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AISI 321 Stainless Steel vs. ASTM A387 Grade 9 Steel

Both AISI 321 stainless steel and ASTM A387 grade 9 steel are iron alloys. They have 80% of their average alloy composition in common. There are 32 material properties with values for both materials. Properties with values for just one material (1, in this case) are not shown.

For each property being compared, the top bar is AISI 321 stainless steel and the bottom bar is ASTM A387 grade 9 steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 170 to 210
150 to 180
Elastic (Young's, Tensile) Modulus, GPa 200
190
Elongation at Break, % 34 to 50
20 to 21
Fatigue Strength, MPa 220 to 270
160 to 240
Poisson's Ratio 0.28
0.28
Shear Modulus, GPa 77
75
Shear Strength, MPa 420 to 460
310 to 380
Tensile Strength: Ultimate (UTS), MPa 590 to 690
500 to 600
Tensile Strength: Yield (Proof), MPa 220 to 350
230 to 350

Thermal Properties

Latent Heat of Fusion, J/g 290
270
Maximum Temperature: Mechanical, °C 870
600
Melting Completion (Liquidus), °C 1430
1460
Melting Onset (Solidus), °C 1400
1410
Specific Heat Capacity, J/kg-K 480
470
Thermal Conductivity, W/m-K 16
26
Thermal Expansion, µm/m-K 17
13

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 2.4
9.0
Electrical Conductivity: Equal Weight (Specific), % IACS 2.7
10

Otherwise Unclassified Properties

Base Metal Price, % relative 16
6.5
Density, g/cm3 7.8
7.8
Embodied Carbon, kg CO2/kg material 3.2
2.1
Embodied Energy, MJ/kg 45
28
Embodied Water, L/kg 140
87

Common Calculations

PREN (Pitting Resistance) 19
12
Resilience: Ultimate (Unit Rupture Work), MJ/m3 190 to 230
83 to 110
Resilience: Unit (Modulus of Resilience), kJ/m3 130 to 310
140 to 310
Stiffness to Weight: Axial, points 14
14
Stiffness to Weight: Bending, points 25
25
Strength to Weight: Axial, points 21 to 25
18 to 21
Strength to Weight: Bending, points 20 to 22
18 to 20
Thermal Diffusivity, mm2/s 4.1
6.9
Thermal Shock Resistance, points 13 to 15
14 to 17

Alloy Composition

Carbon (C), % 0 to 0.080
0 to 0.15
Chromium (Cr), % 17 to 19
8.0 to 10
Iron (Fe), % 65.3 to 74
87.1 to 90.8
Manganese (Mn), % 0 to 2.0
0.3 to 0.6
Molybdenum (Mo), % 0
0.9 to 1.1
Nickel (Ni), % 9.0 to 12
0
Nitrogen (N), % 0 to 0.1
0
Phosphorus (P), % 0 to 0.045
0 to 0.025
Silicon (Si), % 0 to 0.75
0 to 1.0
Sulfur (S), % 0 to 0.030
0 to 0.025
Titanium (Ti), % 0 to 0.7
0
Vanadium (V), % 0
0 to 0.040