R31538 Cobalt vs. AWS E312

R31538 cobalt belongs to the cobalt alloys classification, while AWS E312 belongs to the iron alloys. They have a modest 30% of their average alloy composition in common, which, by itself, doesn't mean much. There are 19 material properties with values for both materials. Properties with values for just one material (12, in this case) are not shown.

For each property being compared, the top bar is R31538 cobalt and the bottom bar is AWS E312.

High Carbon Co-28Cr-6Mo Alloy (ASTM F1537 Alloy 2, ISO 5832-12 Alloy 2, R31538)AWS E312 (W31310) Weld Metal

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		220
Elastic (Young's, Tensile) Modulus, GPa		200

Elongation at Break, %		13 to 23
Elongation at Break, %		25

Poisson's Ratio		0.29
Poisson's Ratio		0.27

Shear Modulus, GPa		86
Shear Modulus, GPa		80

Tensile Strength: Ultimate (UTS), MPa		1020 to 1360
Tensile Strength: Ultimate (UTS), MPa		740

Thermal Properties

Latent Heat of Fusion, J/g		320
Latent Heat of Fusion, J/g		310

Melting Completion (Liquidus), °C		1360
Melting Completion (Liquidus), °C		1410

Melting Onset (Solidus), °C		1290
Melting Onset (Solidus), °C		1360

Specific Heat Capacity, J/kg-K		450
Specific Heat Capacity, J/kg-K		480

Thermal Expansion, µm/m-K		13
Thermal Expansion, µm/m-K		15

Otherwise Unclassified Properties

Density, g/cm³		8.4
Density, g/cm³		7.7

Embodied Carbon, kg CO₂/kg material		8.1
Embodied Carbon, kg CO₂/kg material		3.6

Embodied Energy, MJ/kg		110
Embodied Energy, MJ/kg		52

Embodied Water, L/kg		530
Embodied Water, L/kg		200

Common Calculations

Stiffness to Weight: Axial, points		15
Stiffness to Weight: Axial, points		15

Stiffness to Weight: Bending, points		24
Stiffness to Weight: Bending, points		25

Strength to Weight: Axial, points		34 to 45
Strength to Weight: Axial, points		27

Strength to Weight: Bending, points		27 to 32
Strength to Weight: Bending, points		24

Thermal Shock Resistance, points		25 to 33
Thermal Shock Resistance, points		18

Alloy Composition

Carbon (C), %		0.15 to 0.35
Carbon (C), %		0 to 0.15

Chromium (Cr), %		26 to 30
Chromium (Cr), %		28 to 32

Cobalt (Co), %		58.7 to 68.9
Cobalt (Co), %		0

Copper (Cu), %		0
Copper (Cu), %		0 to 0.75

Iron (Fe), %		0 to 0.75
Iron (Fe), %		52.3 to 63.5

Manganese (Mn), %		0 to 1.0
Manganese (Mn), %		0.5 to 2.5

Molybdenum (Mo), %		5.0 to 7.0
Molybdenum (Mo), %		0 to 0.75

Nickel (Ni), %		0 to 1.0
Nickel (Ni), %		8.0 to 10.5

Nitrogen (N), %		0 to 0.25
Nitrogen (N), %		0

Phosphorus (P), %		0
Phosphorus (P), %		0 to 0.040

Silicon (Si), %		0 to 1.0
Silicon (Si), %		0 to 1.0

Sulfur (S), %		0
Sulfur (S), %		0 to 0.030