ASTM A372 Grade G Steel vs. ASTM A387 Grade 21 Steel
Both ASTM A372 grade G steel and ASTM A387 grade 21 steel are iron alloys. They have a very high 97% of their average alloy composition in common. There are 31 material properties with values for both materials. Properties with values for just one material (1, in this case) are not shown.
For each property being compared, the top bar is ASTM A372 grade G steel and the bottom bar is ASTM A387 grade 21 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 to 280 | |
| 150 to 180 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 20 to 22 | |
| 21 |
| Fatigue Strength, MPa | 310 to 380 | |
| 160 to 250 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 74 |
| Shear Strength, MPa | 410 to 570 | |
| 310 to 370 |
| Tensile Strength: Ultimate (UTS), MPa | 650 to 910 | |
| 500 to 590 |
| Tensile Strength: Yield (Proof), MPa | 430 to 550 | |
| 230 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 260 |
| Maximum Temperature: Mechanical, °C | 410 | |
| 480 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1470 |
| Melting Onset (Solidus), °C | 1420 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 46 | |
| 41 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 7.6 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
| 8.8 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.2 | |
| 4.1 |
| Density, g/cm3 | 7.8 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 1.8 |
| Embodied Energy, MJ/kg | 20 | |
| 23 |
| Embodied Water, L/kg | 49 | |
| 62 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 130 to 160 | |
| 84 to 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 500 to 810 | |
| 140 to 320 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 23 to 32 | |
| 18 to 21 |
| Strength to Weight: Bending, points | 21 to 27 | |
| 18 to 20 |
| Thermal Diffusivity, mm2/s | 13 | |
| 11 |
| Thermal Shock Resistance, points | 19 to 27 | |
| 14 to 17 |
Alloy Composition
| Carbon (C), % | 0.25 to 0.35 | |
| 0.050 to 0.15 |
| Chromium (Cr), % | 0.4 to 0.65 | |
| 2.8 to 3.3 |
| Iron (Fe), % | 97.4 to 98.4 | |
| 94.4 to 96 |
| Manganese (Mn), % | 0.7 to 1.0 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0.15 to 0.25 | |
| 0.9 to 1.1 |
| Phosphorus (P), % | 0 to 0.015 | |
| 0 to 0.025 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 to 0.025 |