ACI-ASTM CF8M Steel vs. SAE-AISI 4340 Steel
Both ACI-ASTM CF8M steel and SAE-AISI 4340 steel are iron alloys. They have 70% of their average alloy composition in common. There are 30 material properties with values for both materials. Properties with values for just one material (3, in this case) are not shown.
For each property being compared, the top bar is ACI-ASTM CF8M steel and the bottom bar is SAE-AISI 4340 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 | |
| 210 to 360 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Elongation at Break, % | 50 | |
| 12 to 22 |
| Fatigue Strength, MPa | 280 | |
| 330 to 740 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 78 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 540 | |
| 690 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 290 | |
| 470 to 1150 |
Thermal Properties
| Latent Heat of Fusion, J/g | 300 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 1000 | |
| 430 |
| Melting Completion (Liquidus), °C | 1440 | |
| 1460 |
| Melting Onset (Solidus), °C | 1400 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 470 |
| Thermal Conductivity, W/m-K | 16 | |
| 44 |
| Thermal Expansion, µm/m-K | 16 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.0 | |
| 7.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.3 | |
| 8.6 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 19 | |
| 3.5 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.8 | |
| 1.7 |
| Embodied Energy, MJ/kg | 53 | |
| 22 |
| Embodied Water, L/kg | 160 | |
| 53 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 79 to 170 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 210 | |
| 590 to 3490 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 19 | |
| 24 to 45 |
| Strength to Weight: Bending, points | 19 | |
| 22 to 33 |
| Thermal Diffusivity, mm2/s | 4.3 | |
| 12 |
| Thermal Shock Resistance, points | 12 | |
| 20 to 38 |
Alloy Composition
| Carbon (C), % | 0 to 0.080 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 18 to 21 | |
| 0.7 to 0.9 |
| Iron (Fe), % | 60.3 to 71 | |
| 95.1 to 96.3 |
| Manganese (Mn), % | 0 to 1.5 | |
| 0.6 to 0.8 |
| Molybdenum (Mo), % | 2.0 to 3.0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 9.0 to 12 | |
| 1.7 to 2.0 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.035 |
| Silicon (Si), % | 0 to 2.0 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.040 |