ASTM A387 Grade 91 Class 2 vs. Chromium 33
ASTM A387 grade 91 class 2 belongs to the iron alloys classification, while chromium 33 belongs to the otherwise unclassified metals. They have 42% of their average alloy composition in common. There are 21 material properties with values for both materials. Properties with values for just one material (11, 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 chromium 33.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 20 | |
| 45 |
| Poisson's Ratio | 0.28 | |
| 0.27 |
| Shear Modulus, GPa | 75 | |
| 81 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 850 |
| Tensile Strength: Yield (Proof), MPa | 470 | |
| 430 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 320 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Expansion, µm/m-K | 13 | |
| 14 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.0 | |
| 36 |
| Density, g/cm3 | 7.8 | |
| 7.9 |
| Embodied Carbon, kg CO2/kg material | 2.6 | |
| 6.0 |
| Embodied Energy, MJ/kg | 37 | |
| 84 |
| Embodied Water, L/kg | 88 | |
| 250 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 320 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 580 | |
| 450 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 24 | |
| 30 |
| Strength to Weight: Bending, points | 22 | |
| 25 |
| Thermal Shock Resistance, points | 19 | |
| 21 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 0.080 to 0.12 | |
| 0 to 0.015 |
| Chromium (Cr), % | 8.0 to 9.5 | |
| 31 to 35 |
| Copper (Cu), % | 0 | |
| 0.3 to 1.2 |
| Iron (Fe), % | 87.3 to 90.3 | |
| 25.7 to 37.9 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0 to 2.0 |
| Molybdenum (Mo), % | 0.85 to 1.1 | |
| 0.5 to 2.0 |
| Nickel (Ni), % | 0 to 0.4 | |
| 30 to 33 |
| Niobium (Nb), % | 0.060 to 0.1 | |
| 0 |
| Nitrogen (N), % | 0.030 to 0.070 | |
| 0.35 to 0.6 |
| Phosphorus (P), % | 0 to 0.020 | |
| 0 to 0.020 |
| Silicon (Si), % | 0.2 to 0.5 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 to 0.010 |
| Titanium (Ti), % | 0 to 0.010 | |
| 0 |
| Vanadium (V), % | 0.18 to 0.25 | |
| 0 |
| Zirconium (Zr), % | 0 to 0.010 | |
| 0 |