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SAE-AISI A4 Steel vs. G-CoCr28 Cobalt

SAE-AISI A4 steel belongs to the iron alloys classification, while G-CoCr28 cobalt belongs to the cobalt alloys. They have a modest 20% of their average alloy composition in common, which, by itself, doesn't mean much. There are 21 material properties with values for both materials. Properties with values for just one material (9, in this case) are not shown.

For each property being compared, the top bar is SAE-AISI A4 steel and the bottom bar is G-CoCr28 cobalt.

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa 190
210
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 73
83
Tensile Strength: Ultimate (UTS), MPa 710 to 2050
560

Thermal Properties

Latent Heat of Fusion, J/g 250
320
Melting Completion (Liquidus), °C 1450
1330
Melting Onset (Solidus), °C 1410
1270
Specific Heat Capacity, J/kg-K 470
470
Thermal Conductivity, W/m-K 40
8.5
Thermal Expansion, µm/m-K 12
14

Otherwise Unclassified Properties

Base Metal Price, % relative 3.9
100
Density, g/cm3 7.8
8.1
Embodied Carbon, kg CO2/kg material 1.8
6.2
Embodied Energy, MJ/kg 24
84
Embodied Water, L/kg 59
440

Common Calculations

Stiffness to Weight: Axial, points 13
15
Stiffness to Weight: Bending, points 24
24
Strength to Weight: Axial, points 25 to 73
19
Strength to Weight: Bending, points 23 to 46
19
Thermal Diffusivity, mm2/s 11
2.2
Thermal Shock Resistance, points 23 to 67
14

Alloy Composition

Carbon (C), % 1.0 to 1.1
0.050 to 0.25
Chromium (Cr), % 0.9 to 2.2
27 to 30
Cobalt (Co), % 0
48 to 52
Copper (Cu), % 0 to 0.25
0
Iron (Fe), % 92 to 95.5
9.7 to 24.5
Manganese (Mn), % 1.8 to 2.2
0 to 1.5
Molybdenum (Mo), % 0.9 to 1.4
0 to 0.5
Nickel (Ni), % 0 to 0.3
0 to 4.0
Niobium (Nb), % 0
0 to 0.5
Phosphorus (P), % 0 to 0.030
0 to 0.040
Silicon (Si), % 0 to 0.5
0.5 to 1.5
Sulfur (S), % 0 to 0.030
0 to 0.030