ASTM A231 Spring Steel vs. SAE-AISI 4140 Steel
Both ASTM A231 spring steel and SAE-AISI 4140 steel are iron alloys. Their average alloy composition is basically identical. 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 ASTM A231 spring steel and the bottom bar is SAE-AISI 4140 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 540 | |
| 200 to 310 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 14 | |
| 11 to 26 |
| Fatigue Strength, MPa | 1000 | |
| 360 to 650 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Shear Strength, MPa | 1080 | |
| 410 to 660 |
| Tensile Strength: Ultimate (UTS), MPa | 1790 | |
| 690 to 1080 |
| Tensile Strength: Yield (Proof), MPa | 1570 | |
| 590 to 990 |
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 | 1410 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 52 | |
| 43 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 7.3 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 8.4 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.3 | |
| 2.4 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.0 | |
| 1.5 |
| Embodied Energy, MJ/kg | 28 | |
| 20 |
| Embodied Water, L/kg | 51 | |
| 51 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 74 to 180 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 64 | |
| 25 to 38 |
| Strength to Weight: Bending, points | 42 | |
| 22 to 30 |
| Thermal Diffusivity, mm2/s | 14 | |
| 12 |
| Thermal Shock Resistance, points | 53 | |
| 20 to 32 |
Alloy Composition
| Carbon (C), % | 0.48 to 0.53 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 0.8 to 1.1 | |
| 0.8 to 1.1 |
| Iron (Fe), % | 96.7 to 97.7 | |
| 96.8 to 97.8 |
| Manganese (Mn), % | 0.7 to 0.9 | |
| 0.75 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 0.15 to 0.25 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.035 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.040 |
| Vanadium (V), % | 0.15 to 0.3 | |
| 0 |