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S21640 Stainless Steel vs. G-CoCr28 Cobalt

S21640 stainless steel belongs to the iron alloys classification, while G-CoCr28 cobalt belongs to the cobalt alloys. They have a modest 39% 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 (6, in this case) are not shown.

For each property being compared, the top bar is S21640 stainless steel and the bottom bar is G-CoCr28 cobalt.

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa 200
210
Elongation at Break, % 46
6.7
Fatigue Strength, MPa 320
130
Poisson's Ratio 0.28
0.28
Shear Modulus, GPa 78
83
Tensile Strength: Ultimate (UTS), MPa 740
560
Tensile Strength: Yield (Proof), MPa 350
260

Thermal Properties

Latent Heat of Fusion, J/g 290
320
Maximum Temperature: Mechanical, °C 940
1200
Melting Completion (Liquidus), °C 1430
1330
Melting Onset (Solidus), °C 1380
1270
Specific Heat Capacity, J/kg-K 480
470
Thermal Conductivity, W/m-K 15
8.5
Thermal Expansion, µm/m-K 17
14

Otherwise Unclassified Properties

Base Metal Price, % relative 17
100
Density, g/cm3 7.7
8.1
Embodied Carbon, kg CO2/kg material 3.6
6.2
Embodied Energy, MJ/kg 51
84
Embodied Water, L/kg 150
440

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 280
31
Resilience: Unit (Modulus of Resilience), kJ/m3 300
160
Stiffness to Weight: Axial, points 14
15
Stiffness to Weight: Bending, points 25
24
Strength to Weight: Axial, points 27
19
Strength to Weight: Bending, points 23
19
Thermal Diffusivity, mm2/s 4.0
2.2
Thermal Shock Resistance, points 16
14

Alloy Composition

Carbon (C), % 0 to 0.080
0.050 to 0.25
Chromium (Cr), % 17.5 to 19.5
27 to 30
Cobalt (Co), % 0
48 to 52
Iron (Fe), % 63 to 74.3
9.7 to 24.5
Manganese (Mn), % 3.5 to 6.5
0 to 1.5
Molybdenum (Mo), % 0.5 to 2.0
0 to 0.5
Nickel (Ni), % 4.0 to 6.5
0 to 4.0
Niobium (Nb), % 0.1 to 1.0
0 to 0.5
Nitrogen (N), % 0.080 to 0.3
0
Phosphorus (P), % 0 to 0.060
0 to 0.040
Silicon (Si), % 0 to 1.0
0.5 to 1.5
Sulfur (S), % 0 to 0.030
0 to 0.030