Steel FDSiCrV
FDSiCrV is a silicon-chromium-vanadium alloyed, oil-tempered spring steel wire and the highest-alloyed variant of the FD wire series, intended for the most demanding high-stress springs.
Reference datasheet — FDSiCrV is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the OT condition
FDSiCrV tempers and conditions
FDSiCrV is supplied in 8 conditions, soft to hard. OT 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 |
|---|---|---|---|---|---|---|
OT | Largest supplied sizes for very heavy static springs; hardenability limits the achievable strength. | 1,440 | 1,620 | 8 | 47 HRC | 6.9 % IACS |
OT | Heavy springs (clutch, suspension aids) where load capacity matters more than peak tensile. | 1,530 | 1,720 | 8 | 49 HRC | 6.9 % IACS |
OT | Mid-heavy spring sizes; tensile level drops slightly with section. | 1,630 | 1,830 | 7 | 51 HRC | 6.9 % IACS |
OTDefault Oil hardened and tempered, d 2.0–4.0 mm | Standard stocked condition: quenched-and-tempered wire in the most common spring diameters, coiled cold by the spring maker. | 1,720 | 1,930 | 6 | 53 HRC | 6.9 % IACS |
coiled then stress-relieved 380–420 °C | Condition of the finished spring: stress relief after coiling restores elastic limit, sets free length and lowers relaxation. | 1,780 | 1,900 | 6 | 52 HRC | 6.9 % IACS |
OT + SR + shot peened spring | Choose when the static-grade wire must still see load cycling: peening compressive layer lifts endurance markedly. | 1,780 | 1,900 | 6 | 53 HRC | 6.9 % IACS |
OT | Common size band for small compression and torsion springs. | 1,790 | 2,010 | 5.5 | 54 HRC | 6.9 % IACS |
OT fine wire | Pick for small high-stress springs; the finest sizes carry the highest tensile level of the grade. | 1,900 | 2,120 | 5 | 56 HRC | 6.9 % IACS |
Supply forms, finishes and certifications
Ways FDSiCrV is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
OT-PH | OT, phosphated + oiled wire surface | Surface finish |
OT-ZN | OT, zinc / Zn-Ni coated | Surface finish |
What is FDSiCrV?
FDSiCrV is a silicon-chromium-vanadium alloyed, oil-tempered spring steel wire and the highest-alloyed variant of the FD wire series, intended for the most demanding high-stress springs. It is supplied in diameter-banded OT conditions plus stress-relieved, shot-peened, phosphated and zinc-coated forms, with default values of 1720 MPa yield, 1930 MPa tensile, 6 % elongation, about 53 HRC and service to 250 °C. Cost and lead time are the highest in the family, it cannot carry welded joints in the tempered state, and it has no inherent corrosion resistance. FDSiCr (A401) covers the same applications at lower design stress. FDSiCrV 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). FDSiCrV has a yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,930 MPa (280 ksi) — stronger than 99% of steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi).
What is FDSiCrV used for?
- high-performance valve springs
- critical fatigue-loaded springs
- high-temperature service springs
Advantages
- High strength — 1,720 MPa (249 ksi), better than 99% of steel grades
Limitations
- Limited ductility — 6%, worse than 97% of steel grades
- Difficult to machine — 20/100, worse than 97% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Low fracture toughness — 35 MPa·√m (31.9 ksi·√in), worse than 94% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
FDSiCrV properties
Typical room-temperature values for FDSiCrV-OT; bars are the position among steel grades.
Physical3
FDSiCrV 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).
Mechanical16
FDSiCrV has a yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,930 MPa (280 ksi) — stronger than 99% of steel grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
FDSiCrV is rated for continuous service to 250°C (482 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), worse than 83% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
FDSiCrV 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 FDSiCrV takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability6
FDSiCrV's machinability is poor (20/100, worse than 97% of steel grades); weldability not recommended (12/100); formability poor (25/100).
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. FDSiCrV is highlighted; hover a dot for its name, or open the interactive family chart.
Working with FDSiCrV
Is FDSiCrV easy to machine?
Delivered at ~50-55 HRC — do not turn or drill; finish springs by grinding ends and tumbling, or machine features before any thermal work.
Can FDSiCrV be welded?
Effectively unweldable for load-carrying joints: high carbon plus Si-Cr-V gives hard, crack-prone HAZ and destroys the tempered structure; use mechanical hooks or captive ends instead.
Can FDSiCrV be formed, bent or molded?
Cold-coil on CNC formers with generous mandrel ratio (D/d ≥ 4) and good lubricity (phosphated wire); always stress relieve 380–420 °C for 20–30 min after coiling, then optionally hot-set and shot peen.
FDSiCrV 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 | 0.51 – 0.59 | 0.55 |
| Siraises elastic limit and relaxation resistance | 1.2 – 1.6 | 1.4 |
| Mn | 0.5 – 0.8 | 0.65 |
| Crhardenability | 0.5 – 0.8 | 0.65 |
| Vgrain refinement, temper resistance | 0.1 – 0.2 | 0.15 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Cumax, residual | ≤ 0.12 | |
| Fe | balance |
What surface finishes work on FDSiCrV?
Phosphate+oil for storage; for service use zinc, Zn-Ni or Zn-flake/epoxy coating — after acid pickling or electroplating bake 190–220 °C to relieve hydrogen and avoid delayed fracture.
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).
Organic Coating
Black / Phosphate
Thermal Spray
How much does FDSiCrV cost?
FDSiCrV 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.
FDSiCrV — frequently asked
What is FDSiCrV used for?
FDSiCrV is typically used for high-performance valve springs, critical fatigue-loaded springs and high-temperature service springs. In short: highest-strength FD spring wire; maximum design-stress springs; si-Cr-V alloyed, oil-tempered.
What is the yield strength of FDSiCrV?
FDSiCrV has a typical yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,930 MPa (280 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is FDSiCrV easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Delivered at ~50-55 HRC — do not turn or drill; finish springs by grinding ends and tumbling, or machine features before any thermal work.
Can FDSiCrV be welded?
Not readily — weldability is rated not recommended (12/100). Effectively unweldable for load-carrying joints: high carbon plus Si-Cr-V gives hard, crack-prone HAZ and destroys the tempered structure; use mechanical hooks or captive ends instead.
What surface finishes work on FDSiCrV?
Phosphate+oil for storage; for service use zinc, Zn-Ni or Zn-flake/epoxy coating — after acid pickling or electroplating bake 190–220 °C to relieve hydrogen and avoid delayed fracture.
Can FDSiCrV be formed, bent or molded?
Cold-coil on CNC formers with generous mandrel ratio (D/d ≥ 4) and good lubricity (phosphated wire); always stress relieve 380–420 °C for 20–30 min after coiling, then optionally hot-set and shot peen.
What is the maximum service temperature of FDSiCrV?
FDSiCrV 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.
What is the difference between FDSiCrV-OT and FDSiCrV OT-SR?
OT is the default condition — standard stocked condition: quenched-and-tempered wire in the most common spring diameters, coiled cold by the spring maker. OT-SR: condition of the finished spring: stress relief after coiling restores elastic limit, sets free length and lowers relaxation. Yield strength is 1,720 MPa in OT versus 1,780 MPa in OT-SR.
How much does FDSiCrV cost?
FDSiCrV 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.
Sources
- EN 10270-2 Steel wire for mechanical springs — Part 2: Oil hardened and tempered spring steel wire — CEN (2012)
- EN 13906-1 Cylindrical helical springs — compression springs design — CEN (2013)
- EN ISO 683-14 / 54SiCrV6 spring steel chemistry — ISO (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels (spring steels) — ASM International (1990)
- Oil tempered Si-Cr and Si-Cr-V spring wire datasheets — Kanthal Garphyttan / Suzuki Garphyttan (2022)
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.