ASTM A372 Grade J Steel vs. AZ91B Magnesium
ASTM A372 grade J steel belongs to the iron alloys classification, while AZ91B magnesium belongs to the magnesium alloys. There are 31 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown. Please note that the two materials have significantly dissimilar densities. This means that additional care is required when interpreting the data, because some material properties are based on units of mass, while others are based on units of area or volume.
For each property being compared, the top bar is ASTM A372 grade J steel and the bottom bar is AZ91B magnesium.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 200 to 310 | |
| 63 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 46 |
| Elongation at Break, % | 17 to 22 | |
| 5.0 |
| Fatigue Strength, MPa | 310 to 570 | |
| 79 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 18 |
| Shear Strength, MPa | 410 to 630 | |
| 140 |
| Tensile Strength: Ultimate (UTS), MPa | 650 to 1020 | |
| 240 |
| Tensile Strength: Yield (Proof), MPa | 430 to 850 | |
| 160 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 360 |
| Maximum Temperature: Mechanical, °C | 420 | |
| 130 |
| Melting Completion (Liquidus), °C | 1460 | |
| 600 |
| Melting Onset (Solidus), °C | 1420 | |
| 470 |
| Specific Heat Capacity, J/kg-K | 470 | |
| 990 |
| Thermal Conductivity, W/m-K | 44 | |
| 73 |
| Thermal Expansion, µm/m-K | 13 | |
| 26 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.3 | |
| 11 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.4 | |
| 58 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.4 | |
| 12 |
| Density, g/cm3 | 7.8 | |
| 1.7 |
| Embodied Carbon, kg CO2/kg material | 1.5 | |
| 22 |
| Embodied Energy, MJ/kg | 20 | |
| 160 |
| Embodied Water, L/kg | 51 | |
| 990 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 130 to 170 | |
| 11 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 500 to 1930 | |
| 280 |
| Stiffness to Weight: Axial, points | 13 | |
| 15 |
| Stiffness to Weight: Bending, points | 24 | |
| 69 |
| Strength to Weight: Axial, points | 23 to 36 | |
| 38 |
| Strength to Weight: Bending, points | 21 to 29 | |
| 49 |
| Thermal Diffusivity, mm2/s | 12 | |
| 42 |
| Thermal Shock Resistance, points | 19 to 30 | |
| 14 |
Alloy Composition
| Aluminum (Al), % | 0 | |
| 8.3 to 9.7 |
| Carbon (C), % | 0.35 to 0.5 | |
| 0 |
| Chromium (Cr), % | 0.8 to 1.2 | |
| 0 |
| Copper (Cu), % | 0 | |
| 0 to 0.35 |
| Iron (Fe), % | 96.7 to 97.8 | |
| 0 |
| Magnesium (Mg), % | 0 | |
| 87.9 to 91.2 |
| Manganese (Mn), % | 0.75 to 1.1 | |
| 0.13 to 0.5 |
| Molybdenum (Mo), % | 0.15 to 0.25 | |
| 0 |
| Nickel (Ni), % | 0 | |
| 0 to 0.030 |
| Phosphorus (P), % | 0 to 0.015 | |
| 0 |
| Silicon (Si), % | 0.15 to 0.35 | |
| 0 to 0.5 |
| Sulfur (S), % | 0 to 0.010 | |
| 0 |
| Zinc (Zn), % | 0 | |
| 0.35 to 1.0 |