ASTM A572 Grade 55 vs. ASTM A572 Grade 65
Both ASTM A572 grade 55 and ASTM A572 grade 65 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 A572 grade 55 and the bottom bar is ASTM A572 grade 65.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 | |
| 190 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 190 |
| Elongation at Break, % | 21 | |
| 18 |
| Fatigue Strength, MPa | 300 | |
| 340 |
| Poisson's Ratio | 0.29 | |
| 0.29 |
| Shear Modulus, GPa | 73 | |
| 73 |
| Shear Strength, MPa | 340 | |
| 380 |
| Tensile Strength: Ultimate (UTS), MPa | 550 | |
| 620 |
| Tensile Strength: Yield (Proof), MPa | 430 | |
| 510 |
Thermal Properties
| Latent Heat of Fusion, J/g | 250 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 400 | |
| 400 |
| 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 | 51 | |
| 51 |
| Thermal Expansion, µm/m-K | 13 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 7.2 | |
| 7.2 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 8.2 | |
| 8.3 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 2.0 | |
| 2.0 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 1.6 | |
| 1.6 |
| Embodied Energy, MJ/kg | 22 | |
| 22 |
| Embodied Water, L/kg | 47 | |
| 47 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 110 | |
| 110 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 490 | |
| 690 |
| Stiffness to Weight: Axial, points | 13 | |
| 13 |
| Stiffness to Weight: Bending, points | 24 | |
| 24 |
| Strength to Weight: Axial, points | 19 | |
| 22 |
| Strength to Weight: Bending, points | 19 | |
| 21 |
| Thermal Diffusivity, mm2/s | 14 | |
| 14 |
| Thermal Shock Resistance, points | 16 | |
| 18 |
Alloy Composition
| Carbon (C), % | 0 to 0.25 | |
| 0 to 0.26 |
| Iron (Fe), % | 97.4 to 99.5 | |
| 97.3 to 99.5 |
| Manganese (Mn), % | 0.5 to 1.6 | |
| 0.5 to 1.7 |
| Niobium (Nb), % | 0 to 0.050 | |
| 0 to 0.050 |
| Nitrogen (N), % | 0 to 0.015 | |
| 0 to 0.015 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 0.4 | |
| 0 to 0.4 |
| Sulfur (S), % | 0 to 0.050 | |
| 0 to 0.050 |
| Titanium (Ti), % | 0 to 0.040 | |
| 0 to 0.040 |
| Vanadium (V), % | 0 to 0.15 | |
| 0 to 0.15 |