SAE-AISI 81B45 Steel vs. SAE-AISI 4718 Steel
Both SAE-AISI 81B45 steel and SAE-AISI 4718 steel are iron alloys. They have a very high 99% of their average alloy composition in common.
For each property being compared, the top bar is SAE-AISI 81B45 steel and the bottom bar is SAE-AISI 4718 steel.
Metric UnitsUS Customary Units
Mechanical Properties
Brinell Hardness | 160 to 200 | |
150 |
Elastic (Young's, Tensile) Modulus, GPa | 190 | |
190 |
Elongation at Break, % | 12 to 24 | |
24 |
Fatigue Strength, MPa | 250 to 350 | |
270 |
Poisson's Ratio | 0.29 | |
0.29 |
Shear Modulus, GPa | 73 | |
73 |
Shear Strength, MPa | 340 to 400 | |
330 |
Tensile Strength: Ultimate (UTS), MPa | 540 to 670 | |
510 |
Tensile Strength: Yield (Proof), MPa | 350 to 560 | |
370 |
Thermal Properties
Latent Heat of Fusion, J/g | 250 | |
250 |
Maximum Temperature: Mechanical, °C | 410 | |
420 |
Melting Completion (Liquidus), °C | 1460 | |
1460 |
Melting Onset (Solidus), °C | 1420 | |
1420 |
Specific Heat Capacity, J/kg-K | 470 | |
470 |
Thermal Conductivity, W/m-K | 40 | |
39 |
Thermal Expansion, µm/m-K | 12 | |
11 |
Electrical Properties
Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
7.3 |
Electrical Conductivity: Equal Weight (Specific), % IACS | 8.3 | |
8.4 |
Otherwise Unclassified Properties
Base Metal Price, % relative | 2.3 | |
3.0 |
Density, g/cm3 | 7.8 | |
7.9 |
Embodied Carbon, kg CO2/kg material | 1.5 | |
1.6 |
Embodied Energy, MJ/kg | 20 | |
21 |
Embodied Water, L/kg | 49 | |
51 |
Common Calculations
Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 77 to 110 | |
110 |
Resilience: Unit (Modulus of Resilience), kJ/m3 | 320 to 840 | |
360 |
Stiffness to Weight: Axial, points | 13 | |
13 |
Stiffness to Weight: Bending, points | 24 | |
24 |
Strength to Weight: Axial, points | 19 to 24 | |
18 |
Strength to Weight: Bending, points | 19 to 22 | |
18 |
Thermal Diffusivity, mm2/s | 11 | |
10 |
Thermal Shock Resistance, points | 17 to 21 | |
17 |
Alloy Composition
Boron (B), % | 0.00050 to 0.0030 | |
0 |
Carbon (C), % | 0.43 to 0.48 | |
0.16 to 0.21 |
Chromium (Cr), % | 0.35 to 0.55 | |
0.35 to 0.55 |
Iron (Fe), % | 97 to 98 | |
96.3 to 97.4 |
Manganese (Mn), % | 0.75 to 1.0 | |
0.7 to 0.9 |
Molybdenum (Mo), % | 0.080 to 0.15 | |
0.3 to 0.4 |
Nickel (Ni), % | 0.2 to 0.4 | |
0.9 to 1.2 |
Phosphorus (P), % | 0 to 0.035 | |
0 to 0.035 |
Silicon (Si), % | 0.15 to 0.35 | |
0.15 to 0.35 |
Sulfur (S), % | 0 to 0.040 | |
0 to 0.040 |