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SAE-AISI 8740 Steel vs. G-CoCr28 Cobalt

SAE-AISI 8740 steel belongs to the iron alloys classification, while G-CoCr28 cobalt belongs to the cobalt alloys. There are 27 material properties with values for both materials. Properties with values for just one material (4, in this case) are not shown.

For each property being compared, the top bar is SAE-AISI 8740 steel and the bottom bar is G-CoCr28 cobalt.

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa 190
210
Elongation at Break, % 11 to 23
6.7
Fatigue Strength, MPa 270 to 350
130
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 73
83
Tensile Strength: Ultimate (UTS), MPa 580 to 670
560
Tensile Strength: Yield (Proof), MPa 380 to 570
260

Thermal Properties

Latent Heat of Fusion, J/g 250
320
Maximum Temperature: Mechanical, °C 410
1200
Melting Completion (Liquidus), °C 1460
1330
Melting Onset (Solidus), °C 1420
1270
Specific Heat Capacity, J/kg-K 470
470
Thermal Conductivity, W/m-K 39
8.5
Thermal Expansion, µm/m-K 13
14

Otherwise Unclassified Properties

Base Metal Price, % relative 2.6
100
Density, g/cm3 7.8
8.1
Embodied Carbon, kg CO2/kg material 1.5
6.2
Embodied Energy, MJ/kg 20
84
Embodied Water, L/kg 50
440

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 71 to 120
31
Resilience: Unit (Modulus of Resilience), kJ/m3 390 to 850
160
Stiffness to Weight: Axial, points 13
15
Stiffness to Weight: Bending, points 24
24
Strength to Weight: Axial, points 20 to 24
19
Strength to Weight: Bending, points 20 to 22
19
Thermal Diffusivity, mm2/s 10
2.2
Thermal Shock Resistance, points 17 to 20
14

Alloy Composition

Carbon (C), % 0.38 to 0.43
0.050 to 0.25
Chromium (Cr), % 0.4 to 0.6
27 to 30
Cobalt (Co), % 0
48 to 52
Iron (Fe), % 96.5 to 97.7
9.7 to 24.5
Manganese (Mn), % 0.75 to 1.0
0 to 1.5
Molybdenum (Mo), % 0.2 to 0.3
0 to 0.5
Nickel (Ni), % 0.4 to 0.7
0 to 4.0
Niobium (Nb), % 0
0 to 0.5
Phosphorus (P), % 0 to 0.035
0 to 0.040
Silicon (Si), % 0.15 to 0.35
0.5 to 1.5
Sulfur (S), % 0 to 0.040
0 to 0.030