ASTM A321 Carbon Steel vs. SAE-AISI 1078 Steel
Both ASTM A321 carbon steel and SAE-AISI 1078 steel are iron alloys. Their average alloy composition is basically identical.
For each property being compared, the top bar is ASTM A321 carbon steel and the bottom bar is SAE-AISI 1078 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 190 | |
| 220 to 230 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 21 | |
| 11 to 14 |
| Fatigue Strength, MPa | 270 | |
| 270 to 350 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 39 | |
| 34 to 45 |
| Shear Modulus, GPa | 73 | |
| 72 |
| Shear Strength, MPa | 420 | |
| 440 to 470 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 730 to 780 |
| Tensile Strength: Yield (Proof), MPa | 390 | |
| 430 to 570 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 400 | |
| 400 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1460 |
| Melting Onset (Solidus), °C | 1420 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 51 | |
| 49 |
| Thermal Expansion, µm/m-K | 12 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.1 | |
| 7.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.1 | |
| 8.1 |
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 | 18 | |
| 18 |
| Embodied Water, L/kg | 46 | |
| 45 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 77 to 90 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 400 | |
| 490 to 860 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 24 | |
| 26 to 28 |
| Strength to Weight: Bending, points | 22 | |
| 23 to 24 |
| Thermal Diffusivity, mm2/s | 14 | |
| 13 |
| Thermal Shock Resistance, points | 21 | |
| 25 to 26 |
Alloy Composition
| Carbon (C), % | 0 to 0.55 | |
| 0.72 to 0.85 |
| Iron (Fe), % | 98.1 to 99.25 | |
| 98.5 to 99 |
| Manganese (Mn), % | 0.6 to 0.9 | |
| 0.3 to 0.6 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 |
| Sulfur (S), % | 0 to 0.050 | |
| 0 to 0.050 |