SAE-AISI 8740 Steel vs. R30075 Cobalt
SAE-AISI 8740 steel belongs to the iron alloys classification, while R30075 cobalt belongs to the cobalt alloys. There are 27 material properties with values for both materials. Properties with values for just one material (5, in this case) are not shown.
For each property being compared, the top bar is SAE-AISI 8740 steel and the bottom bar is R30075 cobalt.
Metric UnitsUS Customary Units
Mechanical Properties
Elastic (Young's, Tensile) Modulus, GPa | 190 | |
210 to 250 |
Elongation at Break, % | 11 to 23 | |
12 |
Fatigue Strength, MPa | 270 to 350 | |
250 to 840 |
Poisson's Ratio | 0.29 | |
0.29 |
Shear Modulus, GPa | 73 | |
82 to 98 |
Tensile Strength: Ultimate (UTS), MPa | 580 to 670 | |
780 to 1280 |
Tensile Strength: Yield (Proof), MPa | 380 to 570 | |
480 to 840 |
Thermal Properties
Latent Heat of Fusion, J/g | 250 | |
320 |
Melting Completion (Liquidus), °C | 1460 | |
1360 |
Melting Onset (Solidus), °C | 1420 | |
1290 |
Specific Heat Capacity, J/kg-K | 470 | |
450 |
Thermal Conductivity, W/m-K | 39 | |
13 |
Thermal Expansion, µm/m-K | 13 | |
12 |
Electrical Properties
Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
2.0 |
Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
2.1 |
Otherwise Unclassified Properties
Density, g/cm3 | 7.8 | |
8.4 |
Embodied Carbon, kg CO2/kg material | 1.5 | |
8.1 |
Embodied Energy, MJ/kg | 20 | |
110 |
Embodied Water, L/kg | 50 | |
530 |
Common Calculations
Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 71 to 120 | |
84 to 140 |
Resilience: Unit (Modulus of Resilience), kJ/m3 | 390 to 850 | |
560 to 1410 |
Stiffness to Weight: Axial, points | 13 | |
14 to 17 |
Stiffness to Weight: Bending, points | 24 | |
24 to 25 |
Strength to Weight: Axial, points | 20 to 24 | |
26 to 42 |
Strength to Weight: Bending, points | 20 to 22 | |
22 to 31 |
Thermal Diffusivity, mm2/s | 10 | |
3.5 |
Thermal Shock Resistance, points | 17 to 20 | |
21 to 29 |
Alloy Composition
Aluminum (Al), % | 0 | |
0 to 0.1 |
Boron (B), % | 0 | |
0 to 0.010 |
Carbon (C), % | 0.38 to 0.43 | |
0 to 0.35 |
Chromium (Cr), % | 0.4 to 0.6 | |
27 to 30 |
Cobalt (Co), % | 0 | |
58.7 to 68 |
Iron (Fe), % | 96.5 to 97.7 | |
0 to 0.75 |
Manganese (Mn), % | 0.75 to 1.0 | |
0 to 1.0 |
Molybdenum (Mo), % | 0.2 to 0.3 | |
5.0 to 7.0 |
Nickel (Ni), % | 0.4 to 0.7 | |
0 to 0.5 |
Nitrogen (N), % | 0 | |
0 to 0.25 |
Phosphorus (P), % | 0 to 0.035 | |
0 to 0.020 |
Silicon (Si), % | 0.15 to 0.35 | |
0 to 1.0 |
Sulfur (S), % | 0 to 0.040 | |
0 to 0.010 |
Titanium (Ti), % | 0 | |
0 to 0.1 |
Tungsten (W), % | 0 | |
0 to 0.2 |