Steel 1.2379-ESR
Grade
EN 1.2379 · JIS SKD11
ESR = 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.
Values for the ESR condition
Other 1.2379 tempers and conditions
1.2379 is listed in 7 conditions; see the grade overview at 1.2379.
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 | — |
ESRThis page 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-ESR?
1.2379-ESR is 1.2379 in the ESR grade — specify for large or highly stressed tools and for polished/mirror-finish work: finer, more uniform carbides give better toughness and less directionality. 1.2379-ESR has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 61% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). 1.2379-ESR 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). Annealed is the default condition FabDigit quotes; ESR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 100% of steel grades
- Good corrosion resistance — 27/100, better than 93% 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 — 16/100, worse than 88% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
1.2379-ESR properties
Typical room-temperature values for 1.2379-ESR; 24 are specific to this condition. Other listed values are 1.2379 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1.2379-ESR 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-ESR has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 61% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal5
1.2379-ESR 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-ESR 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 1.2379-ESR 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-ESR's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (16/100); formability poor (17/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.2379-ESR
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.
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.
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 | — |
1.2379-ESR — frequently asked
What is 1.2379-ESR used for?
1.2379-ESR 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-ESR?
1.2379-ESR has a typical yield strength of 490 MPa (71.1 ksi) and a tensile strength of 810 MPa (117 ksi) — stronger than 61% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.2379-ESR easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% 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-ESR be welded?
Not readily — weldability is rated poor (16/100). 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-ESR?
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-ESR 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-ESR?
1.2379-ESR 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.
Can FabDigit make parts in 1.2379-ESR?
Yes — 1.2379-ESR 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.