SAE-AISI 4718 Steel vs. S21800 Stainless Steel
Both SAE-AISI 4718 steel and S21800 stainless steel are iron alloys. Both are furnished in the annealed condition. They have 65% of their average alloy composition in common. There are 27 material properties with values for both materials. Properties with values for just one material (8, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4718 steel and the bottom bar is S21800 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 150 | |
| 210 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 24 | |
| 40 |
| Fatigue Strength, MPa | 270 | |
| 330 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 73 | |
| 75 |
| Shear Strength, MPa | 330 | |
| 510 |
| Tensile Strength: Ultimate (UTS), MPa | 510 | |
| 740 |
| Tensile Strength: Yield (Proof), MPa | 370 | |
| 390 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 340 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 900 |
| Melting Completion (Liquidus), °C | 1460 | |
| 1360 |
| Melting Onset (Solidus), °C | 1420 | |
| 1310 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 500 |
| Thermal Expansion, µm/m-K | 11 | |
| 16 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.0 | |
| 15 |
| Density, g/cm3 | 7.9 | |
| 7.5 |
| Embodied Carbon, kg CO2/kg material | 1.6 | |
| 3.1 |
| Embodied Energy, MJ/kg | 21 | |
| 45 |
| Embodied Water, L/kg | 51 | |
| 150 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 | |
| 250 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 360 | |
| 390 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 26 |
| Strength to Weight: Axial, points | 18 | |
| 27 |
| Strength to Weight: Bending, points | 18 | |
| 24 |
| Thermal Shock Resistance, points | 17 | |
| 17 |
Alloy Composition
| Carbon (C), % | 0.16 to 0.21 | |
| 0 to 0.1 |
| Chromium (Cr), % | 0.35 to 0.55 | |
| 16 to 18 |
| Iron (Fe), % | 96.3 to 97.4 | |
| 59.1 to 65.4 |
| Manganese (Mn), % | 0.7 to 0.9 | |
| 7.0 to 9.0 |
| Molybdenum (Mo), % | 0.3 to 0.4 | |
| 0 |
| Nickel (Ni), % | 0.9 to 1.2 | |
| 8.0 to 9.0 |
| Nitrogen (N), % | 0 | |
| 0.080 to 0.18 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 to 0.060 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 3.5 to 4.5 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.030 |