Hardened SAE-AISI A8 vs. Hardened SAE-AISI P4
Both hardened SAE-AISI A8 and hardened SAE-AISI P4 are iron alloys. Both are furnished in the hardened (H) condition. They have a very high 96% of their average alloy composition in common.
For each property being compared, the top bar is hardened SAE-AISI A8 and the bottom bar is hardened SAE-AISI P4.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Rockwell C Hardness | 59 | |
| 61 |
| Shear Modulus, GPa | 74 | |
| 74 |
| Tensile Strength: Ultimate (UTS), MPa | 1920 | |
| 1980 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 260 |
| Melting Completion (Liquidus), °C | 1480 | |
| 1460 |
| Melting Onset (Solidus), °C | 1430 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 37 | |
| 41 |
| Thermal Expansion, µm/m-K | 12 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 8.3 | |
| 8.1 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 9.5 | |
| 9.3 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 8.5 | |
| 4.4 |
| Density, g/cm3 | 7.9 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.3 | |
| 1.8 |
| Embodied Energy, MJ/kg | 31 | |
| 23 |
| Embodied Water, L/kg | 73 | |
| 68 |
Common Calculations
| PREN (Pitting Resistance) | 12 | |
| 7.0 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 68 | |
| 70 |
| Strength to Weight: Bending, points | 44 | |
| 45 |
| Thermal Diffusivity, mm2/s | 9.9 | |
| 11 |
| Thermal Shock Resistance, points | 62 | |
| 64 |
Alloy Composition
| Carbon (C), % | 0.5 to 0.6 | |
| 0 to 0.12 |
| Chromium (Cr), % | 4.8 to 5.5 | |
| 4.0 to 5.3 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 to 0.25 |
| Iron (Fe), % | 88.5 to 91.9 | |
| 92.3 to 95.3 |
| Manganese (Mn), % | 0 to 0.5 | |
| 0.2 to 0.6 |
| Molybdenum (Mo), % | 1.2 to 1.7 | |
| 0.4 to 1.0 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.75 to 1.1 | |
| 0.1 to 0.4 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 1.0 to 1.5 | |
| 0 |