R30021 Cobalt vs. SAE-AISI D7 Steel

R30021 cobalt belongs to the cobalt alloys classification, while SAE-AISI D7 steel belongs to the iron alloys. There are 20 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.

For each property being compared, the top bar is R30021 cobalt and the bottom bar is SAE-AISI D7 steel.

UNS R30021 Co-Cr-W Alloy SAE-AISI D7 (T30407) Chromium Cold-Work Steel

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		220
Elastic (Young's, Tensile) Modulus, GPa		190

Poisson's Ratio		0.29
Poisson's Ratio		0.28

Shear Modulus, GPa		86
Shear Modulus, GPa		73

Tensile Strength: Ultimate (UTS), MPa		700
Tensile Strength: Ultimate (UTS), MPa		800 to 2120

Thermal Properties

Latent Heat of Fusion, J/g		330
Latent Heat of Fusion, J/g		270

Melting Completion (Liquidus), °C		1350
Melting Completion (Liquidus), °C		1440

Melting Onset (Solidus), °C		1190
Melting Onset (Solidus), °C		1400

Specific Heat Capacity, J/kg-K		450
Specific Heat Capacity, J/kg-K		480

Thermal Conductivity, W/m-K		15
Thermal Conductivity, W/m-K		27

Thermal Expansion, µm/m-K		11
Thermal Expansion, µm/m-K		11

Otherwise Unclassified Properties

Density, g/cm³		8.4
Density, g/cm³		7.6

Embodied Carbon, kg CO₂/kg material		8.0
Embodied Carbon, kg CO₂/kg material		11

Embodied Energy, MJ/kg		110
Embodied Energy, MJ/kg		180

Embodied Water, L/kg		520
Embodied Water, L/kg		130

Common Calculations

Stiffness to Weight: Axial, points		15
Stiffness to Weight: Axial, points		14

Stiffness to Weight: Bending, points		24
Stiffness to Weight: Bending, points		25

Strength to Weight: Axial, points		23
Strength to Weight: Axial, points		29 to 78

Strength to Weight: Bending, points		21
Strength to Weight: Bending, points		25 to 48

Thermal Diffusivity, mm²/s		3.8
Thermal Diffusivity, mm²/s		7.4

Thermal Shock Resistance, points		21
Thermal Shock Resistance, points		27 to 72

Alloy Composition

Carbon (C), %		0.2 to 0.35
Carbon (C), %		2.2 to 2.5

Chromium (Cr), %		26 to 29
Chromium (Cr), %		11.5 to 13.5

Cobalt (Co), %		61.7 to 67.3
Cobalt (Co), %		0

Copper (Cu), %		0
Copper (Cu), %		0 to 0.25

Iron (Fe), %		0 to 3.0
Iron (Fe), %		76.6 to 81.9

Manganese (Mn), %		0
Manganese (Mn), %		0 to 0.6

Molybdenum (Mo), %		4.5 to 6.0
Molybdenum (Mo), %		0.7 to 1.2

Nickel (Ni), %		2.0 to 3.0
Nickel (Ni), %		0 to 0.3

Phosphorus (P), %		0
Phosphorus (P), %		0 to 0.030

Silicon (Si), %		0 to 1.5
Silicon (Si), %		0 to 0.6

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

Vanadium (V), %		0
Vanadium (V), %		3.8 to 4.4