ASTM A369 Grade FPA vs. SAE-AISI 4320 Steel
Both ASTM A369 grade FPA and SAE-AISI 4320 steel are iron alloys. They have a very high 97% of their average alloy composition in common.
For each property being compared, the top bar is ASTM A369 grade FPA and the bottom bar is SAE-AISI 4320 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 110 | |
| 160 to 240 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 27 | |
| 21 to 29 |
| Fatigue Strength, MPa | 180 | |
| 320 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Shear Strength, MPa | 240 | |
| 370 to 500 |
| Tensile Strength: Ultimate (UTS), MPa | 380 | |
| 570 to 790 |
| Tensile Strength: Yield (Proof), MPa | 240 | |
| 430 to 460 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 400 | |
| 420 |
| 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 | 52 | |
| 46 |
| Thermal Expansion, µm/m-K | 12 | |
| 11 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.1 | |
| 7.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.1 | |
| 8.5 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 1.8 | |
| 3.4 |
| Density, g/cm3 | 7.8 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 1.4 | |
| 1.7 |
| Embodied Energy, MJ/kg | 18 | |
| 22 |
| Embodied Water, L/kg | 46 | |
| 52 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 89 | |
| 140 to 150 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 150 | |
| 480 to 560 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 13 | |
| 20 to 28 |
| Strength to Weight: Bending, points | 15 | |
| 19 to 24 |
| Thermal Diffusivity, mm2/s | 14 | |
| 13 |
| Thermal Shock Resistance, points | 12 | |
| 19 to 27 |
Alloy Composition
| Carbon (C), % | 0 to 0.25 | |
| 0.17 to 0.22 |
| Chromium (Cr), % | 0 | |
| 0.4 to 0.6 |
| Iron (Fe), % | 98.3 to 99.63 | |
| 95.8 to 97 |
| Manganese (Mn), % | 0.27 to 0.93 | |
| 0.45 to 0.65 |
| Molybdenum (Mo), % | 0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 0 | |
| 1.7 to 2.0 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.035 |
| Silicon (Si), % | 0.1 to 0.5 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.035 | |
| 0 to 0.040 |