ASTM A387 Grade 21 Steel vs. AWS BCo-1
ASTM A387 grade 21 steel belongs to the iron alloys classification, while AWS BCo-1 belongs to the cobalt alloys. There are 18 material properties with values for both materials. Properties with values for just one material (15, in this case) are not shown.
For each property being compared, the top bar is ASTM A387 grade 21 steel and the bottom bar is AWS BCo-1.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Poisson's Ratio | 0.29 | |
| 0.3 |
| Shear Modulus, GPa | 74 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 500 to 590 | |
| 700 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 420 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1150 |
| Melting Onset (Solidus), °C | 1430 | |
| 1120 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Expansion, µm/m-K | 13 | |
| 12 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.9 | |
| 8.1 |
| Embodied Carbon, kg CO2/kg material | 1.8 | |
| 8.0 |
| Embodied Energy, MJ/kg | 23 | |
| 110 |
| Embodied Water, L/kg | 62 | |
| 430 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 18 to 21 | |
| 24 |
| Strength to Weight: Bending, points | 18 to 20 | |
| 22 |
| Thermal Shock Resistance, points | 14 to 17 | |
| 21 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0 to 0.050 |
| Boron (B), % | 0 | |
| 0.7 to 0.9 |
| Carbon (C), % | 0.050 to 0.15 | |
| 0.35 to 0.45 |
| Chromium (Cr), % | 2.8 to 3.3 | |
| 18 to 20 |
| Cobalt (Co), % | 0 | |
| 46 to 54 |
| Iron (Fe), % | 94.4 to 96 | |
| 0 to 1.0 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0 |
| Molybdenum (Mo), % | 0.9 to 1.1 | |
| 0 |
| Nickel (Ni), % | 0 | |
| 16 to 18 |
| Phosphorus (P), % | 0 to 0.025 | |
| 0 to 0.020 |
| Selenium (Se), % | 0 | |
| 0 to 0.0050 |
| Silicon (Si), % | 0 to 0.5 | |
| 7.5 to 8.5 |
| Sulfur (S), % | 0 to 0.025 | |
| 0 to 0.020 |
| Titanium (Ti), % | 0 | |
| 0 to 0.050 |
| Tungsten (W), % | 0 | |
| 3.5 to 4.5 |
| Zirconium (Zr), % | 0 | |
| 0 to 0.050 |
| Residuals, % | 0 | |
| 0 to 0.5 |