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ASTM A372 Grade K Steel vs. G-CoCr28 Cobalt

ASTM A372 grade K steel belongs to the iron alloys classification, while G-CoCr28 cobalt belongs to the cobalt alloys. They have a modest 21% of their average alloy composition in common, which, by itself, doesn't mean much. 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 ASTM A372 grade K 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, % 23
6.7
Fatigue Strength, MPa 440
130
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 73
83
Tensile Strength: Ultimate (UTS), MPa 780
560
Tensile Strength: Yield (Proof), MPa 620
260

Thermal Properties

Latent Heat of Fusion, J/g 250
320
Maximum Temperature: Mechanical, °C 440
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 48
8.5
Thermal Expansion, µm/m-K 13
14

Otherwise Unclassified Properties

Base Metal Price, % relative 4.4
100
Density, g/cm3 7.9
8.1
Embodied Carbon, kg CO2/kg material 1.8
6.2
Embodied Energy, MJ/kg 24
84
Embodied Water, L/kg 57
440

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 160
31
Resilience: Unit (Modulus of Resilience), kJ/m3 1010
160
Stiffness to Weight: Axial, points 13
15
Stiffness to Weight: Bending, points 24
24
Strength to Weight: Axial, points 27
19
Strength to Weight: Bending, points 24
19
Thermal Diffusivity, mm2/s 13
2.2
Thermal Shock Resistance, points 23
14

Alloy Composition

Carbon (C), % 0 to 0.18
0.050 to 0.25
Chromium (Cr), % 1.0 to 1.8
27 to 30
Cobalt (Co), % 0
48 to 52
Iron (Fe), % 93.4 to 96.6
9.7 to 24.5
Manganese (Mn), % 0.1 to 0.4
0 to 1.5
Molybdenum (Mo), % 0.2 to 0.6
0 to 0.5
Nickel (Ni), % 2.0 to 3.3
0 to 4.0
Niobium (Nb), % 0
0 to 0.5
Phosphorus (P), % 0 to 0.015
0 to 0.040
Silicon (Si), % 0.15 to 0.35
0.5 to 1.5
Sulfur (S), % 0 to 0.010
0 to 0.030