Grade 20 Cast Iron vs. ASTM B780 Alloy
Grade 20 cast iron belongs to the iron alloys classification, while ASTM B780 alloy belongs to the otherwise unclassified metals. There are 17 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 grade 20 cast iron and the bottom bar is ASTM B780 alloy.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 180 | |
| 83 |
| Elongation at Break, % | 9.6 | |
| 1.1 to 9.1 |
| Poisson's Ratio | 0.29 | |
| 0.36 |
| Shear Modulus, GPa | 69 | |
| 30 |
| Shear Strength, MPa | 180 | |
| 200 to 340 |
| Tensile Strength: Ultimate (UTS), MPa | 160 | |
| 330 to 590 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 140 |
| Specific Heat Capacity, J/kg-K | 490 | |
| 270 |
| Thermal Expansion, µm/m-K | 11 | |
| 18 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.4 | |
| 70 to 76 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.9 | |
| 62 to 68 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.5 | |
| 10 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 4.5 |
| Stiffness to Weight: Bending, points | 25 | |
| 14 |
| Strength to Weight: Axial, points | 5.8 | |
| 9.1 to 16 |
| Strength to Weight: Bending, points | 8.7 | |
| 11 to 15 |
| Thermal Shock Resistance, points | 6.0 | |
| 16 to 29 |
Alloy Composition
| Cadmium (Cd), % | 0 | |
| 0 to 0.050 |
| Carbon (C), % | 3.1 to 3.4 | |
| 0 |
| Copper (Cu), % | 0 | |
| 23.5 to 25.7 |
| Iron (Fe), % | 92.1 to 93.9 | |
| 0 to 0.050 |
| Lead (Pb), % | 0 | |
| 0 to 0.030 |
| Manganese (Mn), % | 0.5 to 0.7 | |
| 0 |
| Nickel (Ni), % | 0 | |
| 0.35 to 0.65 |
| Phosphorus (P), % | 0 to 0.9 | |
| 0 |
| Silicon (Si), % | 2.5 to 2.8 | |
| 0 |
| Silver (Ag), % | 0 | |
| 74 to 76 |
| Sulfur (S), % | 0 to 0.15 | |
| 0 |
| Zinc (Zn), % | 0 | |
| 0 to 0.060 |