ASTM B466/B466M is the standard specification by ASTM International covering seamless copper-nickel pipe and tube in UNS C70600 (Cu-Ni 90/10) and UNS C71500 (Cu-Ni 70/30). These copper-nickel alloys provide exceptional resistance to seawater corrosion, biofouling, and chloride attack with excellent thermal conductivity — making them the default material for marine piping, shipbuilding, and desalination plants worldwide. The companion specification ASME SB466 adopts identical requirements for ASME Code-stamped pressure equipment.

Zhengzhou Huitong (HT Pipe) supplies ASTM B466 / ASME SB466 compliant seamless pipe & tube with full Mill Test Certificates (MTC) per EN 10204 3.1. 

1. Standard Scope & Designation

ASTM B466/B466M covers seamless copper-nickel pipe and tube in straight lengths and U-bends for general engineering, marine, and heat exchanger applications. The specification includes C70600 (Cu-Ni 90/10) — the most widely used marine piping alloy — and C71500 (Cu-Ni 70/30) for condenser and heat exchanger service.

2. Grades Covered by ASTM B466

ASTM B466 covers the following grades. Each grade is defined by its UNS number and specific chemistry targeted at different service environments.

3. Chemical Composition

Values are weight percent maximum unless shown as a range. Heat analysis. Per ASTM B466 Table 1.

4. Mechanical Property Requirements

All values are minimum requirements. Tensile testing per ASTM E8/E8M.

5. Heat Treatment Requirements

6. Testing & Inspection Requirements

7. Dimensions & Dimensional Tolerances

ASTM B466 covers seamless copper-nickel pipe in sizes NPS 1/8 to NPS 12 (DN 6–300) and tube in OD 3/8"–12" (9.5–305 mm). Wall thickness: pipe per ASME B36.10M/B36.19M schedules or regular/extra-strong; tube per ASTM B251 decimal or BWG. Standard lengths: 6 m (20 ft) random or double random 12 m (40 ft). Also available in U-bend form for heat exchangers.

8. Industries & Applications

9. ASTM B466 vs ASTM B111 (Copper Alloy Seamless Condenser & Heat Exchanger Tubes) — Comparison

10. Related Standards

11. How to Order — Required Information

12. Frequently Asked Questions

Q: What is the difference between C70600 (90/10) and C71500 (70/30) Cu-Ni?

C70600 (90/10 — 90% Cu, 10% Ni) contains 1.0–1.8% Fe as the primary strengthener and is the standard marine piping alloy due to its excellent workability, weldability, and corrosion resistance at moderate cost. C71500 (70/30 — 70% Cu, 30% Ni) has higher Ni content (29–33%) with 0.40–1.0% Fe, giving it higher strength (YS 125 vs 105 MPa annealed), greater resistance to erosion-corrosion at high flow velocities (> 3.5 m/s), and superior performance in polluted or sulfide-contaminated seawater. C70600 handles most standard seawater applications; C71500 is specified for high-velocity, sulfide-bearing, or elevated-temperature seawater service, and for steam surface condenser tubes.

Q: Why is Cu-Ni the standard for shipboard seawater piping?

C70600 (90/10) Cu-Ni pipe offers a unique combination of: (1) natural biofouling resistance — the copper ion release inhibits marine organism attachment without toxic coatings; (2) excellent corrosion resistance at seawater flow velocities up to 2.5–3.0 m/s (8–10 ft/s); (3) inherent immunity to chloride SCC; (4) good weldability with matching Ni-Cu filler; (5) 40+ year proven service life in naval vessels; (6) no requirement for external coating or cathodic protection in most applications. These properties make C70600 the default material per MIL-T-16420K for US Navy and commercial shipbuilding seawater piping systems.

Q: Can ASTM B466 Cu-Ni pipe be welded?

Yes. Cu-Ni pipe is readily weldable by GTAW (TIG), GMAW (MIG), and SMAW processes. Recommended filler metals: ERCuNi (AWS A5.7 / ECuNi) for TIG/MIG; ECuNi for SMAW — these fillers contain ~30% Ni with Ti deoxidizer to ensure sound, porosity-free welds. Key procedure requirements: (1) joint cleanliness is critical — degrease and wire-brush; (2) 70/30 filler is used for both 90/10 and 70/30 base metals (slight over-alloying compensates for dilution); (3) no preheat required; (4) interpass temperature ≤ 65°C (150°F) to avoid hot cracking; (5) post-weld heat treatment is not required for C70600/C71500. The as-welded zone retains excellent seawater corrosion resistance.

Q: What is the maximum service temperature for ASTM B466 Cu-Ni pipe?

For continuous seawater service, C70600 (90/10) is recommended up to approximately 120°C (250°F) and C71500 (70/30) up to approximately 150°C (300°F). For general non-seawater service, both alloys can be used up to approximately 370°C (700°F) for C70600 and 420°C (788°F) for C71500, though mechanical properties begin to decrease above 200°C (400°F). For steam surface condenser service, C71500 tubes routinely operate at saturated steam temperatures (40–100°C / 100–210°F) with excellent performance. Cryogenic service is fully acceptable — Cu-Ni alloys retain excellent toughness and ductility to −196°C (−320°F).

Q: How does Cu-Ni compare to stainless steel for seawater piping?

Cu-Ni (C70600) has lower initial material cost than 316L stainless and approximately 5–8× lower cost than super-austenitics (AL-6XN) or duplex (2205). Cu-Ni provides natural biofouling resistance, while stainless steels require chlorination or antifouling coatings. Cu-Ni is immune to chloride SCC, while 316L fails SCC above ~60°C (140°F) in chlorides. Cu-Ni's maximum flow velocity (~3 m/s for C70600) is lower than super-duplex (> 20 m/s), but adequate for most shipboard and platform piping. Cu-Ni does not require post-weld passivation — stainless does. For standard marine piping < 3 m/s, C70600 is the cost-effective standard. For high-velocity, high-temperature, or sour service, super-duplex or Ni alloys are required.

Request a Quote — ASTM B466 Cu-Ni Seamless Pipe & Tube (C70600 & C71500)

Zhengzhou Huitong (HT Pipe) supplies ASTM B466 / SB466 C70600 (90/10) and C71500 (70/30) seamless copper-nickel pipe and tube for marine, desalination, and heat exchanger service. Full EN 10204 3.1 CMTRs with eddy current NDE per ASTM E243. Competitive lead times from qualified Cu-Ni tube mills.