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R30021 Cobalt vs. AISI 440B Stainless Steel

R30021 cobalt belongs to the cobalt alloys classification, while AISI 440B stainless steel belongs to the iron alloys. There are 26 material properties with values for both materials. Properties with values for just one material (8, in this case) are not shown.

For each property being compared, the top bar is R30021 cobalt and the bottom bar is AISI 440B stainless steel.

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa 220
200
Elongation at Break, % 9.0
3.0 to 18
Fatigue Strength, MPa 250
260 to 850
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 86
77
Tensile Strength: Ultimate (UTS), MPa 700
740 to 1930
Tensile Strength: Yield (Proof), MPa 500
430 to 1860

Thermal Properties

Latent Heat of Fusion, J/g 330
280
Melting Completion (Liquidus), °C 1350
1480
Melting Onset (Solidus), °C 1190
1370
Specific Heat Capacity, J/kg-K 450
480
Thermal Conductivity, W/m-K 15
23
Thermal Expansion, µm/m-K 11
10

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 1.9
2.5
Electrical Conductivity: Equal Weight (Specific), % IACS 2.1
2.9

Otherwise Unclassified Properties

Density, g/cm3 8.4
7.7
Embodied Carbon, kg CO2/kg material 8.0
2.2
Embodied Energy, MJ/kg 110
31
Embodied Water, L/kg 520
120

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 57
57 to 110
Stiffness to Weight: Axial, points 15
14
Stiffness to Weight: Bending, points 24
25
Strength to Weight: Axial, points 23
27 to 70
Strength to Weight: Bending, points 21
24 to 45
Thermal Diffusivity, mm2/s 3.8
6.1
Thermal Shock Resistance, points 21
27 to 70

Alloy Composition

Carbon (C), % 0.2 to 0.35
0.75 to 1.0
Chromium (Cr), % 26 to 29
16 to 18
Cobalt (Co), % 61.7 to 67.3
0
Iron (Fe), % 0 to 3.0
78.2 to 83.3
Manganese (Mn), % 0
0 to 1.0
Molybdenum (Mo), % 4.5 to 6.0
0 to 0.75
Nickel (Ni), % 2.0 to 3.0
0
Phosphorus (P), % 0
0 to 0.040
Silicon (Si), % 0 to 1.5
0 to 1.0
Sulfur (S), % 0
0 to 0.015