ASTM Grade HT Steel vs. ASTM Grade HH Steel
Both ASTM grade HT steel and ASTM grade HH steel are iron alloys. Both are furnished in the as-fabricated (no temper or treatment) condition. They have 77% of their average alloy composition in common.
For each property being compared, the top bar is ASTM grade HT steel and the bottom bar is ASTM grade HH steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 150 | |
| 170 |
| Elastic (Young's, Tensile) Modulus, GPa | 190 | |
| 200 |
| Elongation at Break, % | 4.6 | |
| 11 |
| Fatigue Strength, MPa | 130 | |
| 150 |
| Poisson's Ratio | 0.28 | |
| 0.27 |
| Shear Modulus, GPa | 76 | |
| 79 |
| Tensile Strength: Ultimate (UTS), MPa | 500 | |
| 580 |
| Tensile Strength: Yield (Proof), MPa | 270 | |
| 270 |
Thermal Properties
| Latent Heat of Fusion, J/g | 310 | |
| 310 |
| Maximum Temperature: Corrosion, °C | 400 | |
| 440 |
| Maximum Temperature: Mechanical, °C | 1010 | |
| 1100 |
| Melting Completion (Liquidus), °C | 1390 | |
| 1400 |
| Melting Onset (Solidus), °C | 1340 | |
| 1360 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 480 |
| Thermal Conductivity, W/m-K | 12 | |
| 14 |
| Thermal Expansion, µm/m-K | 15 | |
| 17 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 1.7 | |
| 2.1 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 1.9 | |
| 2.4 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 31 | |
| 20 |
| Density, g/cm3 | 8.0 | |
| 7.7 |
| Embodied Carbon, kg CO2/kg material | 5.4 | |
| 3.7 |
| Embodied Energy, MJ/kg | 76 | |
| 53 |
| Embodied Water, L/kg | 190 | |
| 180 |
Common Calculations
| PREN (Pitting Resistance) | 18 | |
| 27 |
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 19 | |
| 53 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 180 | |
| 190 |
| Stiffness to Weight: Axial, points | 13 | |
| 14 |
| Stiffness to Weight: Bending, points | 24 | |
| 25 |
| Strength to Weight: Axial, points | 18 | |
| 21 |
| Strength to Weight: Bending, points | 18 | |
| 20 |
| Thermal Diffusivity, mm2/s | 3.2 | |
| 3.8 |
| Thermal Shock Resistance, points | 12 | |
| 12 |
Alloy Composition
| Carbon (C), % | 0.35 to 0.75 | |
| 0.2 to 0.5 |
| Chromium (Cr), % | 15 to 19 | |
| 24 to 28 |
| Iron (Fe), % | 38.2 to 51.7 | |
| 52.9 to 64.8 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0 to 2.0 |
| Molybdenum (Mo), % | 0 to 0.5 | |
| 0 to 0.5 |
| Nickel (Ni), % | 33 to 37 | |
| 11 to 14 |
| Phosphorus (P), % | 0 to 0.040 | |
| 0 to 0.040 |
| Silicon (Si), % | 0 to 2.5 | |
| 0 to 2.0 |
| Sulfur (S), % | 0 to 0.040 | |
| 0 to 0.040 |