Steel 51CrV4 · temper · default condition
Steel 51CrV4 Annealed
Properties of the Annealed condition, compared with the other 51CrV4 tempers.
Standard stock condition for bar and strip that will be machined or formed and then hardened by the customer.
What is 51CrV4 Annealed?
51CrV4 Annealed is 51CrV4 in the Annealed temper — standard stock condition for bar and strip that will be machined or formed and then hardened by the customer. 51CrV4 Annealed 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). 51CrV4 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).
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
- Low electrical conductivity — 6.9 % IACS, worse than 76% of steel grades
51CrV4 Annealed properties
Typical room-temperature values for 51CrV4 Annealed — 12 properties are specific to this condition; the rest are grade-level values shared by every 51CrV4 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
51CrV4 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).
Mechanical13
51CrV4 Annealed 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 Annealed 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 Annealed 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 Annealed 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 Annealed'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.
Other 51CrV4 tempers and conditions
51CrV4 is also supplied in 9 other conditions. The full side-by-side table is on the 51CrV4 overview.
- AnnealedDefaultStandard stock condition for bar and strip that will be machined or formed and then hardened by the customer.520 MPa yield · 230 HB
- Hardened & TemperedFull spring hardness for leaf springs, saw/knife blades and hand tools where maximum elastic limit is needed and ductility can be sacrificed.1,500 MPa yield · 50 HRC
- Q&TBest strength/toughness compromise for torsion bars, coil springs and highly loaded machine parts.1,150 MPa yield · 42 HRC
- +CHBar/rod delivered heat-treated to a specified core-strength (core hardness) band, giving uniform mid-range strength and good machinability before final hardening.460 MPa yield · 210 HB
- +SSoftened delivery condition with hardness held below a set ceiling so bar and wire can be cold-sheared or cropped cleanly without cracking.430 MPa yield · 215 HB
- +ACLong sub-critical anneal that rounds the carbides into globular form, giving the lowest hardness and best cold-forming/machining behaviour of this grade.380 MPa yield · 190 HB
Working with 51CrV4 Annealed
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.
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.
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 | — |
51CrV4 Annealed — frequently asked
What is 51CrV4 Annealed used for?
51CrV4 Annealed is typically used for leaf springs, coil springs and springs. In short: vanadium chromium spring bar.
What is the yield strength of 51CrV4 Annealed?
51CrV4 Annealed 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 10 listed tempers.
Is 51CrV4 Annealed 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 Annealed 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 Annealed?
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 Annealed 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 Annealed?
51CrV4 Annealed 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.
Can FabDigit make parts in 51CrV4 Annealed?
Yes — 51CrV4 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
- 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.