S21904 Stainless Steel vs. ASTM A387 Grade 91 Class 2
Both S21904 stainless steel and ASTM A387 grade 91 class 2 are iron alloys. They have 73% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (1, in this case) are not shown.
For each property being compared, the top bar is S21904 stainless steel and the bottom bar is ASTM A387 grade 91 class 2.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 210 to 300 | |
| 200 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Elongation at Break, % | 17 to 51 | |
| 20 |
| Fatigue Strength, MPa | 380 to 550 | |
| 330 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 78 | |
| 75 |
| Shear Strength, MPa | 510 to 620 | |
| 420 |
| Tensile Strength: Ultimate (UTS), MPa | 700 to 1000 | |
| 670 |
| Tensile Strength: Yield (Proof), MPa | 390 to 910 | |
| 470 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 270 |
| Maximum Temperature: Mechanical, °C | 980 | |
| 600 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1460 |
| Melting Onset (Solidus), °C | 1350 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 470 |
| Thermal Conductivity, W/m-K | 14 | |
| 26 |
| Thermal Expansion, µm/m-K | 17 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.5 | |
| 8.9 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.9 | |
| 10 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 15 | |
| 7.0 |
| Density, g/cm3 | 7.7 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.0 | |
| 2.6 |
| Embodied Energy, MJ/kg | 43 | |
| 37 |
| Embodied Water, L/kg | 160 | |
| 88 |
Common Calculations
| PREN (Pitting Resistance) | 25 | |
| 13 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 160 to 310 | |
| 120 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 380 to 2070 | |
| 580 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 25 to 36 | |
| 24 |
| Strength to Weight: Bending, points | 23 to 29 | |
| 22 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 6.9 |
| Thermal Shock Resistance, points | 15 to 21 | |
| 19 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 0 to 0.020 |
| Carbon (C), % | 0 to 0.040 | |
| 0.080 to 0.12 |
| Chromium (Cr), % | 19 to 21.5 | |
| 8.0 to 9.5 |
| Iron (Fe), % | 59.5 to 67.4 | |
| 87.3 to 90.3 |
| Manganese (Mn), % | 8.0 to 10 | |
| 0.3 to 0.6 |
| Molybdenum (Mo), % | 0 | |
| 0.85 to 1.1 |
| Nickel (Ni), % | 5.5 to 7.5 | |
| 0 to 0.4 |
| Niobium (Nb), % | 0 | |
| 0.060 to 0.1 |
| Nitrogen (N), % | 0.15 to 0.4 | |
| 0.030 to 0.070 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.020 |
| Silicon (Si), % | 0 to 1.0 | |
| 0.2 to 0.5 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.010 |
| Titanium (Ti), % | 0 | |
| 0 to 0.010 |
| Vanadium (V), % | 0 | |
| 0.18 to 0.25 |
| Zirconium (Zr), % | 0 | |
| 0 to 0.010 |