Steel SUP9 Spheroidize Annealed
Heat-treated state
GB SUP9
Pick when severe cold bending, upsetting or deep machining is needed before hardening.
Values for the Spheroidize Annealed condition
Other SUP9 tempers and conditions
SUP9 is listed in 6 conditions; see the grade overview at SUP9.
- Spheroidize Annealed
- Annealed
- Normalized
- Hot Rolled
- Cold Drawn
- Hardened & Tempered
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize AnnealedThis page 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 | — |
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 Spheroidize Annealed?
SUP9 Spheroidize Annealed is SUP9 heat treated to Spheroidize Annealed — pick when severe cold bending, upsetting or deep machining is needed before hardening. SUP9 Spheroidize Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi). SUP9 Spheroidize Annealed 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; Spheroidize Annealed is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
SUP9 Spheroidize Annealed properties
Typical room-temperature values for SUP9 Spheroidize Annealed; 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 Spheroidize Annealed 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 Spheroidize Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SUP9 Spheroidize Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SUP9 Spheroidize Annealed conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of SUP9 Spheroidize Annealed 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 Spheroidize Annealed's machinability is good (60/100, better than 83% of steel grades); weldability fair (40/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SUP9 Spheroidize Annealed
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 Spheroidize Annealed — frequently asked
What is SUP9 Spheroidize Annealed used for?
SUP9 Spheroidize Annealed is typically used for coil springs, leaf springs and springs. In short: premium chromium spring bar.
What is the yield strength of SUP9 Spheroidize Annealed?
SUP9 Spheroidize Annealed has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 680 MPa (98.6 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is SUP9 Spheroidize Annealed easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% 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 Spheroidize Annealed be welded?
With care — weldability is rated fair (40/100). 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 Spheroidize Annealed?
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 Spheroidize Annealed 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 Spheroidize Annealed?
SUP9 Spheroidize Annealed is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in SUP9 Spheroidize Annealed?
Yes — SUP9 Spheroidize Annealed 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.