Strength and Performance in Extreme Environments
70/30 Cupro-Nickel (C71500 CuNi) is a high-strength copper nickel alloy recognized for its superior resistance to corrosion, erosion, and stress cracking in seawater and marine environments. With higher nickel content than 90/10, it offers enhanced mechanical strength and exceptional stability in turbulent or high-velocity seawater. The addition of iron and manganese improves overall performance and durability. C71500 is easily fabricated, welded, and formed, making it ideal for tubing, condensers, heat exchangers, and desalination systems. Combining strength, corrosion resistance, and reliability, 70/30 Copper Nickel is the trusted choice for demanding marine, offshore, and industrial applications requiring long-term performance.
Available Shapes for C71500 70/30 Copper Nickel
Plate
Sheet
Bar
Pipe
Tube
Casting
Forging
Flange
Applications for C71500 70/30 Copper Nickel
Condensers
Evaporators
Fire Suppression Systems
Heat Exchangers
Impellers
Pumps
Tubesheets
Valve Parts
Specifications
| Product Form | ASTM | ASME | Military |
|---|---|---|---|
| Bar | ASTM B151 | ASME SB-151 | MIL-C-15726 |
| Forging | - | - | MIL-C-24679 |
| Sheet | ASTM B171 | ASME SB-171 | MIL-C-15726 |
| Plate | ASTM B171 | ASME SB-171 | MIL-C-15726 |
| Pipe | ASTM B466 | ASME SB-466 | MIL-T-16420 |
| Tube | ASTM B111 | ASME SB-111 | MIL-T-15005 |
c71500 mechanical properties
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O60 | up to 1/2" | 52 | 18 | 30 |
| O60 | over 1/2" to 1" | 48 | 18 | 30 |
| O60 | over 1" | 45 | 18 | 30 |
| H01 | up to 1/2" | 65 | 50 | 10 |
| H01 | over 1/2" to 1" | 60 | 45 | 15 |
| H01 | over 1" to 3" | 55 | 35 | 20 |
| H01 | over 3" to 5" | 45 | 18 | 20 |
MIL-C-15726
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O60 | All Sizes | 45 | 18 | 30 |
| H01 | up to 1/2" | 65 | 50 | 10 |
| H01 | over 1/2" to 1" | 60 | 45 | 15 |
| H01 | over 1" to 3" | 55 | 35 | 20 |
c71500 mechanical properties
Commercial
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| M20 / O25 | up to 2-1/2" | 50 | 20 | 30 |
| M20 / O25 | over 2-1/2" | 45 | 18 | 30 |
MIL-C-15726
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O60 | up to 3/16" | 50 | 20 | 30 |
| M20 Soft | over 3/16" to 2-1/2" | 50 | 20 | 30 |
| M20 Soft | over 2-1/2" | 45 | 18 | 35 |
| H01 | up to 3/16" x 24" wide | 60 | 30 | 10 |
| H01 | up to 3/16" x over 24" wide | 55 | 25 | 10 |
| M20 Hard | up to 1/2" x over 24" wide | 50 | 22 | 15 |
| M20 Hard | over 1/2" x all widths | 45 | 18 | 20 |
c71500 mechanical properties – Pipe
Commercial
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O60 | All Sizes | 52 | 18 | N/A |
| H80 | All Sizes | 70 | 45 | N/A |
MIL-T-16420
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O60 | up to 4-1/2" | 50 | 18 | 30 |
| O60 | over 4-1/2" | 50 | 16 | 30 |
c71500 mechanical properties – Tube
Commercial
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O61 | All Sizes | 52 | 18 | N/A |
MIL-T-15005
| Temper | Size | Tensile (ksi, min) | Yield @0.5% (ksi, min) | Elong % Min |
|---|---|---|---|---|
| O61 | All Sizes | 52 | 18 | N/A |
c71500 chemical composition
Commercial
| UNS No. | Cu+Ag | Ni+Co | Mn | Pb | Fe | Zn | P | S | C |
|---|---|---|---|---|---|---|---|---|---|
| C71500 | remainder | 29.0-33.0 | 1.0 max | 0.05a max | 0.40-1.0 | 1.0a | - | - | - |
| C71520 | 65.0 min | 29.0-33.0 | 1.0 max | 0.02 | 0.40-1.0 | 0.5 | 0.02 max | 0.02 max | 0.05 max |
MIL-C-15726 / MIL-T-16420 / MIL-T-15005
| UNS No. | Cu | Ni+Co | Mn | Pb | Fe | Zn | P | S | C | Cu+ (min) |
|---|---|---|---|---|---|---|---|---|---|---|
| C71500 | 65.0 min | 29.0-33.0 | 1.0 max | 0.02 max | 0.40-1.0 | 0.50 max | 0.02 max | 0.02 max | 0.05 max | 99.5 |
c71500 density and physical properties
| Property | Value |
|---|---|
| Density @ 68°F | 0.323 lb/in³ |
| Melting Range | 2140-2265°F |
| Hot Formability | Good |
| Cold Formability | Good |
| Machinability rating (C360 = 100) | 20 |
| Brazing | Excellent |
| Soldering | Excellent |
| Gas-shielded arc welding | Excellent |
| Oxy-acetylene welding | Good |
| Carbon-arc welding | Not recommended |
| Coated metal-arc welding | Good |
| Resistance welding: spot and seam | Good |
| Resistance Welding: butt | Good |
FAQ
Q1: What is the difference between C71500 and C70600 copper nickel?
C71500 has higher strength and better erosion resistance than C70600. C71500 contains 29-33% nickel with tensile strength 45-70 ksi (depending on temper). C70600 contains 9-11% nickel with lower strength. For high-velocity seawater, turbulent conditions, or higher pressure, choose C71500. For general marine use, C70600 is more economical.
Q2: What are the available shapes for C71500 material?
Plate, sheet, bar, pipe, tube, casting, forging, and flange. All these shapes are listed on the page as available for C71500 70/30 Copper Nickel.
Q3: What is the density of C71500 for weight calculation?
C71500 density is 0.323 lb/in³ at 68°F. For pipe weight: (OD - wall) × wall × 10.68 = lb/ft. This density contributes to pressure tightness and durability.
Q4: What welding methods are recommended for C71500?
Gas-shielded arc welding is Excellent; oxy-acetylene welding is Good; carbon-arc welding is Not recommended. Brazing and soldering are Excellent. Resistance welding (spot, seam, butt) is Good. For seawater pipe, use TIG welding with ERNi-7 filler and argon back-purge.
Q5: What is the machinability rating of 70/30 copper nickel?
Machinability rating is 20 (C360 free-cutting brass = 100). For bar in H01 temper, tensile is 55-65 ksi with yield 35-50 ksi – this half-hard temper machines better than annealed. Use sharp carbide tools, lower speeds, and abundant coolant.
Q6: What are the military specifications for C71500 pipe?
MIL-T-16420 for pipe. For tube: MIL-T-15005. For sheet/plate/bar: MIL-C-15726. For forging: MIL-C-24679. For naval applications, specify the correct MIL spec for your product form.
Q7: What is the melting range of C71500?
Melting range is 2140-2265°F (1171-1241°C). Hot formability is Good. This relatively high melting point allows C71500 to retain strength at elevated temperatures.
Q8: What are the common applications for C71500?
Condensers, evaporators, tubesheets, valve bodies, pump bodies, impellers, fire suppression systems, brake lines, heat exchangers, fasteners, fittings, and flanges. The page lists all these applications.
Q9: What is the difference between C71500 and C71520?
C71520 has tighter impurity limits for welding applications. C71520 requires Pb ≤0.02%, Zn ≤0.5%, P ≤0.02%, S ≤0.02%, C ≤0.05%. For subsequent welding, specify C71520. For non-welded applications, C71500 with max Pb 0.05 and Zn 1.0 is acceptable.
Q10: What tempers are available for C71500 pipe?
O60 (annealed) and H80 (drawn) for commercial pipe. O60 tensile is 52 ksi min, yield 18 ksi min. H80 tensile is 70 ksi min, yield 45 ksi min. For MIL-T-16420 pipe, O60 temper with 50 ksi tensile and 18 ksi yield (up to 4-1/2").
Detection & Quality Control
| Test Method | Purpose | Acceptance Criteria |
|---|---|---|
| Optical Emission Spectrometry | Verify c71500 chemical composition | Ni 29-33%, Fe 0.40-1.0%, Cu 65.0% min (per MIL spec) |
| Tensile Test | Confirm c71500 mechanical properties | O60 pipe: UTS ≥52 ksi (commercial) or ≥50 ksi (MIL), Yield ≥18 ksi |
| Hardness Test | Uniformity of temper | Per temper specification |
| Dimensional Check | OD, wall, length | Per ASTM B466 |
| Hydrostatic Test | Leak tightness | Per specification |
| Eddy Current Test (when specified) | Detect pits and wall variations | Per ASTM E243 |
Packaging
c71500 copper pipe is packaged to prevent damage during transit:
| Packaging Type | Details |
|---|---|
| Hexagonal bundles | Steel straps, plywood separators, plastic end caps. Max bundle weight 2000 kg. |
| Wooden crates | ISPM-15 certified, foam-lined for finished components. |
| Steel reels | For coiled tube. Marked with heat number, size, length. |
Marking per bundle: Alloy (C71500 / 70/30), heat number, size (OD × wall), length, quantity, PO number, net/gross weight.
Moisture protection: Desiccant bags for tropical or long-term storage.
Factory Equipment
| Equipment | |
|---|---|
| Induction melting furnaces | Precise control of Ni 29-33%, Fe 0.40-1.0%, Cu 65.0% min |
| Continuous caster | Produces solid billet |
| Extrusion press | Pierces billet to hollow shell |
| Cold pilger mills | Reduces OD and wall thickness |
| Draw benches | Final sizing, smooth finish |
| Annealing furnaces | O60 / O61 temper production |
| Stress relieving furnaces | H80 temper production |
| Straightening machines | Achieves straightness |
| Hydrostatic testers | Pressure testing |
| Metallurgical lab | OES, tensile, hardness verification |
Our Full Product Range
| Product Form | Common Standards | Typical Alloy Grades | Size Range | Typical Applications |
|---|---|---|---|---|
| Copper Pipe & Tube | ASTM B111, B466, ASME SB111, SB466, MIL-T-15005, MIL-T-16420 | C71500, C70600, C12200, C68700, C44300 | Pipe: up to 12"; Tube: condenser sizes | Heat exchangers, condensers, seawater piping, fire suppression systems |
| Copper Bar (Round, Hex, Square) | ASTM B151, ASME SB151, MIL-C-15726 | C71500, C70600, C36000, C46400, C63000 | up to 5" diameter | Valve bodies, pump shafts, fasteners, impellers |
| Copper Sheet & Plate | ASTM B171, ASME SB171, MIL-C-15726 | C71500, C70600, C46400, C63000 | up to 2-1/2" thick | Tubesheets, condensers, evaporators, flanges |
| Copper Forging | MIL-C-24679 | C71500, C70600 | Custom | Valve parts, pump bodies, fittings |
| Copper Casting | Per specification | C71500, C70600 | Custom | Impellers, valve bodies, pump components |
| CNC Machined Components | Custom drawing | C71500, C70600, C36000, C63000, C17200 | Custom tolerances | Valve parts, pump components, custom fittings |
