SAE-AISI M4 Steel vs. SAE-AISI A7 Steel
Both SAE-AISI M4 steel and SAE-AISI A7 steel are iron alloys. They have a moderately high 91% of their average alloy composition in common.
For each property being compared, the top bar is SAE-AISI M4 steel and the bottom bar is SAE-AISI A7 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 76 | |
| 72 |
| Tensile Strength: Ultimate (UTS), MPa | 770 to 2150 | |
| 800 to 2150 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 260 |
| Melting Completion (Liquidus), °C | 1610 | |
| 1470 |
| Melting Onset (Solidus), °C | 1560 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 440 | |
| 470 |
| Thermal Conductivity, W/m-K | 25 | |
| 37 |
| Thermal Expansion, µm/m-K | 12 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 25 | |
| 10 |
| Density, g/cm3 | 8.3 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 14 | |
| 13 |
| Embodied Energy, MJ/kg | 210 | |
| 200 |
| Embodied Water, L/kg | 110 | |
| 100 |
Common Calculations
| PREN (Pitting Resistance) | 30 | |
| 11 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 23 | |
| 25 |
| Strength to Weight: Axial, points | 26 to 72 | |
| 29 to 77 |
| Strength to Weight: Bending, points | 23 to 45 | |
| 25 to 48 |
| Thermal Diffusivity, mm2/s | 6.9 | |
| 10 |
| Thermal Shock Resistance, points | 24 to 68 | |
| 27 to 72 |
Alloy Composition
| Carbon (C), % | 1.3 to 1.4 | |
| 2.0 to 2.9 |
| Chromium (Cr), % | 3.8 to 4.8 | |
| 5.0 to 5.8 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 to 0.25 |
| Iron (Fe), % | 75.9 to 81.4 | |
| 81.4 to 87.7 |
| Manganese (Mn), % | 0.15 to 0.4 | |
| 0 to 0.8 |
| Molybdenum (Mo), % | 4.3 to 5.5 | |
| 0.9 to 1.4 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.2 to 0.45 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 5.3 to 6.5 | |
| 0.5 to 1.5 |
| Vanadium (V), % | 3.8 to 4.5 | |
| 3.9 to 5.2 |