ASTM A387 Grade 21 Steel vs. AWS BNi-6

ASTM A387 grade 21 steel belongs to the iron alloys classification, while AWS BNi-6 belongs to the nickel alloys. There are 19 material properties with values for both materials. Properties with values for just one material (14, in this case) are not shown.

For each property being compared, the top bar is ASTM A387 grade 21 steel and the bottom bar is AWS BNi-6.

ASTM A387 Grade 21 (K31545) 3Cr-1Mo Steel AWS BNi-6 (N99700) Filler Metal

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		190
Elastic (Young's, Tensile) Modulus, GPa		160

Poisson's Ratio		0.29
Poisson's Ratio		0.31

Shear Modulus, GPa		74
Shear Modulus, GPa		62

Tensile Strength: Ultimate (UTS), MPa		500 to 590
Tensile Strength: Ultimate (UTS), MPa		450

Thermal Properties

Latent Heat of Fusion, J/g		260
Latent Heat of Fusion, J/g		260

Melting Completion (Liquidus), °C		1470
Melting Completion (Liquidus), °C		880

Melting Onset (Solidus), °C		1430
Melting Onset (Solidus), °C		880

Specific Heat Capacity, J/kg-K		470
Specific Heat Capacity, J/kg-K		480

Thermal Expansion, µm/m-K		13
Thermal Expansion, µm/m-K		9.8

Otherwise Unclassified Properties

Base Metal Price, % relative		4.1
Base Metal Price, % relative		55

Density, g/cm³		7.9
Density, g/cm³		8.2

Embodied Carbon, kg CO₂/kg material		1.8
Embodied Carbon, kg CO₂/kg material		9.4

Embodied Energy, MJ/kg		23
Embodied Energy, MJ/kg		130

Embodied Water, L/kg		62
Embodied Water, L/kg		210

Common Calculations

Stiffness to Weight: Axial, points		13
Stiffness to Weight: Axial, points		11

Stiffness to Weight: Bending, points		24
Stiffness to Weight: Bending, points		22

Strength to Weight: Axial, points		18 to 21
Strength to Weight: Axial, points		15

Strength to Weight: Bending, points		18 to 20
Strength to Weight: Bending, points		16

Thermal Shock Resistance, points		14 to 17
Thermal Shock Resistance, points		20

Alloy Composition

Aluminum (Al), %		0
Aluminum (Al), %		0 to 0.050

Carbon (C), %		0.050 to 0.15
Carbon (C), %		0 to 0.060

Chromium (Cr), %		2.8 to 3.3
Chromium (Cr), %		0

Cobalt (Co), %		0
Cobalt (Co), %		0 to 0.1

Iron (Fe), %		94.4 to 96
Iron (Fe), %		0

Manganese (Mn), %		0.3 to 0.6
Manganese (Mn), %		0

Molybdenum (Mo), %		0.9 to 1.1
Molybdenum (Mo), %		0

Nickel (Ni), %		0
Nickel (Ni), %		87.2 to 90

Phosphorus (P), %		0 to 0.025
Phosphorus (P), %		10 to 12

Selenium (Se), %		0
Selenium (Se), %		0 to 0.0050

Silicon (Si), %		0 to 0.5
Silicon (Si), %		0

Sulfur (S), %		0 to 0.025
Sulfur (S), %		0 to 0.020

Titanium (Ti), %		0
Titanium (Ti), %		0 to 0.050

Zirconium (Zr), %		0
Zirconium (Zr), %		0 to 0.050

Residuals, %		0
Residuals, %		0 to 0.5