AISI 420 Stainless Steel vs. R30008 Cobalt
AISI 420 stainless steel belongs to the iron alloys classification, while R30008 cobalt belongs to the cobalt alloys. They have a modest 29% of their average alloy composition in common, which, by itself, doesn't mean much. There are 23 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 AISI 420 stainless steel and the bottom bar is R30008 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 210 |
| Elongation at Break, % | 8.0 to 15 | |
| 1.1 to 73 |
| Fatigue Strength, MPa | 220 to 670 | |
| 320 to 530 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 76 | |
| 83 |
| Tensile Strength: Ultimate (UTS), MPa | 690 to 1720 | |
| 950 to 1700 |
| Tensile Strength: Yield (Proof), MPa | 380 to 1310 | |
| 500 to 1080 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 320 |
| Melting Completion (Liquidus), °C | 1510 | |
| 1400 |
| Melting Onset (Solidus), °C | 1450 | |
| 1330 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 450 |
| Thermal Expansion, µm/m-K | 10 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.5 | |
| 95 |
| Density, g/cm3 | 7.7 | |
| 8.4 |
| Embodied Carbon, kg CO2/kg material | 2.0 | |
| 8.1 |
| Embodied Energy, MJ/kg | 28 | |
| 110 |
| Embodied Water, L/kg | 100 | |
| 400 |
Common Calculations
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 380 to 4410 | |
| 590 to 2720 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 25 to 62 | |
| 31 to 56 |
| Strength to Weight: Bending, points | 22 to 41 | |
| 25 to 37 |
| Thermal Shock Resistance, points | 25 to 62 | |
| 25 to 44 |
Alloy Composition
| Boron (B), % | 0 | |
| 0 to 0.0010 |
| Carbon (C), % | 0.15 to 0.4 | |
| 0 to 0.15 |
| Chromium (Cr), % | 12 to 14 | |
| 18.5 to 21.5 |
| Cobalt (Co), % | 0 | |
| 39 to 42 |
| Iron (Fe), % | 82.3 to 87.9 | |
| 7.6 to 20 |
| Manganese (Mn), % | 0 to 1.0 | |
| 1.0 to 2.0 |
| Molybdenum (Mo), % | 0 to 0.5 | |
| 6.5 to 7.5 |
| Nickel (Ni), % | 0 to 0.75 | |
| 15 to 18 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.015 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.2 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.015 |