shipments
- Steel pallets for large-size or heavy flanges
- Cartons with protective cushioning for small orders
- Custom export packaging available for project deliveries
Each package is securely fastened and clearly marked with product grade, size, specification, heat number, purchase order, and shipping information, allowing fast identification and efficient inventory management upon arrival.
Why Choose Our Copper Nickel Composite Slip On Flanges?
We focus on copper nickel piping products for marine and seawater applications. Our composite slip on flanges are produced with strict dimensional control, proper material selection, and reliable welding preparation.
We can provide:
- Complete marine piping product range
- Available in CuNi 90/10 (C70600) and CuNi 70/30 (C71500)
- Strict raw material inspection and quality control
- Precision machining for accurate dimensions
- Stable dimensional accuracy and reliable fit-up
- Competitive factory-direct pricing
- OEM and customized manufacturing available
- Fast global delivery with export-grade packaging
- Experienced international sales and export team
- Technical support before and after sales
To complete your piping system, you can also browse our Copper Nickel Elbows, Copper Nickel Tees, and Copper Nickel Reducers.
Whether you are building a new marine piping system or replacing existing seawater components, our composite slip on flanges provide an economical and reliable solution.
Frequently Asked Questions
What is a Copper Nickel Composite Slip On Flange?
A Copper Nickel Composite Slip On Flange is a two-piece flange assembly consisting of a copper nickel collar (stub end) and a carbon steel backing flange. The copper nickel collar is the wetted component that provides excellent seawater corrosion resistance, while the backing flange delivers mechanical strength and simplifies installation.
What are the advantages of a composite slip on flange?
The primary advantage is lower material cost without sacrificing corrosion performance. Only the sealing surface is manufactured from copper nickel alloy, while the carbon steel backing flange provides structural support, significantly reducing the amount of expensive copper nickel material required.
Is the carbon steel backing flange exposed to seawater?
Under normal operating conditions, no. The carbon steel backing flange is not in direct contact with the process medium. The copper nickel collar forms the corrosion-resistant sealing surface that contacts seawater.
What is the difference between composite slip on and composite weld neck flanges?
The main difference is the connection method. Composite slip on flanges are installed over the pipe and secured with fillet welds, making installation faster and more economical. Composite weld neck flanges are butt welded to the pipe, providing higher strength for demanding pressure applications.
Which copper nickel materials are available?
We manufacture composite slip on flanges in CuNi 90/10 (UNS C70600), CuNi 70/30 (UNS C71500), and other project-specified copper nickel alloys to meet different marine and industrial requirements.
Can you manufacture custom sizes and standards?
Yes. Custom outside diameters, pressure classes, drilling patterns, dimensions, and international standards can be produced according to customer drawings and project specifications.
Do you provide complete copper nickel piping solutions?
Yes. In addition to Copper Nickel Composite Slip On Flanges, we manufacture Copper Nickel Pipes, Composite Weld Neck Flanges, Elbows, Equal Tees, Reducers, Caps, and other marine piping fittings, allowing customers to source a complete copper nickel piping system from one supplier.
Send Your Inquiry
If you need Copper Nickel Composite Slip On Flanges for shipbuilding, offshore, or seawater pipeline projects, please send us your size, material grade, standard, pressure rating, and quantity. Our team will provide a suitable quotation and technical support for your project.
Contact us today for Copper Nickel Composite Slip On Flanges and complete CuNi piping solutions.
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