S21904 Stainless Steel vs. AISI 321 Stainless Steel
Both S21904 stainless steel and AISI 321 stainless steel are iron alloys. They have 89% of their average alloy composition in common.
For each property being compared, the top bar is S21904 stainless steel and the bottom bar is AISI 321 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 210 to 300 | |
| 170 to 210 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 200 |
| Elongation at Break, % | 17 to 51 | |
| 34 to 50 |
| Fatigue Strength, MPa | 380 to 550 | |
| 220 to 270 |
| Poisson's Ratio | 0.28 | |
| 0.28 |
| Shear Modulus, GPa | 78 | |
| 77 |
| Shear Strength, MPa | 510 to 620 | |
| 420 to 460 |
| Tensile Strength: Ultimate (UTS), MPa | 700 to 1000 | |
| 590 to 690 |
| Tensile Strength: Yield (Proof), MPa | 390 to 910 | |
| 220 to 350 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 290 |
| Maximum Temperature: Corrosion, °C | 430 | |
| 480 |
| Maximum Temperature: Mechanical, °C | 980 | |
| 870 |
| Melting Completion (Liquidus), °C | 1400 | |
| 1430 |
| Melting Onset (Solidus), °C | 1350 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 480 |
| Thermal Conductivity, W/m-K | 14 | |
| 16 |
| Thermal Expansion, µm/m-K | 17 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.5 | |
| 2.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.9 | |
| 2.7 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 15 | |
| 16 |
| Density, g/cm3 | 7.7 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.0 | |
| 3.2 |
| Embodied Energy, MJ/kg | 43 | |
| 45 |
| Embodied Water, L/kg | 160 | |
| 140 |
Common Calculations
| PREN (Pitting Resistance) | 25 | |
| 19 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 160 to 310 | |
| 190 to 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 380 to 2070 | |
| 130 to 310 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 25 to 36 | |
| 21 to 25 |
| Strength to Weight: Bending, points | 23 to 29 | |
| 20 to 22 |
| Thermal Diffusivity, mm2/s | 3.8 | |
| 4.1 |
| Thermal Shock Resistance, points | 15 to 21 | |
| 13 to 15 |
Alloy Composition
| Carbon (C), % | 0 to 0.040 | |
| 0 to 0.080 |
| Chromium (Cr), % | 19 to 21.5 | |
| 17 to 19 |
| Iron (Fe), % | 59.5 to 67.4 | |
| 65.3 to 74 |
| Manganese (Mn), % | 8.0 to 10 | |
| 0 to 2.0 |
| Nickel (Ni), % | 5.5 to 7.5 | |
| 9.0 to 12 |
| Nitrogen (N), % | 0.15 to 0.4 | |
| 0 to 0.1 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 1.0 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 | |
| 0 to 0.7 |