AISI 321 Stainless Steel vs. SAE-AISI 4340 Steel
Both AISI 321 stainless steel and SAE-AISI 4340 steel are iron alloys. They have 73% of their average alloy composition in common. There are 31 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 AISI 321 stainless steel and the bottom bar is SAE-AISI 4340 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 to 210 | |
| 210 to 360 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Elongation at Break, % | 34 to 50 | |
| 12 to 22 |
| Fatigue Strength, MPa | 220 to 270 | |
| 330 to 740 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 77 | |
| 73 |
| Shear Strength, MPa | 420 to 460 | |
| 430 to 770 |
| Tensile Strength: Ultimate (UTS), MPa | 590 to 690 | |
| 690 to 1280 |
| Tensile Strength: Yield (Proof), MPa | 220 to 350 | |
| 470 to 1150 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 870 | |
| 430 |
| Melting Completion (Liquidus), °C | 1430 | |
| 1460 |
| Melting Onset (Solidus), °C | 1400 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 470 |
| Thermal Conductivity, W/m-K | 16 | |
| 44 |
| Thermal Expansion, µm/m-K | 17 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.4 | |
| 7.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.7 | |
| 8.6 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 16 | |
| 3.5 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.2 | |
| 1.7 |
| Embodied Energy, MJ/kg | 45 | |
| 22 |
| Embodied Water, L/kg | 140 | |
| 53 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 190 to 230 | |
| 79 to 170 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 130 to 310 | |
| 590 to 3490 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 21 to 25 | |
| 24 to 45 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 22 to 33 |
| Thermal Diffusivity, mm2/s | 4.1 | |
| 12 |
| Thermal Shock Resistance, points | 13 to 15 | |
| 20 to 38 |
Alloy Composition
| Carbon (C), % | 0 to 0.080 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 17 to 19 | |
| 0.7 to 0.9 |
| Iron (Fe), % | 65.3 to 74 | |
| 95.1 to 96.3 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0.6 to 0.8 |
| Molybdenum (Mo), % | 0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 9.0 to 12 | |
| 1.7 to 2.0 |
| Nitrogen (N), % | 0 to 0.1 | |
| 0 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.035 |
| Silicon (Si), % | 0 to 0.75 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.040 |
| Titanium (Ti), % | 0 to 0.7 | |
| 0 |