S21800 Stainless Steel vs. R05240 Alloy

S21800 stainless steel belongs to the iron alloys classification, while R05240 alloy belongs to the otherwise unclassified metals. There are 18 material properties with values for both materials. Properties with values for just one material (13, in this case) are not shown.

For each property being compared, the top bar is S21800 stainless steel and the bottom bar is R05240 alloy.

UNS S21800 (Alloy 218) Stainless Steel UNS R05240 Tantalum-Niobium Alloy

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		190
Elastic (Young's, Tensile) Modulus, GPa		150

Elongation at Break, %		40
Elongation at Break, %		25

Poisson's Ratio		0.28
Poisson's Ratio		0.36

Shear Modulus, GPa		75
Shear Modulus, GPa		57

Tensile Strength: Ultimate (UTS), MPa		740
Tensile Strength: Ultimate (UTS), MPa		270

Tensile Strength: Yield (Proof), MPa		390
Tensile Strength: Yield (Proof), MPa		170

Thermal Properties

Latent Heat of Fusion, J/g		340
Latent Heat of Fusion, J/g		210

Specific Heat Capacity, J/kg-K		500
Specific Heat Capacity, J/kg-K		190

Thermal Expansion, µm/m-K		16
Thermal Expansion, µm/m-K		6.8

Otherwise Unclassified Properties

Density, g/cm³		7.5
Density, g/cm³		14

Embodied Water, L/kg		150
Embodied Water, L/kg		460

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m³		250
Resilience: Ultimate (Unit Rupture Work), MJ/m³		59

Resilience: Unit (Modulus of Resilience), kJ/m³		390
Resilience: Unit (Modulus of Resilience), kJ/m³		90

Stiffness to Weight: Axial, points		14
Stiffness to Weight: Axial, points		6.3

Stiffness to Weight: Bending, points		26
Stiffness to Weight: Bending, points		13

Strength to Weight: Axial, points		27
Strength to Weight: Axial, points		5.4

Strength to Weight: Bending, points		24
Strength to Weight: Bending, points		6.8

Thermal Shock Resistance, points		17
Thermal Shock Resistance, points		18

Alloy Composition

Carbon (C), %		0 to 0.1
Carbon (C), %		0 to 0.010

Chromium (Cr), %		16 to 18
Chromium (Cr), %		0

Hydrogen (H), %		0
Hydrogen (H), %		0 to 0.0015

Iron (Fe), %		59.1 to 65.4
Iron (Fe), %		0 to 0.010

Manganese (Mn), %		7.0 to 9.0
Manganese (Mn), %		0

Molybdenum (Mo), %		0
Molybdenum (Mo), %		0 to 0.020

Nickel (Ni), %		8.0 to 9.0
Nickel (Ni), %		0 to 0.010

Niobium (Nb), %		0
Niobium (Nb), %		35 to 42

Nitrogen (N), %		0.080 to 0.18
Nitrogen (N), %		0 to 0.010

Oxygen (O), %		0
Oxygen (O), %		0 to 0.020

Phosphorus (P), %		0 to 0.060
Phosphorus (P), %		0

Silicon (Si), %		3.5 to 4.5
Silicon (Si), %		0 to 0.0050

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

Tantalum (Ta), %		0
Tantalum (Ta), %		57.9 to 65

Titanium (Ti), %		0
Titanium (Ti), %		0 to 0.010

Tungsten (W), %		0
Tungsten (W), %		0 to 0.050