ASTM A387 Grade 21 Steel vs. ASTM B685 Alloy
ASTM A387 grade 21 steel belongs to the iron alloys classification, while ASTM B685 alloy belongs to the otherwise unclassified metals. There are 17 material properties with values for both materials. Properties with values for just one material (15, in this case) are not shown.
For each property being compared, the top bar is ASTM A387 grade 21 steel and the bottom bar is ASTM B685 alloy.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 120 |
| Poisson's Ratio | 0.29 | |
| 0.37 |
| Shear Modulus, GPa | 74 | |
| 43 |
| Tensile Strength: Ultimate (UTS), MPa | 500 to 590 | |
| 660 to 1060 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 180 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1230 |
| Melting Onset (Solidus), °C | 1430 | |
| 1200 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 300 |
| Thermal Expansion, µm/m-K | 13 | |
| 14 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.6 | |
| 5.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.8 | |
| 4.1 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.9 | |
| 11 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 6.1 |
| Stiffness to Weight: Bending, points | 24 | |
| 15 |
| Strength to Weight: Axial, points | 18 to 21 | |
| 17 to 27 |
| Strength to Weight: Bending, points | 18 to 20 | |
| 16 to 21 |
| Thermal Shock Resistance, points | 14 to 17 | |
| 28 to 46 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0 to 0.0050 |
| Cadmium (Cd), % | 0 | |
| 0 to 0.050 |
| Carbon (C), % | 0.050 to 0.15 | |
| 0 |
| Chromium (Cr), % | 2.8 to 3.3 | |
| 0 |
| Copper (Cu), % | 0 | |
| 39.5 to 40.5 |
| Iron (Fe), % | 94.4 to 96 | |
| 0 to 0.050 |
| Lead (Pb), % | 0 | |
| 0 to 0.030 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0 |
| Molybdenum (Mo), % | 0.9 to 1.1 | |
| 0 |
| Palladium (Pd), % | 0 | |
| 59 to 60.5 |
| Phosphorus (P), % | 0 to 0.025 | |
| 0 |
| Silicon (Si), % | 0 to 0.5 | |
| 0 |
| Silver (Ag), % | 0 | |
| 0 to 0.1 |
| Sulfur (S), % | 0 to 0.025 | |
| 0 |
| Zinc (Zn), % | 0 | |
| 0 to 0.060 |
| Residuals, % | 0 | |
| 0 to 0.2 |