Copper Nickel Weld Neck Flanges
HC Aluminum supplies copper nickel weld neck flanges for marine, offshore and seawater piping projects. Available material options include 90/10 CuNi C70600 and 70/30 CuNi C71500, with flange requirements specified to EEMUA 234 or ASME B16.5 Class 150 and Class 300, as applicable to the order.
- Material
- 90/10 C70600 · 70/30 C71500
- Connection
- Butt-weld / WN flange
- Standard
- EEMUA 234 / ASME B16.5
- ASME classes
- Class 150 · Class 300
Copper Nickel Weld Neck Flange Specifications
| Item | Specification / Order Requirement |
| Product type | Weld neck flange / WN flange |
| Material options | 90/10 copper nickel; 70/30 copper nickel |
| UNS grades | C70600; C71500 |
| Standard requirements | EEMUA 234 or ASME B16.5, as specified |
| ASME pressure classes | Class 150; Class 300 |
| Pipe connection | Butt-weld end |
| Flange size | Specify nominal size and applicable dimensional standard |
| Bore and weld end | Confirm against pipe outside diameter and wall thickness |
| Facing | Specify the required facing and gasket arrangement |
| Documentation | Identify required material certificates, inspection records and marking at enquiry |
For alternative connection designs, explore our copper nickel flanges range.
What is a copper nickel weld neck flange?
Copper nickel weld neck flanges use a long tapered hub that transitions into the pipe through a butt-welded connection. The design provides a robust load path between the flange and pipe and is commonly selected where mechanical integrity, alignment and resistance to repeated loading are important.
HC Aluminum supplies these flanges in copper nickel alloys selected for the service environment, We can manufacture or source the flange to the required dimensions, pressure class, facing, bore and project specification rather than treating every application as a standard stock item.
Copper Nickel Materials for Weld Neck Flanges
C70600 — 90/10 Copper Nickel
UNS C70600 is a 90/10 copper nickel alloy commonly used in seawater and marine piping systems. Its combination of corrosion resistance, strength and weldability makes it a widely used material for seawater cooling and offshore piping applications.
- UNS C70600
- Nominal Cu-Ni: 90/10
- CuNi10Fe1Mn
- Marine / Offshore
For 90/10 copper nickel requirements, material, dimensional and documentation requirements should be confirmed against the applicable project specification.
C71500 — 70/30 Copper Nickel
UNS C71500 is a 70/30 copper nickel alloy with higher nickel content than C70600. It is selected for applications where higher strength and enhanced resistance are required under demanding marine service conditions.
- UNS C71500
- Nominal Cu-Ni: 70/30
- CuNi30Mn1Fe
- Severe Marine Service
See our UNS C71500 70/30 copper nickel flanges page for more information about the 70/30 alloy flange product range.
Why Choose a Copper Nickel Weld Neck Flange?
Long Tapered Hub
The tapered hub provides a gradual transition from the flange body to the pipe, making the connection suitable for piping systems exposed to mechanical loads and operating fluctuations.
Butt-Welded Connection
The flange is welded directly to the pipe, creating a continuous connection that can be engineered to suit the pipe wall and project welding procedure.
Better Load Distribution
Compared with shorter flange designs, the long hub helps distribute stresses through the flange-to-pipe transition and is commonly selected for higher-integrity piping connections.
Project Specification Flexibility
Flange dimensions, bore, facing, pressure class and material can be coordinated with the connected pipe and the governing piping specification.
Copper Nickel Weld Neck Flanges Applications
Marine Seawater Systems
Used for seawater cooling, ballast-related piping and other marine systems where corrosion resistance and reliable pipe connections are important.
Offshore Platforms
Selected for offshore seawater cooling and fire-fighting piping where copper nickel alloy piping is specified for long-term marine service.
Desalination Plants
Suitable for seawater intake, cooling and associated piping in desalination facilities, subject to the design conditions and material specification of the system.
Shipbuilding
Used around marine piping networks and equipment connections where copper nickel alloys are selected for seawater service.
Condensers & Coolers
Commonly specified around condensers, coolers, pumps and other equipment connections where the piping system requires corrosion-resistant flange joints.
Marine Process Piping
Suitable for selected high-integrity marine and process piping applications where alloy selection, pressure rating and documentation are controlled by the project specification.
HC Aluminum Manufacturing & Quality Control
Our copper nickel product experience includes copper nickel pipes, marine flanges and related pipe fittings, allowing flange requirements to be coordinated with the connected piping.
We review the material grade, flange standard, pressure class, dimensions, bore and documentation requirements before production.
- Material identification and verification
- Flange dimensions and bore inspection
- Facing and surface inspection
- Welding-end dimensional checks
- Mechanical or project-specific testing
- Mill test certificates and inspection documentation
Request a Quote for Copper Nickel Weld Neck Flanges
To prepare an accurate quotation, HC Aluminum normally needs the flange material, nominal pipe size, pressure class, facing, bore, quantity and applicable standard.
Providing the connected pipe information is especially useful for weld neck flanges because the flange bore and welding end need to correspond with the piping requirements.
Recommended RFQ Information
- Material grade: C70600 or C71500
- Pipe size / NPS
- Pressure class
- Flange facing
- Pipe wall thickness or bore requirement
- Applicable standard
- Quantity
- Inspection and documentation requirements
Source Copper Nickel Weld Neck Flanges from HC Aluminum
Share your C70600 or C71500 requirements, drawings and pipe specifications for a tailored quotation.
Request a QuoteCopper Nickel Weld Neck Flanges Stock
Copper Nickel Weld Neck Flanges Stock ASME B16.5 CL 150 Stock
| specification | d1 | A | H | C | X | R | G | N-Od2 | Weight |
| inch | mm | mm | mm | mm | mm | mm | mm | kg | |
| 1/2" | 21.3 | 88.9 | 47.6 | 11.2 | 30.2 | 34.9 | 60.3 | 4-15.9 | 0.68 |
| 3/4" | 26.7 | 98.4 | 52.4 | 12.7 | 38.1 | 42.9 | 69.8 | 4-15.9 | 0.91 |
| 1" | 33.4 | 107.9 | 55.6 | 14.3 | 49.2 | 50.8 | 79.4 | 4-15.9 | 1.25 |
| 11/4" | 42.2 | 117.5 | 57.1 | 15.9 | 58.7 | 63.5 | 88.9 | 4-15.9 | 1.58 |
| 11/2" | 48.3 | 127 | 61.9 | 17.5 | 65.1 | 73 | 98.4 | 4-15.9 | 2.05 |
| 2" | 60.3 | 152.4 | 63.5 | 19.1 | 77.8 | 92.1 | 120.6 | 4-19 | 3.05 |
| 21/2" | 73 | 177.8 | 69.8 | 22.2 | 90.5 | 104.8 | 139.7 | 4-19 | 5.10 |
| 3" | 88.9 | 190.5 | 69.8 | 23.8 | 107.9 | 127 | 152.4 | 4-19 | 5.20 |
| 4" | 114.3 | 228.6 | 76.2 | 23.8 | 134.9 | 157.2 | 190.5 | 8-19 | 7.90 |
| 5" | 141.3 | 254 | 88.9 | 23.8 | 163.5 | 185.7 | 215.9 | 8-22.2 | 10.10 |
| 6" | 168.3 | 279.4 | 88.9 | 25.4 | 192.1 | 215.9 | 241.3 | 8-22.2 | 12.20 |
| 8" | 219.1 | 342.9 | 101.6 | 28.6 | 246.1 | 269.9 | 298.4 | 8-22.2 | 20.00 |
| 10" | 273 | 406.4 | 101.6 | 30.2 | 304.8 | 323.8 | 361.9 | 12-25.4 | 27.00 |
| 12" | 323.8 | 482.6 | 114.3 | 31.8 | 365.1 | 381 | 431.8 | 12-25.4 | 42.00 |
| 14" | 355.6 | 533.4 | 127 | 34.9 | 400 | 412.8 | 476.2 | 12-28.6 | 53.00 |
| 16" | 406.4 | 596.9 | 127 | 36.5 | 457.2 | 469.9 | 539.7 | 16-28.6 | 66.00 |
| 18" | 457 | 635 | 139.7 | 39.7 | 504.8 | 533.4 | 577.8 | 16-31.7 | 72.00 |
| 20" | 508 | 698.5 | 144.5 | 42.9 | 558.8 | 584.2 | 635 | 20-31.7 | 87.00 |
| 24" | 610 | 812.8 | 152.4 | 47.6 | 633.6 | 692.1 | 749.3 | 20-34.9 | 134.00 |
Copper Nickel Weld Neck Flanges Stock ASME B16.5 CL 300
| specification | d1 | A | H | C | X | R | G | N-Od2 | Weight |
| inch | mm | mm | mm | mm | mm | mm | mm | kg | |
| 1/2" | 21.3 | 95.2 | 52.4 | 14.3 | 38.1 | 34.9 | 66.7 | 4-15.9 | 1.72 |
| 3/4" | 26.7 | 117.5 | 57.1 | 15.9 | 47.6 | 42.9 | 82.5 | 4-19 | 2.06 |
| 1" | 33.4 | 123.8 | 61.9 | 17.5 | 54 | 50.8 | 88.9 | 4-19 | 2.29 |
| 11/4" | 42.2 | 133.3 | 65.1 | 19 | 63.5 | 63.5 | 98.4 | 4-19 | 2.86 |
| 11/2" | 48.3 | 155.6 | 68.3 | 20.6 | 69.8 | 73 | 114.3 | 4-22.2 | 4.01 |
| 2" | 60.3 | 165.1 | 69.8 | 22.2 | 84.1 | 92.1 | 127 | 8-19 | 4.58 |
| 21/2" | 73 | 190.5 | 76.2 | 25.4 | 100 | 104.8 | 149.2 | 8-22.2 | 5.73 |
| 3" | 88.9 | 209.5 | 79.4 | 28.6 | 117.5 | 127 | 168.3 | 8-22.2 | 8.02 |
| 4" | 114.3 | 254 | 85.7 | 31.8 | 146.1 | 157.2 | 200 | 8-22.2 | 12.60 |
| 5" | 141.3 | 279.4 | 98.4 | 34.9 | 177.8 | 185.7 | 234.9 | 8-22.2 | 17.90 |
| 6" | 168.3 | 317.5 | 98.4 | 36.5 | 206.4 | 215.9 | 269.9 | 12-22.2 | 21.76 |
| 8" | 219.1 | 381 | 111.1 | 41.3 | 260.4 | 269.9 | 330.2 | 12-25.4 | 34.35 |
| 10" | 273 | 444.5 | 117.5 | 47.6 | 320.7 | 323.8 | 387.3 | 16-28.6 | 46.95 |
| 12" | 323.8 | 520.7 | 130.2 | 50.8 | 374.6 | 381 | 450.8 | 16-31.7 | 70.99 |
| 14" | 355.6 | 584.2 | 142.9 | 54 | 425.4 | 412.8 | 514.3 | 20-31.7 | 96.18 |
| 16" | 406.4 | 647.7 | 146.1 | 57.2 | 482.6 | 469.9 | 571.5 | 20-34.9 | 127.10 |
| 18" | 457 | 711.2 | 158.7 | 60.3 | 533.3 | 533.4 | 628.6 | 24-34.9 | 158.01 |
| 20" | 508 | 774.7 | 161.9 | 63.5 | 587.4 | 584.2 | 685.8 | 24-34.9 | 195.80 |
| 24" | 610 | 914.4 | 168.3 | 69.8 | 701.7 | 692.1 | 812.8 | 24-41.3 | 283.00 |
Copper Nickel Weld Neck Flanges EEMUA 234 Stock
| specification | d1 | D | b | K | h1 | d3 | S16bar | S20bar | h2 | N-Od2 | Weight 16bar | Weight 20bar |
| inch | mm | mm | mm | mm | mm | mm | mm | mm | mm | kg | kg | |
| 1/2" | 16 | 89 | 14 | 60.3 | 48 | 23 | 2 | 2 | 8 | 4-15.9 | 0.74 | 0.74 |
| 3/4" | 25 | 98 | 16 | 69.8 | 52 | 32 | 2 | 2 | 7 | 4-15.9 | 1.04 | 1.04 |
| 1" | 30 | 108 | 16 | 79.4 | 56 | 42 | 2.5 | 2.5 | 8 | 4-15.9 | 1.36 | 1.36 |
| 11/4" | 38 | 117 | 17 | 88.9 | 57 | 51 | 2.5 | 2.5 | 8 | 4-15.9 | 1.70 | 1.70 |
| 11/2" | 44.5 | 127 | 20 | 98.4 | 62 | 61 | 2.5 | 2.5 | 7 | 4-15.9 | 2.38 | 2.38 |
| 2" | 57 | 152 | 25 | 120.6 | 64 | 73 | 2.5 | 2.5 | 9 | 4-19 | 3.93 | 3.93 |
| 21/2" | 76.1 | 178 | 27 | 139.7 | 70 | 91 | 2.5 | 2.5 | 8 | 4-19 | 5.62 | 5.62 |
| 3" | 88.9 | 190 | 27 | 152.4 | 70 | 105 | 2.5 | 2.5 | 8 | 4-19 | 6.27 | 6.27 |
| 4" | 108 | 229 | 27 | 190.5 | 76 | 135 | 3 | 3 | 8 | 8-19 | 9.53 | 9.53 |
| 6" | 159 | 279 | 27 | 241.3 | 89 | 192 | 3 | 3.5 | 8 | 8-22.2 | 13.65 | 13.99 |
| 8" | 219.1 | 343 | 31 | 298.4 | 98 | 246 | 4 | 4.5 | 8 | 8-222 | 21.19 | 21.57 |
| 10" | 267 | 406 | 31 | 362 | 98 | 305 | 4.5 | 5.5 | 8 | 12-25.4 | 29.52 | 30.47 |
| 12" | 323.9 | 483 | 35 | 431.8 | 98 | 365 | 5.5 | 7 | 8 | 12-25.4 | 44.77 | 46.56 |
| 14" | 368 | 533 | 41 | 476.2 | 99 | 400 | 6.5 | 8 | 8 | 12-28.6 | 57.52 | 59.49 |
| 16" | 419 | 597 | 43 | 539.8 | 106 | 457 | 7 | 9 | 8 | 16-28.6 | 74.10 | 78.03 |
| 18" | 457.2 | 635 | 45 | 577.8 | 113 | 505 | 8 | 9.5 | 8 | 16-31.8 | 88.16 | 91.08 |
| 20" | 508 | 698 | 45 | 635 | 118 | 559 | 8.5 | 11 | 8 | 20-31.8 | 106.20 | 110.65 |
| 24" | 610 | 813 | 49 | 749.3 | 137 | 664 | 10.5 | 13 | 8 | 20-34.9 | 153.15 | 160.79 |
| 28" | 711 | 927 | 72 | 864 | 145 | 748 | 12 | 15 | 8 | 28-34.9 | 255.28 | 249.09 |
| 32" | 813 | 1060 | 72 | 978 | 160 | 876 | 13.5 | 17 | 8 | 28-41.1 | 291.45 | 303.95 |
| 36" | 914 | 1168 | 72 | 1086 | 175 | 984 | 15.5 | 19 | 8 | 32-41.1 | 356.45 | 371.80 |
Frequently Asked Questions
What is the difference between a weld neck and a slip-on flange?
A weld neck flange connects to the pipe through a butt weld at its tapered hub. A slip-on flange fits over the pipe and is typically attached with fillet welds. Weld neck designs are often selected where joint geometry, inspection requirements and cyclic loading are important, but the final choice depends on the piping design.
Are Class 150 copper nickel flanges rated for 150 psi?
No. “Class 150” is a pressure-class designation, not a universal 150 psi working-pressure limit. The allowable pressure must be established using the applicable material, temperature and design requirements.
Can a 70/30 flange replace a 90/10 flange?
Not automatically. Confirm the material specification, mechanical requirements, welding procedure and project approval before making a substitution. Similar dimensions do not make two materials interchangeable.
What copper nickel alloys are available for weld neck flanges?
Common options include UNS C70600 90/10 copper nickel and UNS C71500 70/30 copper nickel. The appropriate grade depends on the piping specification, mechanical requirements and service environment.
Can copper nickel weld neck flanges be supplied to ASME B16.5?
Yes. HC Aluminum can supply weld neck flanges with dimensions and pressure class requirements based on ASME B16.5 where the standard is specified for the project. The material grade and service temperature should also be confirmed because the flange standard and material specification work together.
What information is required to quote a copper nickel weld neck flange?
Please provide the alloy, pipe size, pressure class, facing, bore or pipe wall requirement, quantity, applicable standard and any inspection or certification requirements. Drawings are recommended for non-standard dimensions.
The following copper nickel products may interest you
Further reading: Copper Nickel PipesCopper Nickel ElbowsCopper Nickel TeesCopper Nickel ReducerCopper Nickel Pipe CapCopper Nickel FlangesCopper Nickel Threaded Pipe Fittings