C76200 (ASTM B122) Alloy Data Specifications

Born of necessity during war years, C762 was developed to conserve nickel for national defense. Principally used for electrical relay springs and contact spring this alloy offers a unique combination of stiffness and strength required for such applications. Its work-hardening rate is high compared to other copper alloys, which is especially valuable when the functional strength of a part must be raised during forming. C762 also offer an attractive nickel silver color that can be used in decorative applications. For more information contact Olin Brass Market Development Engineering at 618-258-5255, OlinBrass.com or email us at info@olinbrass.com.

Chemical Composition

Copper1 57.0-61.0%
Nickel2 11.0-13.5%
Zinc Remainder
Iron 0.25% max
Lead 0.09% max

1Copper includes Ag; Copper plus named elements, 99.5%

2Nickel values includes Co

Physical Properties

  English Units Metrics Units
Density 0.310 lb/in3 @ 68oF 8.58 g/cm3
Thermal Conductivity 24 BTU-ft/ft2-hr-oF 41.5 W/moK
Electrical Resistivity 115 ohm circ mils/ft 19 microhm-cm
Electrical Conductivity (annealed) 9% IACS* 0.05 megamho/cm
Modulus of Elasticity 18,000,000 psi 124 kN/mm2
Thermal Capacity (Specific Heat) 0.090 Btu/lb/Fo @68oF 377.1 J/kg - oC @20oC
Coeff. of Thermal Expansion
  68-572oF (20-300oC) 9.0 oF 16.2 oC

Mechanical Properties

Temper1 Tensile Strength Yield Strength2 % Elongation2 Typical 90o Bend Formability GW/BW3
ksi N/mm2 ksi N/mm2
Annealed 57-75 395-515 36 250 40 - -
1/4 Hard 65-81 450-560 52 360 35 1.0 1.0
1/2 Hard 75-91 515-625 70 485 18 1.3 1.3
3/4 Hard 83-98 570-675 82 565 10 1.5 1.5
Hard 90-105 620-725 89 615 4 2.0 2.0
Extra Hard 101-114 695-785 98 675 2 2.5 2.5
Spring 109-122 750-840 105 725 1 max 3.0 3.0
Extra Spring 114 min 785 min 102 min 705 min 1 max

1Mechanical properties subject to change. All tempers listed are made to a Tensile Strength specification unless otherwise noted.
2Nominal Values

3DATA FOR REFERENCE ONLY. R/T = Bend Radius/Material Thickness <0.016" (0.4mm) thick, 11/16 (17.5mm) wide.