Copper Nickel 30% Alloy (C71500) suppliers

C71500 Copper Nickel 30% Alloy offers excellent corrosion resistance, stress corrosion cracking resistance, moderately high strength and good creep resistance at elevated temperatures. C71500 contains 30% nickel and is best suited for applications in areas of high temperatures and pressures combined with high velocity and turbulence.

C71500 Copper Nickel 30% Alloy is typically used for:

Condensers, boiler parts, heat exchanger components, condenser components, process equipment, refrigerators, propeller sleeves, ferrules, heat exchanger tubes, evaporator tubes, distiller tubes, condenser plates, weld wire, flexible metal hose, pump impellers, welding backing rings, valve bodies, sea water service, sea water condensers, salt water pipe fittings, water boxes – salt water applications, salt water flanges, salt water piping, pump bodies and internal parts-sea water, and fittings.

Highest corrosion resistance among copper alloys – Withstands seawater, brackish water, and acidic environments better than any other copper-based alloy.

Stress corrosion cracking immunity – Unlike 304/316 stainless steel, C71500 does not suffer from chloride stress corrosion cracking in warm seawater.

High temperature capability – Retains strength and creep resistance at elevated temperatures, suitable for boiler parts and heat exchangers.

High velocity and turbulence tolerance – Handles seawater flow up to 4-5 m/s without erosion damage. Best suited for high temperatures and pressures combined with high velocity and turbulence.

Biofouling resistance – Copper content prevents marine growth attachment, reducing maintenance in long-term seawater exposure.

Good fabricability – Can be welded, brazed, soldered, forged, and machined into complex shapes like valve bodies, pump impellers, and condenser plates.

Recommendation:

Choose C71500 for: high-velocity seawater (>3 m/s), high-temperature service (boilers, feedwater heaters), turbulent flow conditions, chloride stress corrosion cracking concerns, demanding marine and offshore applications.

Choose C70600 for: lower velocity seawater, fresh water cooling, general marine use where strength requirements are moderate, budget-sensitive projects.

Q1: C71500 vs C70600 – which one is stronger?

C71500 is significantly stronger. It contains 30% nickel while C70600 contains only 10% nickel. C71500 tensile strength ranges from 372 to 552 MPa, compared to 275-414 MPa for C70600. For high-pressure systems or high-temperature applications like boiler parts and feedwater heaters, C71500 is the better choice.

Q2: What is C71500 best suited for?

C71500 is best suited for high temperatures, high pressure, high velocity, and turbulent seawater conditions. Typical applications include condensers, heat exchangers, boiler parts, seawater piping, and pump components. The alloy handles aggressive salt water environments better than any other copper-based alloy.

Q3: Can C71500 be welded?

Yes, C71500 can be welded using gas shielded arc welding (TIG/MIG), coated metal arc welding, spot welding, seam welding, and butt welding. Brazing and soldering are also excellent options. For critical seawater service, use ERNi-7 filler metal and argon back-purge to prevent oxidation of the root pass.

Q4: What forms does C71500 come in?

C71500 is available as rings, discs, bars, rods, and plates from this supplier. Other common forms include seamless pipe (ASTM B466), seamless tube (ASTM B111), forgings, and wire. Custom shapes can be cast or forged to customer specifications.

Q5: Does C71500 resist stress corrosion cracking?

Yes, C71500 offers excellent resistance to stress corrosion cracking. This is a key advantage over 304 and 316 stainless steel, which can fail by chloride stress corrosion cracking in warm seawater. For marine environments with chlorides, C71500 is a reliable alternative.

Q6: What is the machinability of C71500?

C71500 machinability rating is 20, compared to free-cutting brass at 100. This means the alloy is relatively difficult to machine. Use sharp carbide tooling, low cutting speeds (below 50 m/min), and abundant oil-based coolant. For complex components, consider ordering finished machined parts.

Q7: Is C71500 used for pump impellers?

Yes, pump impellers are a common application for C71500. The alloy is also used for pump bodies and internal seawater parts. Its corrosion resistance and good creep resistance at elevated temperatures make it suitable for demanding pump applications in marine environments.

Q8: What is the density of C71500 for weight calculation?

C71500 density is 0.323 lb/in³ (8.94 g/cm³). For pipe weight calculation: (OD - wall) × wall × 10.68 = lb per foot. For a 1" OD × 0.065" wall pipe, weight is approximately 0.65 lb per foot. For plate: 1" thick plate weighs 46.5 lb per square foot.

Q9: Is C71500 used for boiler parts?

Yes, C71500 is used for boiler parts, condensers, and heat exchanger components. The alloy offers good creep resistance at elevated temperatures and high resistance to stress corrosion cracking. These properties make C71500 suitable for boiler components operating under high temperature and pressure in power plants.

Q10: What marine applications use C71500?

C71500 is used for sea water condensers, salt water piping, salt water flanges, salt water pipe fittings, water boxes, pump bodies, and internal seawater parts. The alloy's excellent corrosion resistance and biofouling resistance make it ideal for all these salt water applications. For aggressive marine environments with high velocity and turbulence, C71500 is a preferred material.

Chemical Verification:
Every batch of C71500 is tested by optical emission spectrometry to verify composition: Ni 30% nominal, Fe 0.4-1.0%, Cu balance.

Mechanical Testing:
Tensile and hardness tests confirm that C71500 meets the required strength properties for condensers, boiler parts, and pump components.

Dimensional Inspection:
Rings, discs, bars, rods, and plates are checked against customer specifications before shipment.

Traceability:
All test reports are linked to heat numbers and retained for full material traceability.

Pipe protection: Each C71500 copper pipe is capped with plastic end caps on both ends to prevent debris entry and edge damage.

Bundling: Pipes are formed into hexagonal bundles with steel straps applied every 1.5 meters. Plywood separators are placed between each layer to prevent surface scratching.

Bundle weight limit: Each bundle is kept under 2000 kg (4400 lbs) for safe handling.

Crate packaging for cut lengths: When pipes are cut to shorter lengths, they are packed into ISPM-15 certified wooden crates with foam lining inside.

Coiled pipe packaging: Long-length coiled pipe is wound onto steel reels. The reel flange is marked with heat number, size, and total length.

Labeling on every bundle: Alloy (C71500 70/30), heat number, OD × wall thickness, length, quantity, PO number, net weight, and gross weight are clearly marked.

Moisture control for sea freight: Desiccant bags are placed inside a moisture-barrier plastic liner for shipments to tropical destinations or when storage exceeds 6 months.

Melting: Induction furnaces with argon stirring. Composition controlled to Ni 29-33%, Fe 0.4-1.0%, Cu balance.

Casting: Horizontal continuous caster produces 200mm diameter billet specifically for tube extrusion.

Extrusion: 3500 ton extrusion press pierces the billet to form a hollow shell (tube blank).

Cold pilgering: Multiple pilger mill stands reduce OD and wall thickness. Can reduce OD by up to 75% in a single pass. Maximum tube length after pilgering is 40 meters.

Drawing: Draw benches of 30 ton and 60 ton capacity perform final sizing. Internal surface finish is smoothed to Ra 0.4 µm or better. Straightness after drawing is 0.5 mm per meter.

Annealing: Car bottom furnace operating at 650-815°C (1200-1500°F) with rapid water quench. Produces O61 annealed temper for maximum ductility.

Stress relieving: Lower temperature furnace produces HR50 drawn and stress relieved temper for higher strength.

Straightening: 6-roll rotary straighteners correct bending from drawing process. Achieves straightness of 0.5 mm per meter.

Testing: 100% eddy current tester (rotating probe) detects pinholes, slivers, and wall variations. Hydrostatic tester at 6000 psi checks each tube for leaks.

Inspection lab: OES spectrometer for composition, universal tensile tester, hardness tester, and metallurgical microscopes.

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