SAE-AISI A7 Steel vs. S21904 Stainless Steel
Both SAE-AISI A7 steel and S21904 stainless steel are iron alloys. They have 70% of their average alloy composition in common. There are 22 material properties with values for both materials. Properties with values for just one material (11, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI A7 steel and the bottom bar is S21904 stainless steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Poisson's Ratio | 0.29 | |
| 0.28 |
| Shear Modulus, GPa | 72 | |
| 78 |
| Tensile Strength: Ultimate (UTS), MPa | 800 to 2150 | |
| 700 to 1000 |
Thermal Properties
| Latent Heat of Fusion, J/g | 260 | |
| 290 |
| Melting Completion (Liquidus), °C | 1470 | |
| 1400 |
| Melting Onset (Solidus), °C | 1430 | |
| 1350 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 480 |
| Thermal Conductivity, W/m-K | 37 | |
| 14 |
| Thermal Expansion, µm/m-K | 12 | |
| 17 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 10 | |
| 15 |
| Density, g/cm3 | 7.7 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 13 | |
| 3.0 |
| Embodied Energy, MJ/kg | 200 | |
| 43 |
| Embodied Water, L/kg | 100 | |
| 160 |
Common Calculations
| PREN (Pitting Resistance) | 11 | |
| 25 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 25 | |
| 25 |
| Strength to Weight: Axial, points | 29 to 77 | |
| 25 to 36 |
| Strength to Weight: Bending, points | 25 to 48 | |
| 23 to 29 |
| Thermal Diffusivity, mm2/s | 10 | |
| 3.8 |
| Thermal Shock Resistance, points | 27 to 72 | |
| 15 to 21 |
Alloy Composition
| Carbon (C), % | 2.0 to 2.9 | |
| 0 to 0.040 |
| Chromium (Cr), % | 5.0 to 5.8 | |
| 19 to 21.5 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 81.4 to 87.7 | |
| 59.5 to 67.4 |
| Manganese (Mn), % | 0 to 0.8 | |
| 8.0 to 10 |
| Molybdenum (Mo), % | 0.9 to 1.4 | |
| 0 |
| Nickel (Ni), % | 0 to 0.3 | |
| 5.5 to 7.5 |
| Nitrogen (N), % | 0 | |
| 0.15 to 0.4 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.045 |
| Silicon (Si), % | 0 to 0.5 | |
| 0 to 1.0 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 0.5 to 1.5 | |
| 0 |
| Vanadium (V), % | 3.9 to 5.2 | |
| 0 |