SAE-AISI A7 Steel vs. ASTM A387 Grade 21 Steel
Both SAE-AISI A7 steel and ASTM A387 grade 21 steel are iron alloys. They have 89% of their average alloy composition in common. There are 22 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI A7 steel and the bottom bar is ASTM A387 grade 21 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 72 | |
| 74 |
| Tensile Strength: Ultimate (UTS), MPa | 800 to 2150 | |
| 500 to 590 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 260 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1470 |
| Melting Onset (Solidus), °C | 1430 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 37 | |
| 41 |
| Thermal Expansion, µm/m-K | 12 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 10 | |
| 4.1 |
| Density, g/cm3 | 7.7 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 13 | |
| 1.8 |
| Embodied Energy, MJ/kg | 200 | |
| 23 |
| Embodied Water, L/kg | 100 | |
| 62 |
Common Calculations
| PREN (Pitting Resistance) | 11 | |
| 6.4 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 29 to 77 | |
| 18 to 21 |
| Strength to Weight: Bending, points | 25 to 48 | |
| 18 to 20 |
| Thermal Diffusivity, mm2/s | 10 | |
| 11 |
| Thermal Shock Resistance, points | 27 to 72 | |
| 14 to 17 |
Alloy Composition
| Carbon (C), % | 2.0 to 2.9 | |
| 0.050 to 0.15 |
| Chromium (Cr), % | 5.0 to 5.8 | |
| 2.8 to 3.3 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 81.4 to 87.7 | |
| 94.4 to 96 |
| Manganese (Mn), % | 0 to 0.8 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0.9 to 1.4 | |
| 0.9 to 1.1 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.025 |
| Silicon (Si), % | 0 to 0.5 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.025 |
| Tungsten (W), % | 0.5 to 1.5 | |
| 0 |
| Vanadium (V), % | 3.9 to 5.2 | |
| 0 |