Steel D7-ANN vs D7 HT-64
Steel · D7 temper comparison
D7-ANN and D7 HT-64 are two conditions of the same steel grade, D7: ANN (annealed) versus HT-64 (hardened & tempered 150–260 °C). The chemistry is identical, so every difference below comes from the condition. D7 HT-64 is the stronger of the two: yield strength 2,000 MPa (290 ksi) against 500 MPa (72.5 ksi) for D7-ANN, about 4.0 times as much; tensile strength follows at 2,200 MPa (319 ksi) vs 860 MPa (125 ksi). In exchange, D7-ANN is the more ductile: elongation 10% versus 0.5% for D7 HT-64, and D7 HT-64 is harder (64 HRC vs 24 HRC). D7-ANN runs hotter in service (400°C vs 180°C continuous). On the shop floor, D7-ANN machines more easily (poor vs not recommended).
D7-ANNChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
D7 HT-64Choose it when strength drives the design.
D7-ANN vs D7 HT-64: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Hardness, Brinell 248 HB
Physical
Density and transition temperatures.
Same in both: Density 7.67 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,250°C2,282 °F · Liquidus Temperature 1,380°C2,516 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 20 W/m·K11.6 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.7 % IACS · Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.4 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Brazeability / Solderability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 70 L/kg8.4 gal/lb · Typical Recycled Content 45%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
D7-ANN vs D7 HT-64 — frequently asked
Is D7 HT-64 stronger than D7-ANN?
Yes. D7 HT-64 has a typical yield strength of 2,000 MPa (290 ksi) against 500 MPa (72.5 ksi) for D7-ANN — about 4.0 times as much. Tensile strength is 2,200 MPa (319 ksi) vs 860 MPa (125 ksi).
Which condition does FabDigit quote by default, ANN or HT-64?
ANN is the default D7 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, D7-ANN or D7 HT-64?
D7-ANN. Its machinability rates poor (22/100) against not recommended (3/100) for D7 HT-64; for welding the order is D7-ANN first (not recommended, 12/100) then D7 HT-64 (not recommended, 3/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in D7-ANN and D7 HT-64 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.