MakeItFrom.com
Menu (ESC)

ASTM A387 Grade 91 Class 2 vs. ASTM A387 Grade 21 Steel

Both ASTM A387 grade 91 class 2 and ASTM A387 grade 21 steel are iron alloys. They have a moderately high 94% of their average alloy composition in common.

For each property being compared, the top bar is ASTM A387 grade 91 class 2 and the bottom bar is ASTM A387 grade 21 steel.

Metric UnitsUS Customary Units

Mechanical Properties

Brinell Hardness 200
150 to 180
Elastic (Young's, Tensile) Modulus, GPa 190
190
Elongation at Break, % 20
21
Fatigue Strength, MPa 330
160 to 250
Poisson's Ratio 0.28
0.29
Shear Modulus, GPa 75
74
Shear Strength, MPa 420
310 to 370
Tensile Strength: Ultimate (UTS), MPa 670
500 to 590
Tensile Strength: Yield (Proof), MPa 470
230 to 350

Thermal Properties

Latent Heat of Fusion, J/g 270
260
Maximum Temperature: Mechanical, °C 600
480
Melting Completion (Liquidus), °C 1460
1470
Melting Onset (Solidus), °C 1420
1430
Specific Heat Capacity, J/kg-K 470
470
Thermal Conductivity, W/m-K 26
41
Thermal Expansion, µm/m-K 13
13

Electrical Properties

Electrical Conductivity: Equal Volume, % IACS 8.9
7.6
Electrical Conductivity: Equal Weight (Specific), % IACS 10
8.8

Otherwise Unclassified Properties

Base Metal Price, % relative 7.0
4.1
Density, g/cm3 7.8
7.9
Embodied Carbon, kg CO2/kg material 2.6
1.8
Embodied Energy, MJ/kg 37
23
Embodied Water, L/kg 88
62

Common Calculations

PREN (Pitting Resistance) 13
6.4
Resilience: Ultimate (Unit Rupture Work), MJ/m3 120
84 to 110
Resilience: Unit (Modulus of Resilience), kJ/m3 580
140 to 320
Stiffness to Weight: Axial, points 14
13
Stiffness to Weight: Bending, points 25
24
Strength to Weight: Axial, points 24
18 to 21
Strength to Weight: Bending, points 22
18 to 20
Thermal Diffusivity, mm2/s 6.9
11
Thermal Shock Resistance, points 19
14 to 17

Alloy Composition

Aluminum (Al), % 0 to 0.020
0
Carbon (C), % 0.080 to 0.12
0.050 to 0.15
Chromium (Cr), % 8.0 to 9.5
2.8 to 3.3
Iron (Fe), % 87.3 to 90.3
94.4 to 96
Manganese (Mn), % 0.3 to 0.6
0.3 to 0.6
Molybdenum (Mo), % 0.85 to 1.1
0.9 to 1.1
Nickel (Ni), % 0 to 0.4
0
Niobium (Nb), % 0.060 to 0.1
0
Nitrogen (N), % 0.030 to 0.070
0
Phosphorus (P), % 0 to 0.020
0 to 0.025
Silicon (Si), % 0.2 to 0.5
0 to 0.5
Sulfur (S), % 0 to 0.010
0 to 0.025
Titanium (Ti), % 0 to 0.010
0
Vanadium (V), % 0.18 to 0.25
0
Zirconium (Zr), % 0 to 0.010
0