SAE-AISI 8740 Steel vs. Type 4 Niobium
SAE-AISI 8740 steel belongs to the iron alloys classification, while Type 4 niobium belongs to the otherwise unclassified metals. There are 21 material properties with values for both materials. Properties with values for just one material (10, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 8740 steel and the bottom bar is Type 4 niobium.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 to 200 | |
| 120 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 110 |
| Elongation at Break, % | 11 to 23 | |
| 23 |
| Poisson's Ratio | 0.29 | |
| 0.4 |
| Shear Modulus, GPa | 73 | |
| 38 |
| Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
| 220 |
| Tensile Strength: Yield (Proof), MPa | 380 to 570 | |
| 140 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 310 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 270 |
| Thermal Conductivity, W/m-K | 39 | |
| 42 |
| Thermal Expansion, µm/m-K | 13 | |
| 7.3 |
Otherwise Unclassified Properties
| Density, g/cm3 | 7.8 | |
| 8.6 |
| Embodied Water, L/kg | 50 | |
| 160 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 71 to 120 | |
| 44 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 to 850 | |
| 93 |
| Stiffness to Weight: Axial, points | 13 | |
| 6.8 |
| Stiffness to Weight: Bending, points | 24 | |
| 18 |
| Strength to Weight: Axial, points | 20 to 24 | |
| 7.2 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 9.5 |
| Thermal Diffusivity, mm2/s | 10 | |
| 18 |
| Thermal Shock Resistance, points | 17 to 20 | |
| 21 |
Alloy Composition
| Carbon (C), % | 0.38 to 0.43 | |
| 0 to 0.010 |
| Chromium (Cr), % | 0.4 to 0.6 | |
| 0 |
| Hafnium (Hf), % | 0 | |
| 0 to 0.020 |
| Hydrogen (H), % | 0 | |
| 0 to 0.0015 |
| Iron (Fe), % | 96.5 to 97.7 | |
| 0 to 0.010 |
| Manganese (Mn), % | 0.75 to 1.0 | |
| 0 |
| Molybdenum (Mo), % | 0.2 to 0.3 | |
| 0 to 0.050 |
| Nickel (Ni), % | 0.4 to 0.7 | |
| 0 to 0.0050 |
| Niobium (Nb), % | 0 | |
| 98.1 to 99.2 |
| Nitrogen (N), % | 0 | |
| 0 to 0.010 |
| Oxygen (O), % | 0 | |
| 0 to 0.025 |
| Phosphorus (P), % | 0 to 0.035 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 0.0050 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 |
| Tantalum (Ta), % | 0 | |
| 0 to 0.5 |
| Titanium (Ti), % | 0 | |
| 0 to 0.020 |
| Tungsten (W), % | 0 | |
| 0 to 0.050 |
| Zirconium (Zr), % | 0 | |
| 0.8 to 1.2 |