ASTM A231 Spring Steel vs. ASTM A387 Grade 12 Steel
Both ASTM A231 spring steel and ASTM A387 grade 12 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 (3, in this case) are not shown.
For each property being compared, the top bar is ASTM A231 spring steel and the bottom bar is ASTM A387 grade 12 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 540 | |
| 140 to 160 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 14 | |
| 25 |
| Fatigue Strength, MPa | 1000 | |
| 190 to 230 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Shear Strength, MPa | 1080 | |
| 300 to 330 |
| Tensile Strength: Ultimate (UTS), MPa | 1790 | |
| 470 to 520 |
| Tensile Strength: Yield (Proof), MPa | 1570 | |
| 260 to 310 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 430 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1470 |
| Melting Onset (Solidus), °C | 1410 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 52 | |
| 44 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 7.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 8.3 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.3 | |
| 2.8 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.0 | |
| 1.6 |
| Embodied Energy, MJ/kg | 28 | |
| 21 |
| Embodied Water, L/kg | 51 | |
| 51 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 98 to 110 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 64 | |
| 16 to 18 |
| Strength to Weight: Bending, points | 42 | |
| 17 to 18 |
| Thermal Diffusivity, mm2/s | 14 | |
| 12 |
| Thermal Shock Resistance, points | 53 | |
| 14 to 15 |
Alloy Composition
| Carbon (C), % | 0.48 to 0.53 | |
| 0.050 to 0.17 |
| Chromium (Cr), % | 0.8 to 1.1 | |
| 0.8 to 1.2 |
| Iron (Fe), % | 96.7 to 97.7 | |
| 97 to 98.2 |
| Manganese (Mn), % | 0.7 to 0.9 | |
| 0.4 to 0.65 |
| Molybdenum (Mo), % | 0 | |
| 0.45 to 0.6 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.025 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.15 to 0.4 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.025 |
| Vanadium (V), % | 0.15 to 0.3 | |
| 0 |