SAE-AISI 4320 Steel vs. ASTM A231 Spring Steel
Both SAE-AISI 4320 steel and ASTM A231 spring steel are iron alloys. They have a very high 98% of their average alloy composition in common. There are 30 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4320 steel and the bottom bar is ASTM A231 spring steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 160 to 240 | |
| 540 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 21 to 29 | |
| 14 |
| Fatigue Strength, MPa | 320 | |
| 1000 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Shear Strength, MPa | 370 to 500 | |
| 1080 |
| Tensile Strength: Ultimate (UTS), MPa | 570 to 790 | |
| 1790 |
| Tensile Strength: Yield (Proof), MPa | 430 to 460 | |
| 1570 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 420 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1460 |
| Melting Onset (Solidus), °C | 1420 | |
| 1410 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 46 | |
| 52 |
| Thermal Expansion, µm/m-K | 11 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.4 | |
| 7.3 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.5 | |
| 8.4 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.4 | |
| 2.3 |
| Density, g/cm3 | 7.9 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 1.7 | |
| 2.0 |
| Embodied Energy, MJ/kg | 22 | |
| 28 |
| Embodied Water, L/kg | 52 | |
| 51 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 150 | |
| 230 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 20 to 28 | |
| 64 |
| Strength to Weight: Bending, points | 19 to 24 | |
| 42 |
| Thermal Diffusivity, mm2/s | 13 | |
| 14 |
| Thermal Shock Resistance, points | 19 to 27 | |
| 53 |
Alloy Composition
| Carbon (C), % | 0.17 to 0.22 | |
| 0.48 to 0.53 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 0.8 to 1.1 |
| Iron (Fe), % | 95.8 to 97 | |
| 96.7 to 97.7 |
| Manganese (Mn), % | 0.45 to 0.65 | |
| 0.7 to 0.9 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 0 |
| 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 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.040 |
| Vanadium (V), % | 0 | |
| 0.15 to 0.3 |