Hardened AISI 440A vs. Hardened AISI 431
Both hardened AISI 440A and hardened AISI 431 are iron alloys. Both are furnished in the hardened (H) condition. They have a very high 98% of their average alloy composition in common. There are 31 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 hardened AISI 440A and the bottom bar is hardened AISI 431.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 200 |
| Elongation at Break, % | 5.0 | |
| 15 |
| Fatigue Strength, MPa | 790 | |
| 610 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 77 | |
| 77 |
| Shear Strength, MPa | 1040 | |
| 840 |
| Tensile Strength: Ultimate (UTS), MPa | 1790 | |
| 1380 |
| Tensile Strength: Yield (Proof), MPa | 1650 | |
| 1040 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 280 |
| Maximum Temperature: Corrosion, °C | 400 | |
| 400 |
| Maximum Temperature: Mechanical, °C | 760 | |
| 850 |
| Melting Completion (Liquidus), °C | 1480 | |
| 1510 |
| Melting Onset (Solidus), °C | 1370 | |
| 1450 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 480 |
| Thermal Conductivity, W/m-K | 23 | |
| 26 |
| Thermal Expansion, µm/m-K | 10 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.5 | |
| 2.6 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.9 | |
| 3.0 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 9.0 | |
| 9.0 |
| Density, g/cm3 | 7.7 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 2.2 | |
| 2.2 |
| Embodied Energy, MJ/kg | 31 | |
| 31 |
| Embodied Water, L/kg | 120 | |
| 120 |
Common Calculations
| PREN (Pitting Resistance) | 18 | |
| 16 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 87 | |
| 180 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 65 | |
| 50 |
| Strength to Weight: Bending, points | 43 | |
| 36 |
| Thermal Diffusivity, mm2/s | 6.2 | |
| 7.0 |
| Thermal Shock Resistance, points | 65 | |
| 43 |
Alloy Composition
| Carbon (C), % | 0.6 to 0.75 | |
| 0 to 0.2 |
| Chromium (Cr), % | 16 to 18 | |
| 15 to 17 |
| Iron (Fe), % | 78.4 to 83.4 | |
| 78.2 to 83.8 |
| Manganese (Mn), % | 0 to 1.0 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0 to 0.75 | |
| 0 |
| Nickel (Ni), % | 0 | |
| 1.3 to 2.5 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.015 | |
| 0 to 0.030 |