ASTM A372 Grade M Class 100 vs. ASTM A372 Grade M Class 85
Both ASTM A372 grade M class 100 and ASTM A372 grade M class 85 are variants of the same material. They share alloy composition and many physical properties, but develop different mechanical properties as a result of different processing.
For each property being compared, the top bar is ASTM A372 grade M class 100 and the bottom bar is ASTM A372 grade M class 85.
Metric UnitsUS Customary Units
Mechanical Properties
Brinell Hardness | 280 | |
240 |
Elastic (Young's, Tensile) Modulus, GPa | 190 | |
190 |
Elongation at Break, % | 18 | |
21 |
Fatigue Strength, MPa | 520 | |
450 |
Poisson's Ratio | 0.29 | |
0.29 |
Shear Modulus, GPa | 73 | |
73 |
Shear Strength, MPa | 570 | |
510 |
Tensile Strength: Ultimate (UTS), MPa | 910 | |
810 |
Tensile Strength: Yield (Proof), MPa | 770 | |
660 |
Thermal Properties
Latent Heat of Fusion, J/g | 250 | |
250 |
Maximum Temperature: Mechanical, °C | 450 | |
450 |
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 | 46 | |
46 |
Thermal Expansion, µm/m-K | 13 | |
13 |
Electrical Properties
Electrical Conductivity: Equal Volume, % IACS | 8.0 | |
8.0 |
Electrical Conductivity: Equal Weight (Specific), % IACS | 9.1 | |
9.1 |
Otherwise Unclassified Properties
Base Metal Price, % relative | 5.0 | |
5.0 |
Density, g/cm3 | 7.9 | |
7.9 |
Embodied Carbon, kg CO2/kg material | 2.0 | |
2.0 |
Embodied Energy, MJ/kg | 27 | |
27 |
Embodied Water, L/kg | 61 | |
61 |
Common Calculations
PREN (Pitting Resistance) | 3.4 | |
3.4 |
Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 160 | |
160 |
Resilience: Unit (Modulus of Resilience), kJ/m3 | 1580 | |
1140 |
Stiffness to Weight: Axial, points | 13 | |
13 |
Stiffness to Weight: Bending, points | 24 | |
24 |
Strength to Weight: Axial, points | 32 | |
29 |
Strength to Weight: Bending, points | 27 | |
24 |
Thermal Diffusivity, mm2/s | 12 | |
12 |
Thermal Shock Resistance, points | 27 | |
24 |
Alloy Composition
Carbon (C), % | 0 to 0.23 | |
0 to 0.23 |
Chromium (Cr), % | 1.5 to 2.0 | |
1.5 to 2.0 |
Iron (Fe), % | 92.5 to 95.1 | |
92.5 to 95.1 |
Manganese (Mn), % | 0.2 to 0.4 | |
0.2 to 0.4 |
Molybdenum (Mo), % | 0.4 to 0.6 | |
0.4 to 0.6 |
Nickel (Ni), % | 2.8 to 3.9 | |
2.8 to 3.9 |
Phosphorus (P), % | 0 to 0.015 | |
0 to 0.015 |
Silicon (Si), % | 0 to 0.3 | |
0 to 0.3 |
Sulfur (S), % | 0 to 0.010 | |
0 to 0.010 |
Vanadium (V), % | 0 to 0.080 | |
0 to 0.080 |