Hardened SAE-AISI A8 vs. Hardened SAE-AISI M42
Both hardened SAE-AISI A8 and hardened SAE-AISI M42 are iron alloys. Both are furnished in the hardened (H) condition. They have 87% of their average alloy composition in common. There are 23 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown.
For each property being compared, the top bar is hardened SAE-AISI A8 and the bottom bar is hardened SAE-AISI M42.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Rockwell C Hardness | 59 | |
| 71 |
| Shear Modulus, GPa | 74 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 1920 | |
| 2310 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 270 |
| Melting Completion (Liquidus), °C | 1480 | |
| 1540 |
| Melting Onset (Solidus), °C | 1430 | |
| 1490 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 37 | |
| 20 |
| Thermal Expansion, µm/m-K | 12 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 8.5 | |
| 30 |
| Density, g/cm3 | 7.9 | |
| 8.2 |
| Embodied Carbon, kg CO2/kg material | 2.3 | |
| 7.4 |
| Embodied Energy, MJ/kg | 31 | |
| 100 |
| Embodied Water, L/kg | 73 | |
| 140 |
Common Calculations
| PREN (Pitting Resistance) | 12 | |
| 38 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 68 | |
| 79 |
| Strength to Weight: Bending, points | 44 | |
| 48 |
| Thermal Diffusivity, mm2/s | 9.9 | |
| 5.4 |
| Thermal Shock Resistance, points | 62 | |
| 71 |
Alloy Composition
| Carbon (C), % | 0.5 to 0.6 | |
| 1.1 to 1.2 |
| Chromium (Cr), % | 4.8 to 5.5 | |
| 3.5 to 4.3 |
| Cobalt (Co), % | 0 | |
| 7.8 to 8.8 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 to 0.25 |
| Iron (Fe), % | 88.5 to 91.9 | |
| 76.3 to 81 |
| Manganese (Mn), % | 0 to 0.5 | |
| 0.15 to 0.4 |
| Molybdenum (Mo), % | 1.2 to 1.7 | |
| 9.0 to 10 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.75 to 1.1 | |
| 0.15 to 0.65 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 1.0 to 1.5 | |
| 1.2 to 1.9 |
| Vanadium (V), % | 0 | |
| 1.0 to 1.4 |