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AISI 418 Stainless Steel vs. SAE-AISI 8740 Steel

Both AISI 418 stainless steel and SAE-AISI 8740 steel are iron alloys. They have 83% of their average alloy composition in common. There are 31 material properties with values for both materials. Properties with values for just one material (3, in this case) are not shown.

For each property being compared, the top bar is AISI 418 stainless steel and the bottom bar is SAE-AISI 8740 steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 330
170 to 200
Elastic (Young's, Tensile) Modulus, GPa 200
190
Elongation at Break, % 17
11 to 23
Fatigue Strength, MPa 520
270 to 350
Poisson's Ratio 0.28
0.29
Shear Modulus, GPa 77
73
Shear Strength, MPa 680
370 to 400
Tensile Strength: Ultimate (UTS), MPa 1100
580 to 670
Tensile Strength: Yield (Proof), MPa 850
380 to 570

Thermal Properties

Latent Heat of Fusion, J/g 270
250
Maximum Temperature: Mechanical, °C 770
410
Melting Completion (Liquidus), °C 1500
1460
Melting Onset (Solidus), °C 1460
1420
Specific Heat Capacity, J/kg-K 470
470
Thermal Conductivity, W/m-K 25
39
Thermal Expansion, µm/m-K 10
13

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 2.8
7.3
Electrical Conductivity: Equal Weight (Specific), % IACS 3.1
8.4

Otherwise Unclassified Properties

Base Metal Price, % relative 15
2.6
Density, g/cm3 8.0
7.8
Embodied Carbon, kg CO2/kg material 2.9
1.5
Embodied Energy, MJ/kg 41
20
Embodied Water, L/kg 110
50

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 170
71 to 120
Resilience: Unit (Modulus of Resilience), kJ/m3 1830
390 to 850
Stiffness to Weight: Axial, points 14
13
Stiffness to Weight: Bending, points 24
24
Strength to Weight: Axial, points 38
20 to 24
Strength to Weight: Bending, points 29
20 to 22
Thermal Diffusivity, mm2/s 6.7
10
Thermal Shock Resistance, points 40
17 to 20

Alloy Composition

Carbon (C), % 0.15 to 0.2
0.38 to 0.43
Chromium (Cr), % 12 to 14
0.4 to 0.6
Iron (Fe), % 78.5 to 83.6
96.5 to 97.7
Manganese (Mn), % 0 to 0.5
0.75 to 1.0
Molybdenum (Mo), % 0 to 0.5
0.2 to 0.3
Nickel (Ni), % 1.8 to 2.2
0.4 to 0.7
Phosphorus (P), % 0 to 0.040
0 to 0.035
Silicon (Si), % 0 to 0.5
0.15 to 0.35
Sulfur (S), % 0 to 0.030
0 to 0.040
Tungsten (W), % 2.5 to 3.5
0