Steel 51CrV4
EN 51CrV4 · UNS G61500 · AISI/SAE 6150 · JIS SUP10 · GB 50CrVA
51CrV4 (1.8159) is a chromium-vanadium spring steel to EN 10083/10089, the European counterpart of AISI 6150 (G61500) and also listed as 50CrV4, 50CrVA and SUP10, with a high elastic limit and high fatigue strength.
Values for the Annealed condition
51CrV4 tempers and conditions
51CrV4 is supplied in 8 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Long sub-critical anneal that rounds the carbides into globular form, giving the lowest hardness and best cold-forming/machining behaviour of this grade. | 380 | 640 | 22 | 190 HB | 46 W/m·K |
High Shearability | Softened delivery condition with hardness held below a set ceiling so bar and wire can be cold-sheared or cropped cleanly without cracking. | 430 | 700 | 18 | 215 HB | 45 W/m·K |
Core Hardened | Bar/rod delivered heat-treated to a specified core-strength (core hardness) band, giving uniform mid-range strength and good machinability before final hardening. | 460 | 720 | 16 | 210 HB | 44 W/m·K |
AnnealedDefault max 248 HB | Standard stock condition for bar and strip that will be machined or formed and then hardened by the customer. | 520 | 800 | 15 | 230 HB | — |
as-rolled bar / flat | Cheapest mill condition for leaf-spring flats and forging stock; scale and decarburised skin must be removed before hardening. | 600 | 950 | 12 | 29 HRC | 6.9 % IACS |
air cooled from ~860 °C | Used to homogenise forgings and refine grain before machining or final hardening. | 650 | 1,000 | 12 | 31 HRC | 6.9 % IACS |
cold drawn / peeled bar | Bright, close-tolerance bar for torsion bars and shafting where light machining follows; residual stress must be considered. | 800 | 950 | 8 | 30 HRC | 6.8 % IACS |
spring temper, tempered ~400–430 °C (≈48–52 HRC) | Full spring hardness for leaf springs, saw/knife blades and hand tools where maximum elastic limit is needed and ductility can be sacrificed. | 1,500 | 1,700 | 6 | 50 HRC | — |
Supply forms, finishes and certifications
Ways 51CrV4 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 Hardened Spring Wire | FDCrV / oil hardened & tempered spring wire | Supply form |
What is 51CrV4?
51CrV4 (1.8159) is a chromium-vanadium spring steel to EN 10083/10089, the European counterpart of AISI 6150 (G61500) and also listed as 50CrV4, 50CrVA and SUP10, with a high elastic limit and high fatigue strength. It is used for leaf and coil springs and torsion bars, and is available annealed, hot-rolled, normalized, cold-drawn, quenched and tempered and as oil-hardened spring wire, at about 520 MPa yield, 800 MPa tensile, 15 % elongation and 230 HB with service to 250 °C. Weldability is poor at this carbon level, there is no corrosion resistance, and machinability is only about 48. 51CrV4 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). 51CrV4 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
What is 51CrV4 used for?
- Leaf springs
- Coil springs
- Springs
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
51CrV4 properties
Typical room-temperature values for 51CrV4-Annealed; bars are the position among steel grades.
Physical3
51CrV4 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).
Mechanical13
51CrV4 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Elongation at break is 15% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
51CrV4 is rated for continuous service to 250°C (482 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
51CrV4 conducts electricity at 6.9 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 51CrV4 takes about 32 MJ of energy and emits 2.1 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
51CrV4's machinability is fair (48/100, worse than 57% of steel grades); weldability poor (25/100); formability fair (45/100).
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. 51CrV4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 51CrV4
Is 51CrV4 easy to machine?
Machine in the annealed condition (≈55 % of 1212) with rigid setups and carbide tooling; above 40 HRC switch to CBN/ceramic or grinding.
Can 51CrV4 be welded?
Poor weldability at 0.5 % C — preheat 250–350 °C, low-hydrogen consumables and immediate post-weld temper; avoid welding on finished springs.
Can 51CrV4 be formed, bent or molded?
Cold form or coil only in the annealed/soft state (bend radii ≥3 t), then austenitise 840–870 °C, oil quench and temper 400–520 °C; hot form 850–1050 °C.
Manufacturability
The process limits FabDigit applies to 51CrV4. Every 51CrV4 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair48 / 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 | Better45 / 100 |
|---|---|
| Weldability | Fair25 / 100 |
| Bendable | Yes |
51CrV4 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 |
|---|---|---|
| C | 0.47 – 0.55 | 0.51 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.7 – 1.1 | 0.9 |
| Cr | 0.9 – 1.2 | 1.05 |
| Vgrain refinement, secondary carbides | 0.1 – 0.25 | 0.15 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on 51CrV4?
Not anodisable; shot-peen springs for fatigue life, then phosphate + epoxy, zinc or Zn-Ni plating with bake-out at 200 °C to avoid hydrogen embrittlement.
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 51CrV4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 51CrV4 cost?
51CrV4 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
51CrV4 — frequently asked
What is 51CrV4 used for?
51CrV4 is typically used for leaf springs, coil springs and springs. In short: vanadium chromium spring bar.
What is the yield strength of 51CrV4?
51CrV4 has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 51CrV4 easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machine in the annealed condition (≈55 % of 1212) with rigid setups and carbide tooling; above 40 HRC switch to CBN/ceramic or grinding.
Can 51CrV4 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability at 0.5 % C — preheat 250–350 °C, low-hydrogen consumables and immediate post-weld temper; avoid welding on finished springs.
What surface finishes work on 51CrV4?
Not anodisable; shot-peen springs for fatigue life, then phosphate + epoxy, zinc or Zn-Ni plating with bake-out at 200 °C to avoid hydrogen embrittlement.
Can 51CrV4 be formed, bent or molded?
Cold form or coil only in the annealed/soft state (bend radii ≥3 t), then austenitise 840–870 °C, oil quench and temper 400–520 °C; hot form 850–1050 °C.
What is the maximum service temperature of 51CrV4?
51CrV4 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 51CrV4 cost?
51CrV4 is a standard-cost steel ($$), 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 51CrV4?
Yes — 51CrV4 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
- EN 10089 — Hot rolled steels for quenched and tempered springs — CEN (2002)
- EN 10270-2 — Steel wire for mechanical springs: oil hardened and tempered — CEN (2011)
- GB/T 1222 — (50CrVA) — SAC (2016)
- SAE J404 / ASTM A231 (AISI 6150 Cr-V spring steel) — SAE / ASTM (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Cr-V spring steel 1.8159 datasheet — Böhler / Ovako / Saarstahl (2022)
- EN 13906-1 — Cylindrical helical springs, design — CEN (2013)
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.