ASTM A387 Grade 12 Class 2 vs. ASTM A387 Grade 22 Class 2
Both ASTM A387 grade 12 class 2 and ASTM A387 grade 22 class 2 are iron alloys. Both are furnished in the normalized and tempered condition. They have a very high 98% of their average alloy composition in common.
For each property being compared, the top bar is ASTM A387 grade 12 class 2 and the bottom bar is ASTM A387 grade 22 class 2.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 160 | |
| 180 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 25 | |
| 21 |
| Fatigue Strength, MPa | 230 | |
| 240 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 74 |
| Shear Strength, MPa | 330 | |
| 380 |
| Tensile Strength: Ultimate (UTS), MPa | 520 | |
| 600 |
| Tensile Strength: Yield (Proof), MPa | 310 | |
| 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 260 |
| Maximum Temperature: Mechanical, °C | 430 | |
| 460 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1470 |
| Melting Onset (Solidus), °C | 1420 | |
| 1430 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 44 | |
| 40 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 7.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
| 8.6 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.8 | |
| 3.8 |
| Density, g/cm3 | 7.8 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 1.6 | |
| 1.7 |
| Embodied Energy, MJ/kg | 21 | |
| 23 |
| Embodied Water, L/kg | 51 | |
| 58 |
Common Calculations
| PREN (Pitting Resistance) | 2.7 | |
| 5.6 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 | |
| 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 250 | |
| 320 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 18 | |
| 21 |
| Strength to Weight: Bending, points | 18 | |
| 20 |
| Thermal Diffusivity, mm2/s | 12 | |
| 11 |
| Thermal Shock Resistance, points | 15 | |
| 17 |
Alloy Composition
| Carbon (C), % | 0.050 to 0.17 | |
| 0.050 to 0.15 |
| Chromium (Cr), % | 0.8 to 1.2 | |
| 2.0 to 2.5 |
| Iron (Fe), % | 97 to 98.2 | |
| 95.1 to 96.8 |
| Manganese (Mn), % | 0.4 to 0.65 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0.45 to 0.6 | |
| 0.9 to 1.1 |
| Phosphorus (P), % | 0 to 0.025 | |
| 0 to 0.025 |
| Silicon (Si), % | 0.15 to 0.4 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.025 | |
| 0 to 0.025 |