ASTM A387 Grade 91 Class 2 vs. AISI 304 Stainless Steel
Both ASTM A387 grade 91 class 2 and AISI 304 stainless steel are iron alloys. They have 80% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown.
For each property being compared, the top bar is ASTM A387 grade 91 class 2 and the bottom bar is AISI 304 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 | |
| 170 to 360 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 20 | |
| 8.0 to 43 |
| Fatigue Strength, MPa | 330 | |
| 210 to 440 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 75 | |
| 77 |
| Shear Strength, MPa | 420 | |
| 400 to 690 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 580 to 1180 |
| Tensile Strength: Yield (Proof), MPa | 470 | |
| 230 to 860 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 290 |
| Maximum Temperature: Mechanical, °C | 600 | |
| 710 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1450 |
| Melting Onset (Solidus), °C | 1420 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 26 | |
| 16 |
| Thermal Expansion, µm/m-K | 13 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 8.9 | |
| 2.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 10 | |
| 2.7 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.0 | |
| 15 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 2.6 | |
| 3.0 |
| Embodied Energy, MJ/kg | 37 | |
| 43 |
| Embodied Water, L/kg | 88 | |
| 150 |
Common Calculations
| PREN (Pitting Resistance) | 13 | |
| 20 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 86 to 250 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 580 | |
| 140 to 1870 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 24 | |
| 21 to 42 |
| Strength to Weight: Bending, points | 22 | |
| 20 to 32 |
| Thermal Diffusivity, mm2/s | 6.9 | |
| 4.2 |
| Thermal Shock Resistance, points | 19 | |
| 12 to 25 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 0.080 to 0.12 | |
| 0 to 0.080 |
| Chromium (Cr), % | 8.0 to 9.5 | |
| 18 to 20 |
| Iron (Fe), % | 87.3 to 90.3 | |
| 66.5 to 74 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0 to 2.0 |
| Molybdenum (Mo), % | 0.85 to 1.1 | |
| 0 |
| Nickel (Ni), % | 0 to 0.4 | |
| 8.0 to 10.5 |
| Niobium (Nb), % | 0.060 to 0.1 | |
| 0 |
| Nitrogen (N), % | 0.030 to 0.070 | |
| 0 to 0.1 |
| Phosphorus (P), % | 0 to 0.020 | |
| 0 to 0.045 |
| Silicon (Si), % | 0.2 to 0.5 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 to 0.010 | |
| 0 |
| Vanadium (V), % | 0.18 to 0.25 | |
| 0 |
| Zirconium (Zr), % | 0 to 0.010 | |
| 0 |