Hot Finished AISI 309 vs. Hot Finished AISI 321
Both hot finished AISI 309 and hot finished AISI 321 are iron alloys. Both are furnished in the hot worked condition. They have a moderately high 92% of their average alloy composition in common.
For each property being compared, the top bar is hot finished AISI 309 and the bottom bar is hot finished AISI 321.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 180 | |
| 170 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 200 |
| Elongation at Break, % | 47 | |
| 50 |
| Fatigue Strength, MPa | 250 | |
| 220 |
| Poisson's Ratio | 0.27 | |
| 0.28 |
| Rockwell B Hardness | 84 | |
| 77 |
| Shear Modulus, GPa | 78 | |
| 77 |
| Shear Strength, MPa | 420 | |
| 420 |
| Tensile Strength: Ultimate (UTS), MPa | 600 | |
| 590 |
| Tensile Strength: Yield (Proof), MPa | 260 | |
| 220 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 290 |
| Maximum Temperature: Corrosion, °C | 440 | |
| 480 |
| Maximum Temperature: Mechanical, °C | 980 | |
| 870 |
| Melting Completion (Liquidus), °C | 1450 | |
| 1430 |
| Melting Onset (Solidus), °C | 1400 | |
| 1400 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 480 |
| Thermal Conductivity, W/m-K | 16 | |
| 16 |
| Thermal Expansion, µm/m-K | 15 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.2 | |
| 2.4 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.5 | |
| 2.7 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 19 | |
| 16 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.6 | |
| 3.2 |
| Embodied Energy, MJ/kg | 51 | |
| 45 |
| Embodied Water, L/kg | 170 | |
| 140 |
Common Calculations
| PREN (Pitting Resistance) | 23 | |
| 19 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 230 | |
| 230 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 170 | |
| 130 |
| Stiffness to Weight: Axial, points | 14 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 21 | |
| 21 |
| Strength to Weight: Bending, points | 20 | |
| 20 |
| Thermal Diffusivity, mm2/s | 4.3 | |
| 4.1 |
| Thermal Shock Resistance, points | 14 | |
| 13 |
Alloy Composition
| Carbon (C), % | 0 to 0.2 | |
| 0 to 0.080 |
| Chromium (Cr), % | 22 to 24 | |
| 17 to 19 |
| Iron (Fe), % | 58 to 66 | |
| 65.3 to 74 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0 to 2.0 |
| Nickel (Ni), % | 12 to 15 | |
| 9.0 to 12 |
| Nitrogen (N), % | 0 | |
| 0 to 0.1 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 0.75 | |
| 0 to 0.75 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Titanium (Ti), % | 0 | |
| 0 to 0.7 |