C63800 (ASTM B422) Coronze Alloy Data Specifications

Coronze, or Alloy C638 is a high strength, cost effective, cobalt-modified aluminum silicon bronze which was developed for its corrosion resistant properties, particularly its oxidation resistance at elevated temperatures. A number of superior qualities, including surface characteristics, formability, strength and conductivity, make C638 an excellent choice for use in a wide range of applications including electrical connectors and spring contacts. 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 Remainder
Aluminum 2.5-3.1%
Cobolt 0.25-2.1%
Silicon 1.5-2.1%
Iron 0.20% max
Lead 0.05% max
Manganese 0.10% max
Nickel 0.20% max
Zinc 0.8% max

1Copper plus named elements, 99.5% min

Physical Properties

  English Units Metrics Units
Density 0.299 lb/in3 @ 68oF 8.28 g/cm3
Thermal Conductivity 22.0 BTU-ft/ft2-hr-oF 38 W/moK
Electrical Resistivity 104 ohm circ mils/ft 17.4 microhm-cm
Electrical Conductivity (annealed) 10% IACS* 0.058 megamho/cm
Modulus of Elasticity 16,700,000 psi 115 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) 9.5 PPM/oF 17.1 PPM/oC

*International Annealed Copper Standard

Mechanical Properties

Temper1 Tensile Strength Yield Strength2 % Elongation2 Typical 90o Bend Formability GW/BW3
ksi N/mm2 ksi N/mm2
Annealed 77-87 530-600 56 385 33 - -
1/4 Hard 90-102 620-705 82 565 16 0.5 1.5
1/2 Hard 100-112 690-770 93 640 10 0.8 2.0
3/4 Hard 105-117 725-805 99 685 7 1.0 2.5
Hard 114-126 758-870 108 745 4 1.5 3.5
Extra Hard 118-130 815-895 112 770 3 2.3 4.5
Spring 123-134 850-925 116 800 2 3.0 7.0
Extra Spring 130 min 895 min 119 min 820 min 2 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.