Steel SUP10 · temper · default condition
Steel SUP10 Annealed
Properties of the Annealed condition, compared with the other SUP10 tempers.
Stock condition for machining, cold forming and pre-heat-treat blanks before quench and temper.
What is SUP10 Annealed?
SUP10 Annealed is SUP10 in the Annealed temper — stock condition for machining, cold forming and pre-heat-treat blanks before quench and temper. SUP10 Annealed has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 206 GPa (29.9 Msi). SUP10 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).
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
SUP10 Annealed properties
Typical room-temperature values for SUP10 Annealed — 11 properties are specific to this condition; the rest are grade-level values shared by every SUP10 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
SUP10 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
SUP10 Annealed has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SUP10 Annealed is rated for continuous service to 200°C (392 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
SUP10 Annealed conducts electricity at 7.5 % IACS, worse than 68% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SUP10 Annealed takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability7
SUP10 Annealed's machinability is good (55/100, better than 62% of steel grades); weldability poor (25/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other SUP10 tempers and conditions
SUP10 is also supplied in 7 other conditions. The full side-by-side table is on the SUP10 overview.
- AnnealedDefaultStock condition for machining, cold forming and pre-heat-treat blanks before quench and temper.480 MPa yield · 210 HB
- Hardened & TemperedPick when maximum strength/wear is needed (valve springs, hand tools, chisels) and toughness can be traded away.1,500 MPa yield · 48 HRC
- Q&TStandard spring condition: highest usable strength with adequate toughness for leaf, coil and torsion springs.1,300 MPa yield · 44 HRC
- Q&T 38-42 HRCUse where fatigue with impact loading matters more than peak stress (stabiliser bars, heavy leaf springs).1,120 MPa yield · 40 HRC
Working with SUP10 Annealed
Is SUP10 easy to machine?
Machine in the annealed condition (~55 % of 1212) with rigid setups and carbide at moderate speed; above 40 HRC switch to grinding, CBN or EDM.
Can SUP10 be welded?
Effectively not weldable in the hardened state — high carbon equivalent causes cracking; if unavoidable, preheat 300–350 °C, low-hydrogen consumables and re-quench/temper the whole part.
Can SUP10 be formed, bent or molded?
Cold form or coil only when annealed or as oil-tempered wire; hot forge 1050–1150 °C, finish above 900 °C, slow cool, then harden from 830–870 °C in oil and temper 400–500 °C.
What surface finishes work on SUP10?
No corrosion resistance of its own: shot-peen springs then phosphate + oil, powder coat or paint; avoid acid pickling and electroplating on hardened parts unless baked to relieve hydrogen.
SUP10 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 |
|---|---|---|
| CJIS G4801 SUP10 | 0.47 – 0.55 | 0.51 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.65 – 0.95 | 0.8 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 0.8 – 1.1 | 0.95 |
| Vgrain refinement, relaxation resistance | 0.15 – 0.25 | 0.2 |
| Cu | ≤ 0.3 | — |
| Fe | balance | — |
SUP10 Annealed — frequently asked
What is SUP10 Annealed used for?
SUP10 Annealed is typically used for coil springs, leaf springs and springs. In short: heavy-duty spring bar.
What is the yield strength of SUP10 Annealed?
SUP10 Annealed has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 60% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is SUP10 Annealed easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed condition (~55 % of 1212) with rigid setups and carbide at moderate speed; above 40 HRC switch to grinding, CBN or EDM.
Can SUP10 Annealed be welded?
Not readily — weldability is rated poor (25/100). Effectively not weldable in the hardened state — high carbon equivalent causes cracking; if unavoidable, preheat 300–350 °C, low-hydrogen consumables and re-quench/temper the whole part.
What surface finishes work on SUP10 Annealed?
No corrosion resistance of its own: shot-peen springs then phosphate + oil, powder coat or paint; avoid acid pickling and electroplating on hardened parts unless baked to relieve hydrogen.
Can SUP10 Annealed be formed, bent or molded?
Cold form or coil only when annealed or as oil-tempered wire; hot forge 1050–1150 °C, finish above 900 °C, slow cool, then harden from 830–870 °C in oil and temper 400–500 °C.
What is the maximum service temperature of SUP10 Annealed?
SUP10 Annealed 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.
Can FabDigit make parts in SUP10 Annealed?
Yes — SUP10 Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- JIS G 4801 Spring steels — Japanese Standards Association (2021)
- GB/T 1222 (50CrVA) — SAC (2016)
- SAE J404 / ASTM A231 (6150 Cr-V spring steel) — SAE / ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Machinery's Handbook (machinability ratings, spring design) — Industrial Press (2020)
- Mysteel / 1688 spring steel bar spot quotations (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.