S21603 Stainless Steel vs. SAE-AISI A4 Steel

Both S21603 stainless steel and SAE-AISI A4 steel are iron alloys. They have 68% of their average alloy composition in common. There are 20 material properties with values for both materials. Properties with values for just one material (15, in this case) are not shown.

For each property being compared, the top bar is S21603 stainless steel and the bottom bar is SAE-AISI A4 steel.

UNS S21603 (XM-18) Stainless Steel SAE-AISI A4 (T30104) Air-Hardening Steel

Metric UnitsUS Customary Units

Mechanical Properties

Elastic (Young's, Tensile) Modulus, GPa		200
Elastic (Young's, Tensile) Modulus, GPa		190

Poisson's Ratio		0.28
Poisson's Ratio		0.29

Shear Modulus, GPa		79
Shear Modulus, GPa		73

Tensile Strength: Ultimate (UTS), MPa		690
Tensile Strength: Ultimate (UTS), MPa		710 to 2050

Thermal Properties

Latent Heat of Fusion, J/g		290
Latent Heat of Fusion, J/g		250

Melting Completion (Liquidus), °C		1420
Melting Completion (Liquidus), °C		1450

Melting Onset (Solidus), °C		1380
Melting Onset (Solidus), °C		1410

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

Thermal Expansion, µm/m-K		17
Thermal Expansion, µm/m-K		12

Otherwise Unclassified Properties

Base Metal Price, % relative		17
Base Metal Price, % relative		3.9

Density, g/cm³		7.7
Density, g/cm³		7.8

Embodied Carbon, kg CO₂/kg material		3.6
Embodied Carbon, kg CO₂/kg material		1.8

Embodied Energy, MJ/kg		50
Embodied Energy, MJ/kg		24

Embodied Water, L/kg		160
Embodied Water, L/kg		59

Common Calculations

PREN (Pitting Resistance)		34
PREN (Pitting Resistance)		5.3

Stiffness to Weight: Axial, points		14
Stiffness to Weight: Axial, points		13

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

Strength to Weight: Axial, points		25
Strength to Weight: Axial, points		25 to 73

Strength to Weight: Bending, points		22
Strength to Weight: Bending, points		23 to 46

Thermal Shock Resistance, points		15
Thermal Shock Resistance, points		23 to 67

Alloy Composition

Carbon (C), %		0 to 0.030
Carbon (C), %		1.0 to 1.1

Chromium (Cr), %		17.5 to 22
Chromium (Cr), %		0.9 to 2.2

Copper (Cu), %		0
Copper (Cu), %		0 to 0.25

Iron (Fe), %		57.6 to 67.8
Iron (Fe), %		92 to 95.5

Manganese (Mn), %		7.5 to 9.0
Manganese (Mn), %		1.8 to 2.2

Molybdenum (Mo), %		2.0 to 3.0
Molybdenum (Mo), %		0.9 to 1.4

Nickel (Ni), %		5.0 to 7.0
Nickel (Ni), %		0 to 0.3

Nitrogen (N), %		0.25 to 0.5
Nitrogen (N), %		0

Phosphorus (P), %		0 to 0.045
Phosphorus (P), %		0 to 0.030

Silicon (Si), %		0 to 0.75
Silicon (Si), %		0 to 0.5

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