70/30 is a 70% copper, 30% nickel alloy with additions of iron and manganese. These elemental additions make it somewhat more resistant to corrosion and erosion and with slightly improved strength level than 90/10, making it suitable for more demanding applications. In particular, its corrosion resistance is notably improved in high-velocity waters (up to 4.5m/s) and polluted seawater.
70/30 is readily cold worked, fabricated and welded without any special material considerations. The most popular specifications covering this alloy are the CN107 and C71500 designations, although the Defence Standard DEF STAN 02-879 Annex B (superseding DEF STAN 02-780 and NES 780) offers tighter controls on impurities and mechanical properties together with a mandatory impact value.
Related Specifications of 70/30
- DEF STAN 02-879 Annex B
- DEF STAN 02-780
- EN 12164
- ASTM B151
Nominal Composition of 70/30
Cu rem, Ni 30%, Fe 0.7%, Mn 1.0%
Mechanical Properties of 70/30
|Ultimate Tensile Strength (N/mm²)||Proof Stress (N/mm²)||Elongation (%)||Hardness (HB)|
Key Features of 70/30
- Excellent corrosion and pitting resistance in marine environments
- Good strength and toughness
- Resistance to biofouling
- Readily weldable and fabricated
Applications of 70/30
Offshore & marine | Salt water flanges, salt water piping and pipe fittings, valve bodies, sea water intakes, pipe fittings, water boxes, propeller sleeves, pump bodies and parts
Chemical processing | Heat exchanger and cooling plant, evaporator tubes, distiller tubes, refrigerator and condenser components
Other | Welding backing rings, flexible metal hose, weld wire and boiler parts
Columbia Metals – a leading supplier of 70/30
With decades of experience and a huge range of stock, Columbia Metals is an industry leader in the supply of 70/30 and other high quality specialist engineering alloys.
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