Copper Alloys 12% Nickel Silver UNS-C75700

 Product Data Sheet – Copper Alloys

Copper Alloys Nickel Silver 12% Nickel Silver  UNS-C75700

Also known as Nickel Silver 65-12

Chemical Composition

AS2738-2000

Copper Lead Iron Nickel (inc Cobalt) Zinc
Minimum
60.0
11.0
Maximum
65.0
0.04
0.25
13.0
Remainder

 

Equivalent Alloy Specifications

Specification Designation
UNS
C75700
ISO
Cu Ni12 Zn24
BSI
NS104
JIS
NSP 3

Australian Product Specifications

Specification Product Form
AS1566
Rolled Flat Products

Fabrication Properties

Joining Technique Suitability
Soldering
Excellent
Brazing
Excellent
Oxy Acetylene Welding
Good
Gas Shielded Arc Welding
Fair
Coated Metal Arc Welding
Not Recommended
Resistance Welding (spot)
Good
Resistance Welding (seam)
Good
Fabrication Technique Suitability
Capacity for Being Cold Worked
Excellent
Capacity for Being Hot Worked
Very Limited
Hot Working Temperature
850-925°C
Annealing Temperature
600-750°C
Stress Relieving Temperature
250-350°C
Machinability Rating
25% of Free Cutting Brass
Polishing/Electroplating Finish
Excellent

Mechanical Properties

AS1566 Rolled Flat Products

Product
Temper
Tensile Strength Typical
Elongation Hardness
MPa
% HV
Coil & Flats
(Annealed)
400
48
(<100)
Coil & Flats
1/2 Hard
500
20
140-170
Coil & Flats
Hard
650
10
170-190
Coil & Flats
EH
750
4
195-220

Copper Alloys Nickel Silver C75700

Available Forms Austral Wright Metals can supply this alloy as coil or sheet. See the Austral Wright Metals Product Catalogue for standard stock sizes.

General Description 12% nickel silver takes a brilliant polish and has good resistance to corrosion in rural, industrial and marine atmospheres and in fresh water. Since it has good cold formability and an attractive soft ivory-white colour, it is often used for decorative applications.

The alloy is often silver plated, when it may be stamped EPNS (electro plated nickel silver). Alloy C75700 itself does not contain silver. It takes its name from the similarity of its appearance when polished to silver, although it does not have the corrosion resistance of the latter.

C75700 is a copper nickel zinc alloy. The crystal structure is the face centred cubic alpha phase, and hence the alloy has a good combination of strength, hardness and ductility.

Typical Uses

Decorative. Holloware, spoons and forks, watch cases, jewellery, medallions, “objets d’art”, pressed, spun or deep drawn items, usually silver plated.
Electrical. Relay & contact springs, wiper blades, resistance wire & strip for moderately elevated temperatures, contacts, connector pins & terminals.
Mechanical. Springs & clips, rivets, Bourdon tubing.
Miscellaneous. Instrument & camera parts, slide fasteners, etching stock, nameplates, musical instruments, fishing tackle, spectacle parts, latch keys, shop fittings.

 

 

Physical Properties

Property
Metric Units
Imperial Units
Melting Point (Liquidus)
1060°C
1940°F
Melting Point (Solidus)
1000°C
1830°F
Density
8.65 gm/cm³ @ 20°C
0.315 lb/in³ @ 68°F
Specific Gravity
8.65
8.65
Coefficient of Thermal Expansion
16.0 x 10 -6 / °C (20-300°C)
9.0 x 10 -5 / °F (68-392°F)
Themal Conductivity
80 W/m. °K @ 20°C
19 BTU/ft³/ft/hr/°F @ 68°F
Thermal Capacity (Specific Heat)
0.4184 J/kg. °K @ 20°C
0.10 BTU/lb/°F @ 68°F
Electrical Conductivity (Annealed)
0.0464 microhm-1.cm-1 @ 20°C
8% IACS @ 68°F
Electrical Resistivity (Annealed)
22 microhm.cm @ 20°C
130 ohms (circ mil/ft) @ 68°F
Temperature Coefficient of Electrical Resistance (Annealed)
0.0004 / °C @ 0-100°C
0.0002 / °F @ 32-212°F
Modulus of Elasticity (tension)
128.5 GPa @ 20°C
18.6 x 106 psi @ 68°F
Modulus of Rigidity (torsion)
48 GPa @ 20°C
6.9 x 106 psi @ 68°F
Poisson’s Ratio
0.35
0.35

 

Phase Diagram of C75700

Isothermal Section at 20°C

Copper Alloys 12% Nickel Silver UNS-C75700 Phase

Corrosion Resistance

C75700 has good corrosion resistance to weathering. It is frequently used in decorative applications, where it undergoes little tarnishing in service. If atmospheric corrosion does occur after prolonged exposure without cleaning in an aggressive marine environment, the corrosion products are likely to be green to brown in colour. Exposure tests 25 metres from a surf beach have indicated a likely thickness loss due to corrosion of about 1 mm per year

C75700 should not be used in contact with ammonia or ammonia compounds, as it may suffer stress corrosion cracking. Beware of corrosion inhibitors in piping systems containing carbon steels, which should be checked for compatibility with alloy C75700.

Please consult Austral Wright Metals for advice on your specific application.

The technical advice and recommendations made in this Product Data Sheet should not be relied or acted upon without conducting your own further investigations, including corrosion exposure tests where needed. Please consult current editions of standards for design properties. Austral Wright Metals assumes no liability in connection with the information in this Product Data Sheet. Austral Wright Metals supplies a comprehensive range of stainless steels, copper alloys, nickel alloys and other high performance metals for challenging service conditions. Our engineers and metallurgists will be pleased to provide further data and applications advice.

 

BACK