Annealed SAE-AISI H21 vs. Annealed SAE-AISI M4
Both annealed SAE-AISI H21 and annealed SAE-AISI M4 are iron alloys. Both are furnished in the annealed condition. They have 90% of their average alloy composition in common.
For each property being compared, the top bar is annealed SAE-AISI H21 and the bottom bar is annealed SAE-AISI M4.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 220 | |
| 230 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 200 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Rockwell B Hardness | 97 | |
| 100 |
| Shear Modulus, GPa | 76 | |
| 76 |
| Tensile Strength: Ultimate (UTS), MPa | 720 | |
| 770 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 260 |
| Melting Completion (Liquidus), °C | 1630 | |
| 1610 |
| Melting Onset (Solidus), °C | 1580 | |
| 1560 |
| Specific Heat Capacity, J/kg-K | 440 | |
| 440 |
| Thermal Conductivity, W/m-K | 27 | |
| 25 |
| Thermal Expansion, µm/m-K | 11 | |
| 12 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 23 | |
| 25 |
| Density, g/cm3 | 8.5 | |
| 8.3 |
| Embodied Carbon, kg CO2/kg material | 4.5 | |
| 14 |
| Embodied Energy, MJ/kg | 68 | |
| 210 |
| Embodied Water, L/kg | 72 | |
| 110 |
Common Calculations
| PREN (Pitting Resistance) | 19 | |
| 30 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 23 | |
| 23 |
| Strength to Weight: Axial, points | 23 | |
| 26 |
| Strength to Weight: Bending, points | 21 | |
| 23 |
| Thermal Diffusivity, mm2/s | 7.1 | |
| 6.9 |
| Thermal Shock Resistance, points | 24 | |
| 24 |
Alloy Composition
| Carbon (C), % | 0.28 to 0.36 | |
| 1.3 to 1.4 |
| Chromium (Cr), % | 3.0 to 3.8 | |
| 3.8 to 4.8 |
| Copper (Cu), % | 0 to 0.25 | |
| 0 to 0.25 |
| Iron (Fe), % | 87.6 to 93.8 | |
| 75.9 to 81.4 |
| Manganese (Mn), % | 0.15 to 0.4 | |
| 0.15 to 0.4 |
| Molybdenum (Mo), % | 0 | |
| 4.3 to 5.5 |
| Nickel (Ni), % | 0 to 0.3 | |
| 0 to 0.3 |
| Phosphorus (P), % | 0 to 0.030 | |
| 0 to 0.030 |
| Silicon (Si), % | 0.15 to 0.5 | |
| 0.2 to 0.45 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.030 |
| Tungsten (W), % | 8.5 to 10 | |
| 5.3 to 6.5 |
| Vanadium (V), % | 0.3 to 0.6 | |
| 3.8 to 4.5 |