SAE-AISI 4320 Steel vs. S81921 Stainless Steel
Both SAE-AISI 4320 steel and S81921 stainless steel are iron alloys. They have 75% of their average alloy composition in common. There are 31 material properties with values for both materials. Properties with values for just one material (3, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4320 steel and the bottom bar is S81921 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 160 to 240 | |
| 260 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 21 to 29 | |
| 29 |
| Fatigue Strength, MPa | 320 | |
| 370 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 73 | |
| 79 |
| Shear Strength, MPa | 370 to 500 | |
| 460 |
| Tensile Strength: Ultimate (UTS), MPa | 570 to 790 | |
| 710 |
| Tensile Strength: Yield (Proof), MPa | 430 to 460 | |
| 500 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 290 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 990 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1430 |
| Melting Onset (Solidus), °C | 1420 | |
| 1390 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 46 | |
| 15 |
| Thermal Expansion, µm/m-K | 11 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.4 | |
| 2.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.5 | |
| 2.5 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.4 | |
| 14 |
| Density, g/cm3 | 7.9 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 1.7 | |
| 2.9 |
| Embodied Energy, MJ/kg | 22 | |
| 41 |
| Embodied Water, L/kg | 52 | |
| 150 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 140 to 150 | |
| 180 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 480 to 560 | |
| 630 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 20 to 28 | |
| 25 |
| Strength to Weight: Bending, points | 19 to 24 | |
| 23 |
| Thermal Diffusivity, mm2/s | 13 | |
| 4.0 |
| Thermal Shock Resistance, points | 19 to 27 | |
| 20 |
Alloy Composition
| Carbon (C), % | 0.17 to 0.22 | |
| 0 to 0.030 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 19 to 22 |
| Iron (Fe), % | 95.8 to 97 | |
| 66.7 to 75.9 |
| Manganese (Mn), % | 0.45 to 0.65 | |
| 2.0 to 4.0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 1.0 to 2.0 |
| Nickel (Ni), % | 1.7 to 2.0 | |
| 2.0 to 4.0 |
| Nitrogen (N), % | 0 | |
| 0.14 to 0.2 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.040 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |