ASTM A356 Grade 8 vs. ASTM A356 Grade 9
Both ASTM A356 grade 8 and ASTM A356 grade 9 are iron alloys. Both are furnished in the heat treated (HT) condition. Their average alloy composition is basically identical.
For each property being compared, the top bar is ASTM A356 grade 8 and the bottom bar is ASTM A356 grade 9.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 190 | |
| 200 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 21 | |
| 17 |
| Fatigue Strength, MPa | 270 | |
| 310 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 50 | |
| 50 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 630 | |
| 670 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 460 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 260 |
| Maximum Temperature: Mechanical, °C | 440 | |
| 440 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1470 |
| Melting Onset (Solidus), °C | 1430 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 38 | |
| 41 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.5 | |
| 7.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.6 | |
| 8.6 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.5 | |
| 3.6 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.0 | |
| 2.4 |
| Embodied Energy, MJ/kg | 26 | |
| 33 |
| Embodied Water, L/kg | 55 | |
| 56 |
Common Calculations
| PREN (Pitting Resistance) | 4.7 | |
| 4.7 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 | |
| 100 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 | |
| 570 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 22 | |
| 24 |
| Strength to Weight: Bending, points | 21 | |
| 22 |
| Thermal Diffusivity, mm2/s | 10 | |
| 11 |
| Thermal Shock Resistance, points | 18 | |
| 19 |
Alloy Composition
| Carbon (C), % | 0 to 0.2 | |
| 0 to 0.2 |
| Chromium (Cr), % | 1.0 to 1.5 | |
| 1.0 to 1.5 |
| Iron (Fe), % | 95.4 to 97.4 | |
| 95.2 to 97.2 |
| Manganese (Mn), % | 0.5 to 0.9 | |
| 0.5 to 0.9 |
| Molybdenum (Mo), % | 0.9 to 1.2 | |
| 0.9 to 1.2 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.035 |
| Silicon (Si), % | 0.2 to 0.6 | |
| 0.2 to 0.6 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Vanadium (V), % | 0.050 to 0.15 | |
| 0.2 to 0.35 |