Technical guide · 2026-08-03
Copper-Nickel
Copper-nickel alloys combine copper with nickel for seawater corrosion and biofouling-related performance, strength and fabrication. The common 90-10 and 70-30 systems differ in alloy content and service capability; successful use still depends on flow, commissioning, water chemistry, deposits and system design.
01
Definition and boundary
Use exact UNS identity and wrought/cast product form; traditional family names alone are too broad for substitution or acceptance.
Reference information only: final acceptance is controlled by the ordered product specification, condition, dimensions and certified test results.
02
How the material system works
Alloying and processing trade conductivity against strength, wear, corrosion or softening resistance.
Temper or heat treatment sets final strength, formability and conductivity.
Environment, joining and galvanic contact can dominate service performance.
03
Representative grades and systems
| Grade or system | Selection focus | Qualification |
|---|---|---|
| C70600 | 90-10 copper-nickel widely used for seawater tube and piping. | Verify the ordered product specification, condition and dimensions before substitution. |
| C71500 | 70-30 copper-nickel for more demanding seawater and condenser service. | Verify the ordered product specification, condition and dimensions before substitution. |
| C71000 | Intermediate copper-nickel system for selected engineering products. | Verify the ordered product specification, condition and dimensions before substitution. |
04
Properties and trade-offs
Conductivity must be specified with test basis and temper where functional.
Strength and formability vary strongly with temper and product direction.
Corrosion suitability is system- and environment-specific.
05
Product forms and supply conditions
06
Applications and selection
Applications and selection
- Seawater piping and firewater systems
- Condensers, heat exchangers and desalination
- Marine brake, hydraulic and offshore tubing
Properties and trade-offs
- Define electrical/thermal, mechanical, corrosion, wear and regulatory priorities.
- Select exact UNS alloy, wrought/cast form and temper.
- Verify joining, plating, water chemistry and galvanic compatibility.
07
Fabrication, durability and inspection
Select forming, annealing, machining and joining practice for the exact alloy and temper.
Manage heat input and filler/flux choice to protect conductivity, strength and corrosion behavior.
Prevent contamination and verify post-process cleaning, pickling, passivation or plating compatibility.
08
Procurement checklist
- Use the five-digit UNS designation plus wrought/cast product specification, temper and dimensions.
- Specify conductivity, hardness, grain size, mechanical properties, surface and cleanliness where functional.
- State joining, plating, potable-water, pressure, marine or regulatory requirements and certificate traceability.
09
Standards, sources and review
Standards and designation context
- CDA/UNS registered alloy records
- Applicable ASTM B-series product specification
- Application pressure, electrical, marine or regulatory requirements
Authoritative research sources
Copper Development Association · UNS wrought and cast alloy records, accessed 2026
Copper Development Association · API 2.0.1
Copper Development Association · Technical portal, accessed 2026