Steel SUP9 Cold Drawn
Supply condition
GB SUP9
Chosen for close dimensional tolerance and bright surface on small bar and wire prior to hardening.
Values for the Cold Drawn condition
Other SUP9 tempers and conditions
SUP9 is listed in 6 conditions; see the grade overview at SUP9.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
softest condition for cold forming | Pick when severe cold bending, upsetting or deep machining is needed before hardening. | 400 | 680 | 26 | 10 HRC | 8 % IACS |
AnnealedDefault full anneal, soft condition | Default stock condition for machining, cold forming and subsequent heat treatment. | 440 | 760 | 22 | 217 HB | — |
air cooled from ~870 °C | Use to homogenise structure and refine grain before final quench and temper. | 530 | 960 | 17 | 27 HRC | 7.8 % IACS |
as-rolled bar / flat stock | Mill as-supplied condition for spring makers who will form then quench and temper themselves. | 570 | 950 | 13 | 28 HRC | — |
Cold DrawnThis page annealed then cold drawn bar/wire | Chosen for close dimensional tolerance and bright surface on small bar and wire prior to hardening. | 720 | 900 | 10 | 26 HRC | 7.8 % IACS |
oil quenched, low temper to ≈48–52 HRC | Pick for blades, agricultural tines, scrapers and wear parts where hardness matters more than toughness. | 1,500 | 1,700 | 6 | 50 HRC | — |
What is SUP9 Cold Drawn?
SUP9 Cold Drawn is SUP9 supplied in the Cold Drawn condition — chosen for close dimensional tolerance and bright surface on small bar and wire prior to hardening. SUP9 Cold Drawn has a yield strength of 720 MPa (104 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 82% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). SUP9 Cold Drawn has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Cold Drawn is available on request or by drawing note.
Advantages
- High strength — 720 MPa (104 ksi), better than 82% of steel grades
Limitations
- Limited ductility — 10%, worse than 91% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
SUP9 Cold Drawn properties
Typical room-temperature values for SUP9 Cold Drawn; 23 are specific to this condition. Other listed values are SUP9 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SUP9 Cold Drawn has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical14
SUP9 Cold Drawn has a yield strength of 720 MPa (104 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 82% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SUP9 Cold Drawn is rated for continuous service to 300°C (572 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SUP9 Cold Drawn conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of SUP9 Cold Drawn takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
SUP9 Cold Drawn's machinability is good (58/100, better than 75% of steel grades); weldability poor (28/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SUP9 Cold Drawn
Is SUP9 easy to machine?
Machine in the annealed/spheroidised state (≈60 % of 1212); above ~40 HRC use carbide or grind, and expect rapid tool wear.
Can SUP9 be welded?
Poor weldability due to high carbon equivalent — preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper, and re-heat-treat if the joint is load bearing.
Can SUP9 be formed, bent or molded?
Hot form 850–1050 °C or cold bend only when soft-annealed; harden by oil quench from 830–860 °C and temper 400–500 °C for spring temper.
What surface finishes work on SUP9?
No natural corrosion protection: shot peen for fatigue, then phosphate+oil, zinc/zinc-flake plating or epoxy paint; avoid hydrogen-embrittling plating without bake-out.
SUP9 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 |
|---|---|---|
| CSUP9A: 0.56–0.64 | 0.52 – 0.6 | 0.56 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.65 – 0.95 | 0.8 |
| CrSUP9A: 0.70–1.00 | 0.65 – 0.95 | 0.8 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Curesidual, max | ≤ 0.3 | — |
| Niresidual, max | ≤ 0.25 | — |
| Fe | balance | — |
SUP9 Cold Drawn — frequently asked
What is SUP9 Cold Drawn used for?
SUP9 Cold Drawn is typically used for coil springs, leaf springs and springs. In short: premium chromium spring bar.
What is the yield strength of SUP9 Cold Drawn?
SUP9 Cold Drawn has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 82% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is SUP9 Cold Drawn easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine in the annealed/spheroidised state (≈60 % of 1212); above ~40 HRC use carbide or grind, and expect rapid tool wear.
Can SUP9 Cold Drawn be welded?
Not readily — weldability is rated poor (28/100). Poor weldability due to high carbon equivalent — preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper, and re-heat-treat if the joint is load bearing.
What surface finishes work on SUP9 Cold Drawn?
No natural corrosion protection: shot peen for fatigue, then phosphate+oil, zinc/zinc-flake plating or epoxy paint; avoid hydrogen-embrittling plating without bake-out.
Can SUP9 Cold Drawn be formed, bent or molded?
Hot form 850–1050 °C or cold bend only when soft-annealed; harden by oil quench from 830–860 °C and temper 400–500 °C for spring temper.
What is the maximum service temperature of SUP9 Cold Drawn?
SUP9 Cold Drawn is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in SUP9 Cold Drawn?
Yes — SUP9 Cold Drawn is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 4801 — Spring steels — JSA (2021)
- GB/T 1222 — (55CrMnA / 60CrMnA) — SAC (2016)
- ASTM A689 / SAE J404 (5160) — ASTM / SAE (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining; Vol.19 — Fatigue and Fracture — ASM International (1996)
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.