Steel D7 HT-64
Heat-treated state
AISI/SAE D7 · UNS T30407
HT-64 = hardened & tempered 150–260 °C
Standard working condition: austenitize ~1010–1065 °C, air/oil quench, low temper — pick for maximum abrasion life where impact is minimal.
Values for the HT-64 condition
Other D7 tempers and conditions
D7 is listed in 5 conditions; see the grade overview at D7.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard mill supply condition for rough machining before hardening; still hard to cut due to massive V/Cr carbides. | 500 | 860 | 10 | 24 HRC | — |
Hardened & double tempered 510–540 °C | Use when the tool must resist warm working, nitriding or PVD coating temperatures near 500 °C. | 1,750 | 1,950 | 1 | 59 HRC | — |
Hardened & tempered ~300–425 °C | Slightly softer, less brittle setting for dies with some edge loading or larger sections. | 1,850 | 2,050 | 1 | 60 HRC | — |
Hardened + deep cryogenic (−80 to −196 °C) + double temper | Specify when retained austenite must be minimized for dimensional stability and top abrasion life on gauge/press tooling. | 1,900 | 2,250 | 0.5 | 65 HRC | 2.5 % IACS |
HT-64This page Hardened & tempered 150–260 °C | Standard working condition: austenitize ~1010–1065 °C, air/oil quench, low temper — pick for maximum abrasion life where impact is minimal. | 2,000 | 2,200 | 0.5 | 64 HRC | 20 W/m·K |
What is D7 HT-64?
D7 HT-64 is D7 heat treated to HT-64 — standard working condition: austenitize ~1010–1065 °C, air/oil quench, low temper — pick for maximum abrasion life where impact is minimal. D7 HT-64 has a yield strength of 2,000 MPa (290 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 210 GPa (30.5 Msi). D7 HT-64 has a density of 7.67 g/cm³ (0.277 lb/in³), lighter than 96% of steel grades. It melts at 1,250°C (2,282 °F). ANN is the default condition FabDigit quotes; HT-64 is available on request or by drawing note.
Advantages
- High strength — 2,000 MPa (290 ksi), better than 100% of steel grades
- Good corrosion resistance — 27/100, better than 93% of steel grades
Limitations
- Limited ductility — 0.5%, worse than 100% of steel grades
- Low fracture toughness — 13 MPa·√m (11.8 ksi·√in), worse than 100% of steel grades
- Difficult to machine — 3/100, worse than 100% of steel grades
- Difficult to weld — 3/100, worse than 100% of steel grades
- Limited formability — 1/100, worse than 100% of steel grades
D7 HT-64 properties
Typical room-temperature values for D7 HT-64; 21 are specific to this condition. Other listed values are D7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
D7 HT-64 has a density of 7.67 g/cm³ (0.277 lb/in³), lighter than 96% of steel grades. It melts at 1,250°C (2,282 °F).
Mechanical16
D7 HT-64 has a yield strength of 2,000 MPa (290 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
D7 HT-64 is rated for continuous service to 180°C (356 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
D7 HT-64 conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (27/100), better than 93% of steel grades.
Sustainability4
Producing a kilogram of D7 HT-64 takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 45%.
Manufacturability6
D7 HT-64's machinability is not recommended (3/100, worse than 100% of steel grades); weldability not recommended (3/100); formability not recommended (1/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with D7 HT-64
Is D7 easy to machine?
Machine only in the annealed state with rigid setups, low speeds and TiAlN-coated carbide or CBN; after hardening plan on grinding (CBN/SG wheels), EDM or wire EDM.
Can D7 be welded?
Essentially not weldable for structural joints; repair-weld only preheated to 300–400 °C with matching high-alloy filler and immediate re-temper.
Can D7 be formed, bent or molded?
Hot work at 1050–900 °C with slow, uniform reduction and immediate slow cool/anneal; no cold forming — the carbide network cracks.
What surface finishes work on D7?
Takes a good but not mirror finish (primary carbides pull out); commonly nitrided or PVD (TiCN/AlCrN) coated, and must be oiled or coated for rust protection.
D7 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CASTM A681 D7 | 2.15 – 2.5 | 2.35 |
| Mn | 0.2 – 0.8 | 0.5 |
| Si | 0.1 – 0.6 | 0.4 |
| Cr | 11.5 – 13.5 | 12.5 |
| Mo | 0.7 – 1.2 | 1 |
| Vforms MC vanadium carbides — source of abrasion resistance | 3.8 – 4.4 | 4 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
D7 HT-64 — frequently asked
What is D7 HT-64 used for?
D7 HT-64 is typically used for abrasive-wear dies, brick molds, extreme wear liners and long-run blanking punches. In short: most wear-resistant D-series; highest vanadium cold-work steel; grind hardened, do not mill.
What is the yield strength of D7 HT-64?
D7 HT-64 has a typical yield strength of 2,000 MPa (290 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is D7 HT-64 easy to machine?
Not especially — machinability is rated not recommended (3/100, worse than 100% of steel grades). Machine only in the annealed state with rigid setups, low speeds and TiAlN-coated carbide or CBN; after hardening plan on grinding (CBN/SG wheels), EDM or wire EDM.
Can D7 HT-64 be welded?
Not readily — weldability is rated not recommended (3/100). Essentially not weldable for structural joints; repair-weld only preheated to 300–400 °C with matching high-alloy filler and immediate re-temper.
What surface finishes work on D7 HT-64?
Takes a good but not mirror finish (primary carbides pull out); commonly nitrided or PVD (TiCN/AlCrN) coated, and must be oiled or coated for rust protection.
Can D7 HT-64 be formed, bent or molded?
Hot work at 1050–900 °C with slow, uniform reduction and immediate slow cool/anneal; no cold forming — the carbide network cracks.
What is the maximum service temperature of D7 HT-64?
D7 HT-64 is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between D7-ANN and D7 HT-64?
ANN is the default condition — standard mill supply condition for rough machining before hardening; still hard to cut due to massive V/Cr carbides. HT-64: standard working condition: austenitize ~1010–1065 °C, air/oil quench, low temper — pick for maximum abrasion life where impact is minimal. Yield strength is 500 MPa in ANN versus 2,000 MPa in HT-64.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
- DIN EN ISO 4957 — Tool steels (X205CrMoV12-1 / 1.2378 nearest EN grade) — ISO/DIN (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- Cold-work tool steel datasheets (D-series / 1.2378 heat-treatment and hardness data) — various tool-steel producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.