ASTM A369 Grade FP91 vs. ASTM A387 Grade 9 Steel
Both ASTM A369 grade FP91 and ASTM A387 grade 9 steel are iron alloys. Their average alloy composition is basically identical.
For each property being compared, the top bar is ASTM A369 grade FP91 and the bottom bar is ASTM A387 grade 9 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 | |
| 150 to 180 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 19 | |
| 20 to 21 |
| Fatigue Strength, MPa | 320 | |
| 160 to 240 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 75 | |
| 75 |
| Shear Strength, MPa | 410 | |
| 310 to 380 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 500 to 600 |
| Tensile Strength: Yield (Proof), MPa | 460 | |
| 230 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 270 |
| Maximum Temperature: Mechanical, °C | 600 | |
| 600 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1460 |
| Melting Onset (Solidus), °C | 1420 | |
| 1410 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 470 |
| Thermal Conductivity, W/m-K | 26 | |
| 26 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 8.9 | |
| 9.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 10 | |
| 10 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.0 | |
| 6.5 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.6 | |
| 2.1 |
| Embodied Energy, MJ/kg | 37 | |
| 28 |
| Embodied Water, L/kg | 88 | |
| 87 |
Common Calculations
| PREN (Pitting Resistance) | 13 | |
| 12 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 | |
| 83 to 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 560 | |
| 140 to 310 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 24 | |
| 18 to 21 |
| Strength to Weight: Bending, points | 22 | |
| 18 to 20 |
| Thermal Diffusivity, mm2/s | 6.9 | |
| 6.9 |
| Thermal Shock Resistance, points | 18 | |
| 14 to 17 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 0.080 to 0.12 | |
| 0 to 0.15 |
| Chromium (Cr), % | 8.0 to 9.5 | |
| 8.0 to 10 |
| Iron (Fe), % | 87.3 to 90.3 | |
| 87.1 to 90.8 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0.85 to 1.1 | |
| 0.9 to 1.1 |
| Nickel (Ni), % | 0 to 0.4 | |
| 0 |
| Niobium (Nb), % | 0.060 to 0.1 | |
| 0 |
| Nitrogen (N), % | 0.030 to 0.070 | |
| 0 |
| Phosphorus (P), % | 0 to 0.025 | |
| 0 to 0.025 |
| Silicon (Si), % | 0.2 to 0.5 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.025 | |
| 0 to 0.025 |
| Titanium (Ti), % | 0 to 0.010 | |
| 0 |
| Vanadium (V), % | 0.18 to 0.25 | |
| 0 to 0.040 |
| Zirconium (Zr), % | 0 to 0.010 | |
| 0 |