What is UN14A2 / NF L 14-702?
UN14A2, specified as NF L 14-702 and written CuNi14Al2 or CuNi14Al3, is a high strength cupro nickel aluminium alloy. Typical properties are 1000 N/mm² tensile strength, 750 N/mm² proof strength, 12 % elongation and 250 HB. It combines high tensile and fatigue strength with excellent corrosion resistance, strong wear performance and non-susceptibility to hydrogen embrittlement, and it can be precipitation hardened.
Should you specify UN14A2 / NF L 14-702?
Specify UN14A2 when you need strength well beyond nickel aluminium bronze but still need copper alloy corrosion behaviour in seawater. Typical tensile strength of 1000 N/mm² with 12 % elongation puts it in a class of its own among the copper alloys on this site.
It is the usual choice for marine fasteners because it is not susceptible to hydrogen embrittlement, and it is also used on lead connectors, stab plates, winches, actuator valves and seawater valves.
In aerospace it is used for landing gear bushes and sleeves, where wear resistance matters as much as strength. In high performance automotive it appears as valve guides and valve seats.
It can be precipitation hardened to achieve tensile properties close to beryllium copper, so it is worth pricing against beryllium copper where the toxicity and handling controls of that alloy are unwelcome. Confirm the heat treatment condition on the drawing before ordering.
Best for highly stressed marine fasteners, connectors and aerospace bushes where beryllium copper strength is wanted without the beryllium.
UN14A2 / NF L 14-702 quick reference
Typical, indicative values as published by Copper Alloys Ltd. Typical values are not specification limits, and vary with product form, section size and temper.
| Alloy type | Wrought - High strength cupro nickel aluminium (not a nickel aluminium bronze) |
|---|---|
| Nominal composition | CuNi14Al3 |
| Tensile strength (typical) | 1000 N/mm² |
| Proof / yield strength (typical) | 750 N/mm² |
| Elongation (typical) | 12 % |
| Hardness (typical) | 250 HB |
| Izod impact (typical) | 10 J at 20 °C |
UN14A2 / NF L 14-702 typical physical properties
Key features of UN14A2 / NF L 14-702
- High tensile and yield strength.
- Good fatigue resistance.
- Excellent corrosion resistance.
- Strong wear performance.
- Non-susceptibility to hydrogen embrittlement.
- Can be precipitation hardened for enhanced mechanical properties, close to beryllium copper.
UN14A2 / NF L 14-702 applications
Marine and naval
- Marine fasteners
- Lead connectors and stab plates
- Winches and actuator valves
- Seawater valves and general engineering
Aerospace
- Landing gear bushes
- Sleeves requiring high wear resistance
Automotive
- Valve guides
- Valve seats in high performance engines
UN14A2 / NF L 14-702 equivalent specifications
Frequently asked questions
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Information provided is for reference only
The composition, mechanical and physical figures on this page are typical, indicative values compiled from published Copper Alloys Ltd datasheets to aid early-stage material selection. They are not specification limits and are not engineering, procurement, safety, regulatory or design advice.
Before specifying, purchasing or using any material, confirm the requirements against the current controlled version of the relevant standard and obtain a certified material test report and written technical confirmation from Copper Alloys Ltd or another qualified foundry.