SAE-AISI P21 Steel vs. Ductile Cast Iron
Both SAE-AISI P21 steel and ductile cast iron are iron alloys. They have a moderately high 94% of their average alloy composition in common. There are 23 material properties with values for both materials. Properties with values for just one material (9, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI P21 steel and the bottom bar is ductile cast iron.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 170 to 180 |
| Poisson's Ratio | 0.29 | |
| 0.28 to 0.31 |
| Shear Modulus, GPa | 73 | |
| 64 to 70 |
| Tensile Strength: Ultimate (UTS), MPa | 1130 | |
| 460 to 920 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 270 |
| Melting Completion (Liquidus), °C | 1450 | |
| 1160 |
| Melting Onset (Solidus), °C | 1410 | |
| 1120 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 490 |
| Thermal Conductivity, W/m-K | 41 | |
| 31 to 36 |
| Thermal Expansion, µm/m-K | 12 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.9 | |
| 7.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 9.0 | |
| 8.8 to 9.4 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 6.5 | |
| 1.9 |
| Density, g/cm3 | 7.9 | |
| 7.1 to 7.5 |
| Embodied Carbon, kg CO2/kg material | 2.3 | |
| 1.5 |
| Embodied Energy, MJ/kg | 32 | |
| 21 |
| Embodied Water, L/kg | 62 | |
| 43 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 12 to 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 to 26 |
| Strength to Weight: Axial, points | 40 | |
| 17 to 35 |
| Strength to Weight: Bending, points | 31 | |
| 18 to 29 |
| Thermal Diffusivity, mm2/s | 11 | |
| 8.9 to 10 |
| Thermal Shock Resistance, points | 37 | |
| 17 to 35 |
Alloy Composition
| Carbon (C), % | 0.18 to 0.22 | |
| 3.0 to 3.5 |
| Chromium (Cr), % | 0 to 0.5 | |
| 0 |
| Cobalt (Co), % | 1.1 to 1.3 | |
| 0 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 92.1 to 94.2 | |
| 93.7 to 95.5 |
| Manganese (Mn), % | 0.35 to 0.72 | |
| 0 |
| Nickel (Ni), % | 3.9 to 4.3 | |
| 0 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.080 |
| Silicon (Si), % | 0.2 to 0.4 | |
| 1.5 to 2.8 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 |
| Vanadium (V), % | 0.15 to 0.25 | |
| 0 |