ASTM A229 Class I vs. ASTM A229 Class II
Both ASTM A229 class I and ASTM A229 class II are variants of the same material. They share alloy composition and many physical properties, but develop different mechanical properties as a result of different processing.
For each property being compared, the top bar is ASTM A229 class I and the bottom bar is ASTM A229 class II.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 490 | |
| 550 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 14 | |
| 14 |
| Fatigue Strength, MPa | 710 | |
| 790 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 72 | |
| 72 |
| Shear Strength, MPa | 1020 | |
| 1140 |
| Tensile Strength: Ultimate (UTS), MPa | 1690 | |
| 1890 |
| Tensile Strength: Yield (Proof), MPa | 1100 | |
| 1230 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 400 | |
| 400 |
| Melting Completion (Liquidus), °C | 1450 | |
| 1450 |
| Melting Onset (Solidus), °C | 1410 | |
| 1410 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 50 | |
| 50 |
| Thermal Expansion, µm/m-K | 12 | |
| 12 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 7.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
| 8.3 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 1.8 | |
| 1.8 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 1.4 | |
| 1.4 |
| Embodied Energy, MJ/kg | 19 | |
| 19 |
| Embodied Water, L/kg | 46 | |
| 46 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 200 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 3260 | |
| 4080 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 60 | |
| 67 |
| Strength to Weight: Bending, points | 40 | |
| 43 |
| Thermal Diffusivity, mm2/s | 14 | |
| 14 |
| Thermal Shock Resistance, points | 54 | |
| 60 |
Alloy Composition
| Carbon (C), % | 0.55 to 0.85 | |
| 0.55 to 0.85 |
| Iron (Fe), % | 97.5 to 99 | |
| 97.5 to 99 |
| Manganese (Mn), % | 0.3 to 1.2 | |
| 0.3 to 1.2 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.050 | |
| 0 to 0.050 |