Austempered Cast Iron vs. ASTM A387 Grade 21 Steel
Both austempered cast iron and ASTM A387 grade 21 steel are iron alloys. They have a moderately high 93% of their average alloy composition in common. There are 26 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.
For each property being compared, the top bar is austempered cast iron and the bottom bar is ASTM A387 grade 21 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 270 to 490 | |
| 150 to 180 |
| Elastic (Young's, Tensile) Modulus, GPa | 180 | |
| 190 |
| Elongation at Break, % | 1.1 to 13 | |
| 21 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 62 to 69 | |
| 74 |
| Tensile Strength: Ultimate (UTS), MPa | 860 to 1800 | |
| 500 to 590 |
| Tensile Strength: Yield (Proof), MPa | 560 to 1460 | |
| 230 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 260 |
| Melting Completion (Liquidus), °C | 1380 | |
| 1470 |
| Melting Onset (Solidus), °C | 1340 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 490 | |
| 470 |
| Thermal Conductivity, W/m-K | 42 | |
| 41 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.9 | |
| 4.1 |
| Density, g/cm3 | 7.5 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 1.8 | |
| 1.8 |
| Embodied Energy, MJ/kg | 25 | |
| 23 |
| Embodied Water, L/kg | 48 | |
| 62 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 19 to 95 | |
| 84 to 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 880 to 3970 | |
| 140 to 320 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 32 to 66 | |
| 18 to 21 |
| Strength to Weight: Bending, points | 27 to 44 | |
| 18 to 20 |
| Thermal Diffusivity, mm2/s | 11 | |
| 11 |
| Thermal Shock Resistance, points | 25 to 53 | |
| 14 to 17 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.050 | |
| 0 |
| Arsenic (As), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 3.4 to 3.8 | |
| 0.050 to 0.15 |
| Chromium (Cr), % | 0 to 0.1 | |
| 2.8 to 3.3 |
| Copper (Cu), % | 0 to 0.8 | |
| 0 |
| Iron (Fe), % | 89.6 to 94 | |
| 94.4 to 96 |
| Magnesium (Mg), % | 0 to 0.040 | |
| 0 |
| Manganese (Mn), % | 0.3 to 0.4 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0 to 0.3 | |
| 0.9 to 1.1 |
| Nickel (Ni), % | 0 to 2.0 | |
| 0 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.025 |
| Selenium (Se), % | 0 to 0.030 | |
| 0 |
| Silicon (Si), % | 2.3 to 2.7 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.020 | |
| 0 to 0.025 |
| Tin (Sn), % | 0 to 0.020 | |
| 0 |
| Vanadium (V), % | 0 to 0.1 | |
| 0 |