Steel D6
AISI/SAE D6 · UNS T30406
D6 is a tungsten-alloyed high-carbon, high-chromium cold-work tool steel (UNS T30406) in which tungsten additions supplement the chromium carbide network for maximum abrasion resistance.
Reference datasheet — D6 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 Annealed condition
D6 tempers and conditions
D6 is supplied in 5 conditions, soft to hard. Annealed 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 |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize annealed, as-supplied bar/plate | Standard stocking condition for machining/EDM of the die blank before hardening. | 450 | 800 | 15 | 22 HRC | — |
Oil quenched, tempered ~400–450 °C | Pick when some shock loading is expected and maximum wear life can be traded for a little toughness. | 1,900 | 1 | 57 HRC | — | |
Oil quenched, tempered ~250–300 °C | Balanced working hardness for thicker blanking punches and forming dies in heavier sections. | 2,050 | 0.5 | 59 HRC | — | |
Oil quenched, tempered ~180–220 °C | Most common in-service hardness for high-volume blanking, trimming and thread-rolling tools. | 2,150 | 0 | 61 HRC | — | |
Oil quenched, low temper ~150–180 °C | Maximum wear resistance for thin, well-supported cutting edges on abrasive sheet or laminations; least tolerance for shock. | 2,200 | 0 | 63 HRC | — |
What is D6?
D6 is a tungsten-alloyed high-carbon, high-chromium cold-work tool steel (UNS T30406) in which tungsten additions supplement the chromium carbide network for maximum abrasion resistance. It is used for heavy-duty blanking dies, deep-draw dies and forming rolls in high-volume abrasive work, supplied annealed and hardened to 56–64 HRC. It is the least machinable grade of the D group, is oil quenched with real distortion and cracking risk, shows low hardenability in thick sections and is limited to about 200 °C service. D1 or D2 is the more forgiving choice when toughness and machining cost matter. D6 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,250°C (2,282 °F). D6 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 52% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
What is D6 used for?
- heavy-duty blanking dies
- deep-draw dies
- forming rolls
Advantages
- Good corrosion resistance — 25/100, better than 92% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 8/100, worse than 97% 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
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
D6 properties
Typical room-temperature values for D6-Annealed; bars are the position among steel grades.
Physical3
D6 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,250°C (2,282 °F).
Mechanical13
D6 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 52% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal5
D6 is rated for continuous service to 200°C (392 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
D6 conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of D6 takes about 40 MJ of energy and emits 2.9 kg of CO₂ — more than 91% of steel grades. Typical recycled content is 40%.
Manufacturability7
D6's machinability is poor (30/100, worse than 89% of steel grades); weldability not recommended (10/100); formability not recommended (8/100).
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. D6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with D6
Is D6 easy to machine?
Machine only in the annealed condition with rigid setups, low speeds and hard-carbide or CBN tooling; hardened D6 is a grind/EDM-only material and grinds slowly because of the coarse carbide network.
Can D6 be welded?
Essentially unweldable for structural purposes; repair only with preheat 300–350 °C, matching high-alloy filler, small stringer beads and an immediate temper, otherwise cracking is near-certain.
Can D6 be formed, bent or molded?
No cold forming; hot work at 900–1050 °C with slow, controlled cooling and a mandatory 800–850 °C anneal, then oil quench from ~950–980 °C and temper at 150–250 °C for working hardness (expect distortion and low hardenability in thick sections).
D6 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 |
|---|---|---|
| Chigh carbon for dense M7C3 carbide network | 2 – 2.35 | 2.15 |
| Cr | 11 – 13 | 12 |
| Wdistinguishing addition vs D3; JIS SKD2 uses 0.60–0.80 | 0.6 – 1.2 | 0.85 |
| Mn | 0.15 – 0.6 | 0.35 |
| Si | 0.1 – 0.6 | 0.3 |
| Voptional/residual; up to 0.5 in SKD2 | ≤ 0.5 | 0.2 |
| Moresidual only | ≤ 0.3 | |
| Niresidual | ≤ 0.3 | |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on D6?
Take polish well after hardening but carbide banding can streak mirror finishes; protect with oil, black oxide, hard chrome, nitriding or CrN/TiCN PVD coatings applied below the tempering temperature.
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 D6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T30406
How much does D6 cost?
D6 is a standard-cost steel ($$), cheaper than about 71% 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.
D6 — frequently asked
What is D6 used for?
D6 is typically used for heavy-duty blanking dies, deep-draw dies and forming rolls. In short: most wear-resistant D-series; tungsten-boosted abrasion resistance; lowest machinability of family.
What is the yield strength of D6?
D6 has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is D6 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 89% of steel grades). Machine only in the annealed condition with rigid setups, low speeds and hard-carbide or CBN tooling; hardened D6 is a grind/EDM-only material and grinds slowly because of the coarse carbide network.
Can D6 be welded?
Not readily — weldability is rated not recommended (10/100). Essentially unweldable for structural purposes; repair only with preheat 300–350 °C, matching high-alloy filler, small stringer beads and an immediate temper, otherwise cracking is near-certain.
What surface finishes work on D6?
Take polish well after hardening but carbide banding can streak mirror finishes; protect with oil, black oxide, hard chrome, nitriding or CrN/TiCN PVD coatings applied below the tempering temperature.
Can D6 be formed, bent or molded?
No cold forming; hot work at 900–1050 °C with slow, controlled cooling and a mandatory 800–850 °C anneal, then oil quench from ~950–980 °C and temper at 150–250 °C for working hardness (expect distortion and low hardenability in thick sections).
What is the maximum service temperature of D6?
D6 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does D6 cost?
D6 is a standard-cost steel ($$), cheaper than about 71% 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 — Alloy Tool Steels (D-series chemistry framework) — ASTM International (2020)
- JIS G 4404 — Alloy tool steels (SKD2) — JSA (2015)
- DIN EN ISO 4957 — Tool steels (X210CrW12 / 1.2436) — DIN (2018)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- ASM Handbook Vol. 16 — Machining (machinability ratings of tool steels) — ASM International (1989)
- Cold-work tool steel 1.2436 / X210CrW12 datasheet — European tool steel producers (typical published physical data) (2022)
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.