SAE-AISI H21 Steel vs. SAE-AISI 4340 Steel
Both SAE-AISI H21 steel and SAE-AISI 4340 steel are iron alloys. They have a moderately high 93% of their average alloy composition in common. There are 21 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 H21 steel and the bottom bar is SAE-AISI 4340 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 76 | |
| 73 |
| Tensile Strength: Ultimate (UTS), MPa | 720 to 1790 | |
| 690 to 1280 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Melting Completion (Liquidus), °C | 1630 | |
| 1460 |
| Melting Onset (Solidus), °C | 1580 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 440 | |
| 470 |
| Thermal Conductivity, W/m-K | 27 | |
| 44 |
| Thermal Expansion, µm/m-K | 11 | |
| 13 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 23 | |
| 3.5 |
| Density, g/cm3 | 8.5 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 4.5 | |
| 1.7 |
| Embodied Energy, MJ/kg | 68 | |
| 22 |
| Embodied Water, L/kg | 72 | |
| 53 |
Common Calculations
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 23 | |
| 24 |
| Strength to Weight: Axial, points | 23 to 58 | |
| 24 to 45 |
| Strength to Weight: Bending, points | 21 to 38 | |
| 22 to 33 |
| Thermal Diffusivity, mm2/s | 7.1 | |
| 12 |
| Thermal Shock Resistance, points | 24 to 59 | |
| 20 to 38 |
Alloy Composition
| Carbon (C), % | 0.28 to 0.36 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 3.0 to 3.8 | |
| 0.7 to 0.9 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 |
| Iron (Fe), % | 87.6 to 93.8 | |
| 95.1 to 96.3 |
| Manganese (Mn), % | 0.15 to 0.4 | |
| 0.6 to 0.8 |
| Molybdenum (Mo), % | 0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 0 to 0.3 | |
| 1.7 to 2.0 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.035 |
| Silicon (Si), % | 0.15 to 0.5 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.040 |
| Tungsten (W), % | 8.5 to 10 | |
| 0 |
| Vanadium (V), % | 0.3 to 0.6 | |
| 0 |