SAE-AISI P4 Steel vs. S21800 Stainless Steel

Both SAE-AISI P4 steel and S21800 stainless 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 SAE-AISI P4 steel and the bottom bar is S21800 stainless steel.

SAE-AISI P4 (T51604) Low-Carbon Mould Steel UNS S21800 (Alloy 218) Stainless Steel

Metric UnitsUS Customary Units

Mechanical Properties

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

Poisson's Ratio		0.29
Poisson's Ratio		0.28

Shear Modulus, GPa		74
Shear Modulus, GPa		75

Tensile Strength: Ultimate (UTS), MPa		390 to 1980
Tensile Strength: Ultimate (UTS), MPa		740

Thermal Properties

Latent Heat of Fusion, J/g		260
Latent Heat of Fusion, J/g		340

Melting Completion (Liquidus), °C		1460
Melting Completion (Liquidus), °C		1360

Melting Onset (Solidus), °C		1420
Melting Onset (Solidus), °C		1310

Specific Heat Capacity, J/kg-K		470
Specific Heat Capacity, J/kg-K		500

Thermal Expansion, µm/m-K		12
Thermal Expansion, µm/m-K		16

Otherwise Unclassified Properties

Base Metal Price, % relative		4.4
Base Metal Price, % relative		15

Density, g/cm³		7.8
Density, g/cm³		7.5

Embodied Carbon, kg CO₂/kg material		1.8
Embodied Carbon, kg CO₂/kg material		3.1

Embodied Energy, MJ/kg		23
Embodied Energy, MJ/kg		45

Embodied Water, L/kg		68
Embodied Water, L/kg		150

Common Calculations

PREN (Pitting Resistance)		7.0
PREN (Pitting Resistance)		19

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

Stiffness to Weight: Bending, points		24
Stiffness to Weight: Bending, points		26

Strength to Weight: Axial, points		14 to 70
Strength to Weight: Axial, points		27

Strength to Weight: Bending, points		15 to 45
Strength to Weight: Bending, points		24

Thermal Shock Resistance, points		13 to 64
Thermal Shock Resistance, points		17

Alloy Composition

Carbon (C), %		0 to 0.12
Carbon (C), %		0 to 0.1

Chromium (Cr), %		4.0 to 5.3
Chromium (Cr), %		16 to 18

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

Iron (Fe), %		92.3 to 95.3
Iron (Fe), %		59.1 to 65.4

Manganese (Mn), %		0.2 to 0.6
Manganese (Mn), %		7.0 to 9.0

Molybdenum (Mo), %		0.4 to 1.0
Molybdenum (Mo), %		0

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

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

Phosphorus (P), %		0 to 0.030
Phosphorus (P), %		0 to 0.060

Silicon (Si), %		0.1 to 0.4
Silicon (Si), %		3.5 to 4.5

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