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SAE-AISI 4340 Steel vs. S31727 Stainless Steel

Both SAE-AISI 4340 steel and S31727 stainless steel are iron alloys. They have 61% of their average alloy composition in common. There are 27 material properties with values for both materials. Properties with values for just one material (8, in this case) are not shown.

For each property being compared, the top bar is SAE-AISI 4340 steel and the bottom bar is S31727 stainless steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 210 to 360
190
Elastic (Young's, Tensile) Modulus, GPa 190
200
Elongation at Break, % 12 to 22
40
Fatigue Strength, MPa 330 to 740
240
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 73
78
Shear Strength, MPa 430 to 770
430
Tensile Strength: Ultimate (UTS), MPa 690 to 1280
630
Tensile Strength: Yield (Proof), MPa 470 to 1150
270

Thermal Properties

Latent Heat of Fusion, J/g 250
290
Maximum Temperature: Mechanical, °C 430
1010
Melting Completion (Liquidus), °C 1460
1440
Melting Onset (Solidus), °C 1420
1390
Specific Heat Capacity, J/kg-K 470
470
Thermal Expansion, µm/m-K 13
16

Otherwise Unclassified Properties

Base Metal Price, % relative 3.5
24
Density, g/cm3 7.8
8.0
Embodied Carbon, kg CO2/kg material 1.7
4.7
Embodied Energy, MJ/kg 22
64
Embodied Water, L/kg 53
180

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 79 to 170
200
Resilience: Unit (Modulus of Resilience), kJ/m3 590 to 3490
190
Stiffness to Weight: Axial, points 13
14
Stiffness to Weight: Bending, points 24
24
Strength to Weight: Axial, points 24 to 45
22
Strength to Weight: Bending, points 22 to 33
20
Thermal Shock Resistance, points 20 to 38
14

Alloy Composition

Carbon (C), % 0.38 to 0.43
0 to 0.030
Chromium (Cr), % 0.7 to 0.9
17.5 to 19
Copper (Cu), % 0
2.8 to 4.0
Iron (Fe), % 95.1 to 96.3
53.7 to 61.3
Manganese (Mn), % 0.6 to 0.8
0 to 1.0
Molybdenum (Mo), % 0.2 to 0.3
3.8 to 4.5
Nickel (Ni), % 1.7 to 2.0
14.5 to 16.5
Nitrogen (N), % 0
0.15 to 0.21
Phosphorus (P), % 0 to 0.035
0 to 0.030
Silicon (Si), % 0.15 to 0.35
0 to 1.0
Sulfur (S), % 0 to 0.040
0 to 0.030