Following 30 years of development, an established material has been given a new lease of life: copper-nickel-chrome, which has been in-service with critical systems for the Royal Navy is now available in wrought form.

 

Designed for submarine seawater systems, and to replace nickel-aluminium bronze (NAB), Def Stan 02-886 was released in February 2019. This means that there is now a realistic high integrity solution to corrosion that is elegant and cost effective.

 

This is exactly why the Ministry of Defence working with industry in the UK has spent millions of pounds over three decades developing the technology to make copper-nickel-chrome forgings.

 

Observations from over 25-years in-service experience combined with multiple Government bodies and UKAS approved testing facilities have found the following:

 

• Extended seawater fatigue and destructive tests carried out by the Australian and British Governments have found that by forging copper-nickel-chromium, it increases mechanical properties and its ability to resist corrosion. [Galsworthy, J. C., and Baxter, D., ‘Forged Copper-Nickel-Chromium Alloy for Seawater System Components’, 10th INCC Halifax, NS, 
Canada, April 1997]  
• 60 destructive mechanical tests carried out by a UKAS independent testing facility have found that Def Stan 02-886 is the toughest of all the copper alloys and is x5 more resistant to shock than NAB. [Gregory, S., Mechanical Properties of Wrought CNC, February 2019]
• Copper-nickel-chrome is a single-phase alloy, which means it does not suffer from selective phase corrosion. [Def Stan 02-886, Issue 1, UK MOD]
• Copper-nickel-chrome has been in service for over 20 years and resisted corrosion to an unprecedented extent, meaning it does not need to be replaced. [Ferrera, R. J., ‘Seawater corrosion behavior of copper-nickel alloys CA 719 and CA 715’, AMPTIAC document number AM025468, 
October 1978]
• The ability of Def Stan 02-886 to withstand crevice corrosion has been tested in the British Corrosion Project and performed the best of all copper-based alloys and is comparable to Titanium. [Richardson, I, ‘Wrought Copper-Nickel-Chrome: A New Concept for Corrosion Resistant Metals’, NACE Corrosion Symposia, Nashville, USA, March 2019]
• The British Corrosion Project also proved that it is galvanically compatible with existing systems, meaning that it does not have a detrimental effect on adjoining components. [Richardson, I, ‘Wrought Copper-Nickel-Chrome: A New Concept for Corrosion Resistant Metals’, NACE Corrosion Symposia, Nashville, USA, March 2019]
• Costing exercises carried out by a leading valve manufacturer have shown that an assembled valve made from Def Stan 02-886 is comparable in cost to the same valve made from NAB.
• An assembled and installed valve made from Def Stan 02-886 is designed to last the lifetime of the ship or submarine. The same valve made from NAB can be expected to be replaced up to five times over the lifetime of a submarine. [Def Stan 02-824, UK MOD, Page 4]

 

Production Reliability

The method of producing Def Stan 02-886 is based on reliable production processes that have been used to produce cupro-nickels, NAB, and nickel alloy forgings for decades.

It is common-place to have zero material defects over production of thousands of components because the very process of forging proves the integrity of the material and with the finer grain structure it is possible to be doubly sure by ultrasonic examination which is a precise and low-cost method of volumetric inspection.

 

Availability

Def Stan 02-886 is available now ex-stock and bespoke components can be produced within a matter of weeks.