Steel SUP10
GB SUP10 · AISI/SAE 6150 · EN 50CrV4, 50CrVA
SUP10 is a chromium-vanadium spring steel comparable to 51CrV4 and 50CrV4 (AISI 6150), where the vanadium addition refines grain and supports high fatigue strength.
Values for the Annealed condition
SUP10 tempers and conditions
SUP10 is supplied in 6 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft/spheroidize annealed bar and coil for machining and forming | Stock condition for machining, cold forming and pre-heat-treat blanks before quench and temper. | 480 | 780 | 20 | 210 HB | — |
as-rolled bar, flat and coil | Cheapest mill condition for leaf-spring flats and forging stock that will be heat treated later. | 560 | 900 | 14 | 25 HRC | 7.5 % IACS |
austenitised and air cooled, refined grain | Use to homogenise forgings and refine grain before hardening, or where moderate strength suffices. | 660 | 1,000 | 13 | 31 HRC | 7.5 % IACS |
cold drawn / peeled-ground annealed bar and wire | Choose for close-tolerance bar, torsion-bar and wire blanks needing good surface before hardening. | 800 | 950 | 9 | 28 HRC | 7.4 % IACS |
Higher-temper condition for toughness-critical torsion bars and… | Use where fatigue with impact loading matters more than peak stress (stabiliser bars, heavy leaf springs). | 1,120 | 1,250 | 11 | 40 HRC | 7.2 % IACS |
Quenched and tempered | Standard spring condition: highest usable strength with adequate toughness for leaf, coil and torsion springs. | 1,300 | 1,450 | 9 | 44 HRC | — |
Supply forms, finishes and certifications
Ways SUP10 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Oil Tempered Wire | Continuously oil hardened-and-tempered Cr-V spring wire | Supply form |
What is SUP10?
SUP10 is a chromium-vanadium spring steel comparable to 51CrV4 and 50CrV4 (AISI 6150), where the vanadium addition refines grain and supports high fatigue strength. It is supplied as hot-rolled, annealed and cold-drawn bar, flat and oil-tempered wire for high-stress automotive coil springs, torsion bars and leaf springs; the annealed default condition is 480 MPa yield, 780 MPa tensile, 20 % elongation and about 210 HB, with Q&T tempers to 38–42 HRC. It has no corrosion resistance, is effectively unweldable once hardened, and must be quenched and tempered after forming. 51CrV4 bar is the direct equivalent when JIS stock is unavailable. SUP10 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). SUP10 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 59% of steel grades. Elongation at break is 20% and the elastic modulus is 206 GPa (29.9 Msi).
What is SUP10 used for?
- Coil springs
- Leaf springs
- Springs
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 properties
Typical room-temperature values for SUP10-Annealed; bars are the position among steel grades.
Physical3
SUP10 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 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 59% of steel grades. Elongation at break is 20% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SUP10 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 conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SUP10 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
SUP10'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.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SUP10 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SUP10
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.
Manufacturability
The process limits FabDigit applies to SUP10. Every SUP10 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair55 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better40 / 100 |
|---|---|
| Weldability | Fair25 / 100 |
| Bendable | Yes |
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SUP10 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does SUP10 cost?
SUP10 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SUP10 — frequently asked
What is SUP10 used for?
SUP10 is typically used for coil springs, leaf springs and springs. In short: heavy-duty spring bar.
What is the yield strength of SUP10?
SUP10 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is SUP10 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed condition (~55 % of 1212) with rigid setups and carbide at moderate speed; above 40 HRC switch to grinding, CBN or EDM.
Can SUP10 be welded?
Not readily — weldability is rated poor (25/100). Effectively not weldable in the hardened state — high carbon equivalent causes cracking; if unavoidable, preheat 300–350 °C, low-hydrogen consumables and re-quench/temper the whole part.
What surface finishes work on SUP10?
No corrosion resistance of its own: shot-peen springs then phosphate + oil, powder coat or paint; avoid acid pickling and electroplating on hardened parts unless baked to relieve hydrogen.
Can SUP10 be formed, bent or molded?
Cold form or coil only when annealed or as oil-tempered wire; hot forge 1050–1150 °C, finish above 900 °C, slow cool, then harden from 830–870 °C in oil and temper 400–500 °C.
What is the maximum service temperature of SUP10?
SUP10 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does SUP10 cost?
SUP10 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in SUP10?
Yes — SUP10 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 — 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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.