SAE-AISI 1039 Steel vs. SAE-AISI 1078 Steel
Both SAE-AISI 1039 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 SAE-AISI 1039 steel and the bottom bar is SAE-AISI 1078 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 180 to 200 | |
| 220 to 230 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 14 to 18 | |
| 11 to 14 |
| Fatigue Strength, MPa | 230 to 370 | |
| 270 to 350 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Reduction in Area, % | 40 to 45 | |
| 34 to 45 |
| Shear Modulus, GPa | 73 | |
| 72 |
| Shear Strength, MPa | 380 to 420 | |
| 440 to 470 |
| Tensile Strength: Ultimate (UTS), MPa | 610 to 690 | |
| 730 to 780 |
| Tensile Strength: Yield (Proof), MPa | 340 to 580 | |
| 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 | 7.0 | |
| 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 | 88 to 94 | |
| 77 to 90 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 310 to 890 | |
| 490 to 860 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 22 to 24 | |
| 26 to 28 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 23 to 24 |
| Thermal Diffusivity, mm2/s | 14 | |
| 13 |
| Thermal Shock Resistance, points | 19 to 22 | |
| 25 to 26 |
Alloy Composition
| Carbon (C), % | 0.37 to 0.44 | |
| 0.72 to 0.85 |
| Iron (Fe), % | 98.5 to 98.9 | |
| 98.5 to 99 |
| Manganese (Mn), % | 0.7 to 1.0 | |
| 0.3 to 0.6 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Sulfur (S), % | 0 to 0.050 | |
| 0 to 0.050 |