SAE-AISI 8740 Steel vs. SAE-AISI M42 Steel
Both SAE-AISI 8740 steel and SAE-AISI M42 steel are iron alloys. They have 81% of their average alloy composition in common. There are 21 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 8740 steel and the bottom bar is SAE-AISI M42 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
| 810 to 2310 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 270 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1540 |
| Melting Onset (Solidus), °C | 1420 | |
| 1490 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 450 |
| Thermal Conductivity, W/m-K | 39 | |
| 20 |
| Thermal Expansion, µm/m-K | 13 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.6 | |
| 30 |
| Density, g/cm3 | 7.8 | |
| 8.2 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 7.4 |
| Embodied Energy, MJ/kg | 20 | |
| 100 |
| Embodied Water, L/kg | 50 | |
| 140 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 20 to 24 | |
| 28 to 79 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 24 to 48 |
| Thermal Diffusivity, mm2/s | 10 | |
| 5.4 |
| Thermal Shock Resistance, points | 17 to 20 | |
| 25 to 71 |
Alloy Composition
| Carbon (C), % | 0.38 to 0.43 | |
| 1.1 to 1.2 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 3.5 to 4.3 |
| Cobalt (Co), % | 0 | |
| 7.8 to 8.8 |
| Copper (Cu), % | 0 | |
| 0 to 0.25 |
| Iron (Fe), % | 96.5 to 97.7 | |
| 76.3 to 81 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0.15 to 0.4 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 9.0 to 10 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.15 to 0.65 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |
| Tungsten (W), % | 0 | |
| 1.2 to 1.9 |
| Vanadium (V), % | 0 | |
| 1.0 to 1.4 |