SAE-AISI 4340 Steel vs. AISI 440A Stainless Steel
Both SAE-AISI 4340 steel and AISI 440A stainless steel are iron alloys. They have 83% of their average alloy composition in common. There are 29 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4340 steel and the bottom bar is AISI 440A stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 12 to 22 | |
| 5.0 to 20 |
| Fatigue Strength, MPa | 330 to 740 | |
| 270 to 790 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 73 | |
| 77 |
| Shear Strength, MPa | 430 to 770 | |
| 450 to 1040 |
| Tensile Strength: Ultimate (UTS), MPa | 690 to 1280 | |
| 730 to 1790 |
| Tensile Strength: Yield (Proof), MPa | 470 to 1150 | |
| 420 to 1650 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 280 |
| Maximum Temperature: Mechanical, °C | 430 | |
| 760 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1480 |
| Melting Onset (Solidus), °C | 1420 | |
| 1370 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 44 | |
| 23 |
| Thermal Expansion, µm/m-K | 13 | |
| 10 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.5 | |
| 2.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.6 | |
| 2.9 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.5 | |
| 9.0 |
| Density, g/cm3 | 7.8 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 1.7 | |
| 2.2 |
| Embodied Energy, MJ/kg | 22 | |
| 31 |
| Embodied Water, L/kg | 53 | |
| 120 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 79 to 170 | |
| 87 to 120 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 24 to 45 | |
| 26 to 65 |
| Strength to Weight: Bending, points | 22 to 33 | |
| 23 to 43 |
| Thermal Diffusivity, mm2/s | 12 | |
| 6.2 |
| Thermal Shock Resistance, points | 20 to 38 | |
| 26 to 65 |
Alloy Composition
| Carbon (C), % | 0.38 to 0.43 | |
| 0.6 to 0.75 |
| Chromium (Cr), % | 0.7 to 0.9 | |
| 16 to 18 |
| Iron (Fe), % | 95.1 to 96.3 | |
| 78.4 to 83.4 |
| Manganese (Mn), % | 0.6 to 0.8 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 0 to 0.75 |
| Nickel (Ni), % | 1.7 to 2.0 | |
| 0 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.015 |