ASTM B780 Alloy vs. R30155 Cobalt

ASTM B780 alloy belongs to the otherwise unclassified metals classification, while R30155 cobalt belongs to the iron alloys. There are 15 material properties with values for both materials. Properties with values for just one material (19, in this case) are not shown.

For each property being compared, the top bar is ASTM B780 alloy and the bottom bar is R30155 cobalt.

ASTM B780 Silver-Copper-Nickel Electrical Contact Alloy UNS R30155 (formerly Grade 661) Iron-Cobalt Alloy

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		83
Elastic (Young's, Tensile) Modulus, GPa		210

Elongation at Break, %		1.1 to 9.1
Elongation at Break, %		34

Poisson's Ratio		0.36
Poisson's Ratio		0.29

Shear Modulus, GPa		30
Shear Modulus, GPa		81

Shear Strength, MPa		200 to 340
Shear Strength, MPa		570

Tensile Strength: Ultimate (UTS), MPa		330 to 590
Tensile Strength: Ultimate (UTS), MPa		850

Thermal Properties

Latent Heat of Fusion, J/g		140
Latent Heat of Fusion, J/g		300

Specific Heat Capacity, J/kg-K		270
Specific Heat Capacity, J/kg-K		450

Thermal Expansion, µm/m-K		18
Thermal Expansion, µm/m-K		14

Otherwise Unclassified Properties

Density, g/cm³		10
Density, g/cm³		8.5

Common Calculations

Stiffness to Weight: Axial, points		4.5
Stiffness to Weight: Axial, points		14

Stiffness to Weight: Bending, points		14
Stiffness to Weight: Bending, points		23

Strength to Weight: Axial, points		9.1 to 16
Strength to Weight: Axial, points		28

Strength to Weight: Bending, points		11 to 15
Strength to Weight: Bending, points		24

Thermal Shock Resistance, points		16 to 29
Thermal Shock Resistance, points		21

Alloy Composition

Cadmium (Cd), %		0 to 0.050
Cadmium (Cd), %		0

Carbon (C), %		0
Carbon (C), %		0.080 to 0.16

Chromium (Cr), %		0
Chromium (Cr), %		20 to 22.5

Cobalt (Co), %		0
Cobalt (Co), %		18.5 to 21

Copper (Cu), %		23.5 to 25.7
Copper (Cu), %		0

Iron (Fe), %		0 to 0.050
Iron (Fe), %		24.3 to 36.2

Lead (Pb), %		0 to 0.030
Lead (Pb), %		0

Manganese (Mn), %		0
Manganese (Mn), %		1.0 to 2.0

Molybdenum (Mo), %		0
Molybdenum (Mo), %		2.5 to 3.5

Nickel (Ni), %		0.35 to 0.65
Nickel (Ni), %		19 to 21

Niobium (Nb), %		0
Niobium (Nb), %		0.75 to 1.3

Nitrogen (N), %		0
Nitrogen (N), %		0 to 0.2

Phosphorus (P), %		0
Phosphorus (P), %		0 to 0.040

Silicon (Si), %		0
Silicon (Si), %		0 to 1.0

Silver (Ag), %		74 to 76
Silver (Ag), %		0

Sulfur (S), %		0
Sulfur (S), %		0 to 0.030

Tantalum (Ta), %		0
Tantalum (Ta), %		0.75 to 1.3

Tungsten (W), %		0
Tungsten (W), %		2.0 to 3.0

Zinc (Zn), %		0 to 0.060
Zinc (Zn), %		0