ASTM A387 Grade 91 Class 2 vs. AISI 420 Stainless Steel
Both ASTM A387 grade 91 class 2 and AISI 420 stainless steel are iron alloys. They have a very high 95% 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 420 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 | |
| 190 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 20 | |
| 8.0 to 15 |
| Fatigue Strength, MPa | 330 | |
| 220 to 670 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 75 | |
| 76 |
| Shear Strength, MPa | 420 | |
| 420 to 1010 |
| Tensile Strength: Ultimate (UTS), MPa | 670 | |
| 690 to 1720 |
| Tensile Strength: Yield (Proof), MPa | 470 | |
| 380 to 1310 |
Thermal Properties
| Latent Heat of Fusion, J/g | 270 | |
| 280 |
| Maximum Temperature: Mechanical, °C | 600 | |
| 620 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1510 |
| Melting Onset (Solidus), °C | 1420 | |
| 1450 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 26 | |
| 27 |
| Thermal Expansion, µm/m-K | 13 | |
| 10 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 8.9 | |
| 3.0 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 10 | |
| 3.5 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 7.0 | |
| 7.5 |
| Density, g/cm3 | 7.8 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 2.6 | |
| 2.0 |
| Embodied Energy, MJ/kg | 37 | |
| 28 |
| Embodied Water, L/kg | 88 | |
| 100 |
Common Calculations
| PREN (Pitting Resistance) | 13 | |
| 14 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 88 to 130 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 580 | |
| 380 to 4410 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 24 | |
| 25 to 62 |
| Strength to Weight: Bending, points | 22 | |
| 22 to 41 |
| Thermal Diffusivity, mm2/s | 6.9 | |
| 7.3 |
| Thermal Shock Resistance, points | 19 | |
| 25 to 62 |
Alloy Composition
| Aluminum (Al), % | 0 to 0.020 | |
| 0 |
| Carbon (C), % | 0.080 to 0.12 | |
| 0.15 to 0.4 |
| Chromium (Cr), % | 8.0 to 9.5 | |
| 12 to 14 |
| Iron (Fe), % | 87.3 to 90.3 | |
| 82.3 to 87.9 |
| Manganese (Mn), % | 0.3 to 0.6 | |
| 0 to 1.0 |
| Molybdenum (Mo), % | 0.85 to 1.1 | |
| 0 to 0.5 |
| Nickel (Ni), % | 0 to 0.4 | |
| 0 to 0.75 |
| Niobium (Nb), % | 0.060 to 0.1 | |
| 0 |
| Nitrogen (N), % | 0.030 to 0.070 | |
| 0 |
| Phosphorus (P), % | 0 to 0.020 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.2 to 0.5 | |
| 0 to 1.0 |
| 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 |