Steel SKD1-SR (Stress relieved)
Heat-treated state
JIS SKD1 · AISI/SAE D3
Intermediate step after rough machining of large dies to minimise hardening distortion.
Values for the SR condition
Other SKD1 tempers and conditions
SKD1 is listed in 8 conditions; see the grade overview at SKD1.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ESR (electroslag remelted) annealed bar | Premium remelted stock with finer, less banded carbides — pick for large dies, better polish and more isotropic toughness. | 455 | 770 | 14 | 21 HRC | 2.7 % IACS |
ANNDefault Annealed | The as-supplied stock condition for machining dies before hardening. | 460 | 780 | 12 | 22 HRC | — |
SRThis page Stress relieved | Intermediate step after rough machining of large dies to minimise hardening distortion. | 470 | 790 | 11 | 23 HRC | 2.7 % IACS |
Hardened & tempered 55–58 HRC | Higher-temper condition used when dimensional stability or nitriding follow-up matters more than peak hardness. | 1,620 | 1,850 | 1 | 57 HRC | 2.6 % IACS |
Hardened & tempered 58–60 HRC | Slightly tougher setting for heavier sections and shock-loaded shear blades. | — | 1,950 | — | 59 HRC | — |
Hardened + deep-freeze (−75 to −196 °C) + tempered, 63–65 HRC | Choose when retained austenite must be removed for maximum hardness and long-term size stability (gauges, precision punches). | 2,000 | 2,300 | 0.5 | 64 HRC | 2.6 % IACS |
Hardened & tempered 60–62 HRC | The usual working hardness for cold-forming, drawing and thread-rolling tools. | — | 2,100 | — | 61 HRC | — |
Hardened & tempered 62–64 HRC | Maximum wear resistance for blanking punches and dies cutting thin, abrasive material — lowest toughness. | — | 2,250 | 0.5 | 63 HRC | — |
What is SKD1-SR?
SKD1-SR is SKD1 heat treated to SR — intermediate step after rough machining of large dies to minimise hardening distortion. SKD1-SR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 57% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi). SKD1-SR has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,270°C (2,318 °F). ANN is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Good corrosion resistance — 25/100, better than 92% of steel grades
Limitations
- Low fracture toughness — 16 MPa·√m (14.6 ksi·√in), 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
SKD1-SR properties
Typical room-temperature values for SKD1-SR; 23 are specific to this condition. Other listed values are SKD1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SKD1-SR has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 95% of steel grades. It melts at 1,270°C (2,318 °F).
Mechanical16
SKD1-SR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 57% of steel grades. Elongation at break is 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
SKD1-SR 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
SKD1-SR 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 SKD1-SR takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 40%.
Manufacturability8
SKD1-SR's machinability is poor (27/100, worse than 92% of steel grades); weldability poor (18/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SKD1-SR
Is SKD1 easy to machine?
Machine only in the annealed state with rigid setups, sharp carbide or coated-carbide tooling, moderate speeds and generous coolant; hardened SKD1 must be ground or EDM'd, and stress-relieve rough-machined dies before hardening.
Can SKD1 be welded?
Essentially a repair-only operation: preheat to 300–400 °C, use matched high-Cr tool-steel electrodes, keep interpass hot and temper immediately — cold-cracking risk is high.
Can SKD1 be formed, bent or molded?
No cold forming; hot work between about 1050 and 900 °C with slow furnace cooling followed by spheroidize annealing at 850–870 °C.
What surface finishes work on SKD1?
Harden 950–980 °C, oil or pressurised-gas quench, temper twice at 150–250 °C (deep-freeze if size stability is critical); finish with grinding, then nitriding, PVD TiN/CrN or black oxide for wear and light corrosion protection.
SKD1 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 |
|---|---|---|
| CAISI D3 range is 2.00–2.35 | 1.8 – 2.4 | 2.1 |
| Si | ≤ 0.4 | 0.3 |
| Mn | ≤ 0.6 | 0.35 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Crsome JIS/vendor tables quote up to 15 %; D3 is 11.00–13.50 | 11 – 13 | 12 |
| Monot intentionally added; residual/optional | ≤ 0.6 | — |
| Voptional in D3 | ≤ 1 | — |
| Woptional in D3 | ≤ 1 | — |
| Niresidual | ≤ 0.5 | — |
| Curesidual | ≤ 0.25 | — |
| Fe | balance | — |
SKD1-SR — frequently asked
What is SKD1-SR used for?
SKD1-SR is typically used for cold forming dies, thread rolling dies and blanking punches. In short: highest wear resistance, cold-work; D3 equivalent, oil/air hardening; low toughness and machinability.
What is the yield strength of SKD1-SR?
SKD1-SR has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is SKD1-SR easy to machine?
Not especially — machinability is rated poor (27/100, worse than 92% of steel grades). Machine only in the annealed state with rigid setups, sharp carbide or coated-carbide tooling, moderate speeds and generous coolant; hardened SKD1 must be ground or EDM'd, and stress-relieve rough-machined dies before hardening.
Can SKD1-SR be welded?
Not readily — weldability is rated poor (18/100). Essentially a repair-only operation: preheat to 300–400 °C, use matched high-Cr tool-steel electrodes, keep interpass hot and temper immediately — cold-cracking risk is high.
What surface finishes work on SKD1-SR?
Harden 950–980 °C, oil or pressurised-gas quench, temper twice at 150–250 °C (deep-freeze if size stability is critical); finish with grinding, then nitriding, PVD TiN/CrN or black oxide for wear and light corrosion protection.
Can SKD1-SR be formed, bent or molded?
No cold forming; hot work between about 1050 and 900 °C with slow furnace cooling followed by spheroidize annealing at 850–870 °C.
What is the maximum service temperature of SKD1-SR?
SKD1-SR 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 SKD1-ANN and SKD1 QT-CRYO?
ANN is the default condition — the as-supplied stock condition for machining dies before hardening. QT-CRYO: choose when retained austenite must be removed for maximum hardness and long-term size stability (gauges, precision punches). Yield strength is 460 MPa in ANN versus 2,000 MPa in QT-CRYO.
Sources
- JIS G 4404 — Alloy tool steels — Japanese Standards Association (2015)
- ASTM A681 — Standard Specification for Tool Steels Alloy (Type D3) — ASTM International (2015)
- GB/T 1299 — (Cr12) — SAC (2014)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys (Cold-Work Tool Steels) — ASM International (1990)
- ASM Handbook Vol.16: Machining (machinability ratings of tool steels) — ASM International (1989)
- 1.2080 / D3 cold-work tool steel datasheet — Böhler / Daido / Hitachi Metals equivalents (2022)
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.