Steel D7
AISI/SAE D7 · UNS T30407
Highest-carbide, highest-vanadium member of the D-series cold-work steels, delivering maximum abrasion resistance at the expense of machinability and toughness; used for the most severe wear applications.
Reference datasheet — D7 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
D7 tempers and conditions
D7 is supplied in 5 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
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 |
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?
Highest-carbide, highest-vanadium member of the D-series cold-work steels, delivering maximum abrasion resistance at the expense of machinability and toughness; used for the most severe wear applications. D7 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). D7 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 63% of steel grades. Elongation at break is 10% and the elastic modulus is 207 GPa (30 Msi).
What is D7 used for?
- abrasive-wear dies
- brick molds
- extreme wear liners
- long-run blanking punches
Advantages
- Good corrosion resistance — 22/100, better than 90% of steel grades
Limitations
- Low fracture toughness — 22 MPa·√m (20 ksi·√in), worse than 98% of steel grades
- Poor heat conductor — 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Difficult to machine — 22/100, worse than 95% of steel grades
D7 properties
Typical room-temperature values for D7-ANN; bars are the position among steel grades.
Physical3
D7 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 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 63% of steel grades. Elongation at break is 10% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
D7 is rated for continuous service to 400°C (752 °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 conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of D7 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's machinability is poor (22/100, worse than 95% of steel grades); weldability not recommended (12/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. D7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with D7
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel D7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T30407
- Similar grades
- 1.2378X205CrMoV12-1
How much does D7 cost?
D7 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
D7 — frequently asked
What is D7 used for?
D7 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?
D7 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is D7 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% 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 be welded?
Not readily — weldability is rated not recommended (12/100). 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?
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 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?
D7 is rated for continuous use to about 400°C (752 °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.
How much does D7 cost?
D7 is a high-cost steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.