MakeItFrom.com
Menu (ESC)

SAE-AISI 8740 Steel vs. R30605 Cobalt

SAE-AISI 8740 steel belongs to the iron alloys classification, while R30605 cobalt belongs to the cobalt alloys. There are 25 material properties with values for both materials. Properties with values for just one material (6, in this case) are not shown.

For each property being compared, the top bar is SAE-AISI 8740 steel and the bottom bar is R30605 cobalt.

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa 190
210
Elongation at Break, % 11 to 23
34
Fatigue Strength, MPa 270 to 350
260 to 590
Poisson's Ratio 0.29
0.29
Shear Modulus, GPa 73
81
Tensile Strength: Ultimate (UTS), MPa 580 to 670
1130 to 1900
Tensile Strength: Yield (Proof), MPa 380 to 570
470 to 1600

Thermal Properties

Latent Heat of Fusion, J/g 250
290
Melting Completion (Liquidus), °C 1460
1410
Melting Onset (Solidus), °C 1420
1330
Specific Heat Capacity, J/kg-K 470
410
Thermal Conductivity, W/m-K 39
9.6
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
1.8

Otherwise Unclassified Properties

Density, g/cm3 7.8
9.6
Embodied Carbon, kg CO2/kg material 1.5
9.8
Embodied Energy, MJ/kg 20
140
Embodied Water, L/kg 50
450

Common Calculations

Stiffness to Weight: Axial, points 13
12
Stiffness to Weight: Bending, points 24
21
Strength to Weight: Axial, points 20 to 24
33 to 55
Strength to Weight: Bending, points 20 to 22
25 to 36
Thermal Diffusivity, mm2/s 10
2.5
Thermal Shock Resistance, points 17 to 20
31 to 52

Alloy Composition

Carbon (C), % 0.38 to 0.43
0.050 to 0.15
Chromium (Cr), % 0.4 to 0.6
19 to 21
Cobalt (Co), % 0
46.4 to 57
Iron (Fe), % 96.5 to 97.7
0 to 3.0
Manganese (Mn), % 0.75 to 1.0
1.0 to 2.0
Molybdenum (Mo), % 0.2 to 0.3
0
Nickel (Ni), % 0.4 to 0.7
9.0 to 11
Phosphorus (P), % 0 to 0.035
0 to 0.040
Silicon (Si), % 0.15 to 0.35
0 to 0.4
Sulfur (S), % 0 to 0.040
0 to 0.030
Tungsten (W), % 0
14 to 16

Comparable Variants