Steel 1.2379
EN 1.2379 · JIS SKD11
1.2379 (X153CrMoV12, AISI D2, JIS SKD11) is a high-carbon, 12 % chromium cold-work tool steel that air-hardens with almost no dimensional change in heat treatment.
Values for the Annealed condition
1.2379 tempers and conditions
1.2379 is supplied in 7 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft annealed / spheroidized, ≤255 HB | Standard as-delivered condition for bar, plate and precision-ground flat stock; machine here, then harden. | 480 | 800 | 12 | 235 HB | — |
Electro-slag remelted, annealed | Specify for large or highly stressed tools and for polished/mirror-finish work: finer, more uniform carbides give better toughness and less directionality. | 490 | 810 | 14 | 20 HRC | 2.7 % IACS |
Secondary-hardening temper ~500–525 °C | High-temperature temper used when the tool will be nitrided, PVD-coated or run warm; better dimensional stability, lower toughness than the 300 °C temper. | 1,500 | 1,750 | 1.5 | 55 HRC | 2.6 % IACS |
hardened/tempered core plus plasma or gas nitrided case | Choose when adhesive wear or galling dominates; thin (0.02–0.1 mm) case at ~1100 HV over a 54–58 HRC core, but case is brittle and cannot be reground away. | 1,520 | 1,780 | 1 | 56 HRC | 2.5 % IACS |
Hardened, tempered ~300–350 °C | Slightly softer, tougher setting for tools with thin sections or heavy shock, where chipping is the main failure mode. | 1,550 | 1,800 | 1.5 | 57 HRC | 2.5 % IACS |
Hardened, tempered ~200–250 °C | The most common working hardness: best balance of wear resistance and chipping resistance for general cold-work tooling. | 1,950 | 59 HRC | — | ||
Hardened ~1020–1040 °C, tempered 180–200 °C | Maximum wear resistance and edge retention for blanking/punching thin, hard sheet; lowest toughness, use generous radii. | 2,100 | 0 | 61 HRC | — |
What is 1.2379?
1.2379 (X153CrMoV12, AISI D2, JIS SKD11) is a high-carbon, 12 % chromium cold-work tool steel that air-hardens with almost no dimensional change in heat treatment. The large volume fraction of chromium carbides gives high abrasive wear resistance at 58–62 HRC, which is why it dominates blanking, punching, cold-forming, shear-blade and thread-rolling tooling; it is stocked annealed at 235 HB in plate and bar, including ESR quality. Limits are low toughness, poor grindability and weldability, carbide-banding anisotropy in thick sections, and only semi-stainless behaviour — it rusts unless polished and oiled. 1.2379 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,420°C (2,588 °F). 1.2379 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 1.2379 used for?
- Cold blanking and piercing dies
- Punches and die buttons
- Shear and slitter blades
- Thread-rolling dies
- Cold-forming and coining tooling
- Trim dies
- Wear plates and guide rails
Advantages
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
Limitations
- 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
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
1.2379 properties
Typical room-temperature values for 1.2379-Annealed; bars are the position among steel grades.
Physical3
1.2379 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical12
1.2379 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal5
1.2379 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 10.9 µm/m·K (6.06 µin/in·°F).
Electrical3
1.2379 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 1.2379 takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 40%.
Manufacturability8
1.2379's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (15/100); formability poor (15/100).
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. 1.2379 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.2379
Is 1.2379 easy to machine?
Machine only in the annealed state with rigid setups, coated carbide and moderate speeds; the ~12 % carbide volume abrades tooling fast, and hardened tools are finished by grinding, EDM or hard-turning with CBN.
Can 1.2379 be welded?
Poor weldability — repair only, with 300–450 °C preheat, matched high-alloy filler, small stringer beads and an immediate temper; never weld in service without post-heat.
Can 1.2379 be formed, bent or molded?
Not a forming grade: hot work at 900–1080 °C with slow cooling and mandatory soft anneal at 830–870 °C; harden 1020–1040 °C, air/vacuum quench, then temper at least twice — allow ~0.05–0.1 % growth.
Manufacturability
The process limits FabDigit's quote engine applies to 1.2379. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Poor35 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
1.2379 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 |
|---|---|---|
| C | 1.45 – 1.6 | 1.53 |
| Si | 0.1 – 0.6 | 0.3 |
| Mn | 0.2 – 0.6 | 0.3 |
| Cr | 11 – 13 | 11.8 |
| Mo | 0.7 – 1 | 0.8 |
| V | 0.7 – 1 | 0.8 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 1.2379?
Takes a fine mirror polish when hardened (ESR grades best); protect with oil, black oxide, hard chrome, nitriding or PVD TiCN/CrN since the alloy stains readily in humid air.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 1.2379 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- JIS
- SKD11
How much does 1.2379 cost?
1.2379 is a premium-cost steel ($$$), pricier than about 57% 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.
1.2379 — frequently asked
What is 1.2379 used for?
1.2379 is typically used for cold blanking and piercing dies, punches and die buttons, shear and slitter blades, thread-rolling dies, cold-forming and coining tooling and trim dies. In short: premium cold-work tool.
What is the yield strength of 1.2379?
1.2379 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.2379 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Machine only in the annealed state with rigid setups, coated carbide and moderate speeds; the ~12 % carbide volume abrades tooling fast, and hardened tools are finished by grinding, EDM or hard-turning with CBN.
Can 1.2379 be welded?
Not readily — weldability is rated poor (15/100). Poor weldability — repair only, with 300–450 °C preheat, matched high-alloy filler, small stringer beads and an immediate temper; never weld in service without post-heat.
What surface finishes work on 1.2379?
Takes a fine mirror polish when hardened (ESR grades best); protect with oil, black oxide, hard chrome, nitriding or PVD TiCN/CrN since the alloy stains readily in humid air.
Can 1.2379 be formed, bent or molded?
Not a forming grade: hot work at 900–1080 °C with slow cooling and mandatory soft anneal at 830–870 °C; harden 1020–1040 °C, air/vacuum quench, then temper at least twice — allow ~0.05–0.1 % growth.
What is the maximum service temperature of 1.2379?
1.2379 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.
What is the difference between 1.2379 Annealed and 1.2379-ESR?
Annealed is the default condition — standard as-delivered condition for bar, plate and precision-ground flat stock; machine here, then harden. ESR: specify for large or highly stressed tools and for polished/mirror-finish work: finer, more uniform carbides give better toughness and less directionality. Yield strength is 480 MPa in Annealed versus 490 MPa in ESR.
How much does 1.2379 cost?
1.2379 is a premium-cost steel ($$$), pricier than about 57% 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.
Can FabDigit make parts in 1.2379?
Yes — 1.2379 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN ISO 4957 — Tool steels (X153CrMoV12) — ISO/CEN (2018)
- ASTM A681 — Alloy tool steels (Type D2) — ASTM (2015)
- GB/T 1299 — Tool and die steels (Cr12Mo1V1) — SAC (2014)
- Sverker 21 cold work tool steel — Uddeholm (2023)
- BÖHLER K110 datasheet — voestalpine Böhler Edelstahl (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- (SKD11/Cr12Mo1V1) — Mysteel / 1688 (2026)
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.