SAE-AISI 4340M Steel vs. S21904 Stainless Steel
Both SAE-AISI 4340M steel and S21904 stainless steel are iron alloys. They have 67% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 4340M steel and the bottom bar is S21904 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 710 | |
| 210 to 300 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 6.0 | |
| 17 to 51 |
| Fatigue Strength, MPa | 690 | |
| 380 to 550 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 72 | |
| 78 |
| Shear Strength, MPa | 1360 | |
| 510 to 620 |
| Tensile Strength: Ultimate (UTS), MPa | 2340 | |
| 700 to 1000 |
| Tensile Strength: Yield (Proof), MPa | 1240 | |
| 390 to 910 |
Thermal Properties
| Latent Heat of Fusion, J/g | 280 | |
| 290 |
| Maximum Temperature: Mechanical, °C | 430 | |
| 980 |
| Melting Completion (Liquidus), °C | 1440 | |
| 1400 |
| Melting Onset (Solidus), °C | 1400 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 480 |
| Thermal Conductivity, W/m-K | 38 | |
| 14 |
| Thermal Expansion, µm/m-K | 13 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.8 | |
| 2.5 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 9.1 | |
| 2.9 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 3.9 | |
| 15 |
| Density, g/cm3 | 7.8 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 1.9 | |
| 3.0 |
| Embodied Energy, MJ/kg | 26 | |
| 43 |
| Embodied Water, L/kg | 55 | |
| 160 |
Common Calculations
| PREN (Pitting Resistance) | 2.2 | |
| 25 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 120 | |
| 160 to 310 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 4120 | |
| 380 to 2070 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 84 | |
| 25 to 36 |
| Strength to Weight: Bending, points | 51 | |
| 23 to 29 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.8 |
| Thermal Shock Resistance, points | 70 | |
| 15 to 21 |
Alloy Composition
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.040 |
| Chromium (Cr), % | 0.7 to 1.0 | |
| 19 to 21.5 |
| Iron (Fe), % | 93.3 to 94.8 | |
| 59.5 to 67.4 |
| Manganese (Mn), % | 0.65 to 0.9 | |
| 8.0 to 10 |
| Molybdenum (Mo), % | 0.35 to 0.45 | |
| 0 |
| Nickel (Ni), % | 1.7 to 2.0 | |
| 5.5 to 7.5 |
| Nitrogen (N), % | 0 | |
| 0.15 to 0.4 |
| Phosphorus (P), % | 0 to 0.012 | |
| 0 to 0.045 |
| Silicon (Si), % | 1.5 to 1.8 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.012 | |
| 0 to 0.030 |
| Vanadium (V), % | 0.050 to 0.1 | |
| 0 |