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SAE-AISI 8645 Steel vs. AISI 321 Stainless Steel

Both SAE-AISI 8645 steel and AISI 321 stainless steel are iron alloys. They have 72% of their average alloy composition in common. There are 31 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown.

For each property being compared, the top bar is SAE-AISI 8645 steel and the bottom bar is AISI 321 stainless steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 180 to 200
170 to 210
Elastic (Young's, Tensile) Modulus, GPa 190
200
Elongation at Break, % 12 to 23
34 to 50
Fatigue Strength, MPa 280 to 350
220 to 270
Poisson's Ratio 0.29
0.28
Shear Modulus, GPa 73
77
Shear Strength, MPa 380 to 400
420 to 460
Tensile Strength: Ultimate (UTS), MPa 600 to 670
590 to 690
Tensile Strength: Yield (Proof), MPa 390 to 560
220 to 350

Thermal Properties

Latent Heat of Fusion, J/g 250
290
Maximum Temperature: Mechanical, °C 410
870
Melting Completion (Liquidus), °C 1460
1430
Melting Onset (Solidus), °C 1420
1400
Specific Heat Capacity, J/kg-K 470
480
Thermal Conductivity, W/m-K 39
16
Thermal Expansion, µm/m-K 13
17

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 7.3
2.4
Electrical Conductivity: Equal Weight (Specific), % IACS 8.4
2.7

Otherwise Unclassified Properties

Base Metal Price, % relative 2.6
16
Density, g/cm3 7.8
7.8
Embodied Carbon, kg CO2/kg material 1.5
3.2
Embodied Energy, MJ/kg 20
45
Embodied Water, L/kg 50
140

Common Calculations

Resilience: Ultimate (Unit Rupture Work), MJ/m3 77 to 120
190 to 230
Resilience: Unit (Modulus of Resilience), kJ/m3 420 to 840
130 to 310
Stiffness to Weight: Axial, points 13
14
Stiffness to Weight: Bending, points 24
25
Strength to Weight: Axial, points 21 to 24
21 to 25
Strength to Weight: Bending, points 20 to 22
20 to 22
Thermal Diffusivity, mm2/s 10
4.1
Thermal Shock Resistance, points 18 to 20
13 to 15

Alloy Composition

Carbon (C), % 0.43 to 0.48
0 to 0.080
Chromium (Cr), % 0.4 to 0.6
17 to 19
Iron (Fe), % 96.5 to 97.7
65.3 to 74
Manganese (Mn), % 0.75 to 1.0
0 to 2.0
Molybdenum (Mo), % 0.15 to 0.25
0
Nickel (Ni), % 0.4 to 0.7
9.0 to 12
Nitrogen (N), % 0
0 to 0.1
Phosphorus (P), % 0 to 0.035
0 to 0.045
Silicon (Si), % 0.15 to 0.35
0 to 0.75
Sulfur (S), % 0 to 0.040
0 to 0.030
Titanium (Ti), % 0
0 to 0.7

Comparable Variants