MATERIAL COMPARISON
Start with the specified alloy, not the nickel percentage alone
CuNi 90/10 and 70/30 are copper-nickel families used in marine systems. The selection must fit the component and its operating environment. A higher nickel figure is not, by itself, permission to replace the specified grade.
Differences to verify
| Criterion | CuNi 90/10 | CuNi 70/30 |
|---|---|---|
| UNS identification | C70600 | C71500 |
| Nominal nickel, mass % | 10 % | 30 % |
| Relative strength: Nickel Institute overview | Lower of this pair | Higher of this pair |
Source for the nominal family values: CDA - Wrought Copper-Nickel Alloys (Revision 2026-05-13; page 3, C70600 and C71500; checked 2026-10-13, p. 3, C70600; note 3 on p.5).
Sources: Nickel Institute overview and composition reference. The relative strength statement is qualitative: product form, condition and the applicable specification are still required for numerical mechanical properties.
Nickel Institute | Nickel Institute: UNS / Ni
What should drive the choice?
Existing specification
For replacement work, start with the drawing and the actual material designation. Identify the mating components before requesting an alternative.
Operating environment
Describe the fluid and service conditions. Ask the responsible engineer to assess flow, temperature and compatibility for the actual arrangement rather than applying one universal limit.
Comparable offers
Keep alloy, supply form, dimensions and quantity aligned between offers. Use the existing inquiry notes or drawing upload to identify the component and intended service.
Limits of substitution
C70600 and C71500 are not interchangeable descriptions. Do not infer an allowable pressure, flow velocity or service life from this table. Substitution needs documented technical acceptance for the component and its joints; this page is not a design approval.
Technical Sources & Revision
The Nickel Institute public overview and composition page support the family identifiers and the qualitative distinction above. No publication date is shown on those pages. Selection questions are original MNK-G.S.A purchasing guidance, not an additional material standard.
Additional source check: 30 September 2026. Copper Alloys identifies C70600 as 90/10 and C71500 as 70/30; its Cupro-Nickels overview supports the qualitative strength distinction. No numerical strength limits are adopted here. Source publication dates are not stated.
Copper Alloys: C70600 | Copper Alloys: C71500 | Copper-nickel overview (English)
Materials and next steps
Technical review: 14 September 2026. Original purchasing guidance by MNK-G.S.A. Public references do not imply a supplier partnership.