SAE-AISI D7 Steel vs. R30021 Cobalt

SAE-AISI D7 steel belongs to the iron alloys classification, while R30021 cobalt belongs to the cobalt 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 SAE-AISI D7 steel and the bottom bar is R30021 cobalt.

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

Metric UnitsUS Customary Units

Mechanical Properties

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

Poisson's Ratio		0.28
Poisson's Ratio		0.29

Shear Modulus, GPa		73
Shear Modulus, GPa		86

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

Thermal Properties

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

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

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

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

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

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

Otherwise Unclassified Properties

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

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

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

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

Common Calculations

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

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

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

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

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

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

Alloy Composition

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

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

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

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

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

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

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

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

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

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

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

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