Chromium-vanadium alloy spring steel per EN 10089 — C 0.47–0.55%, Cr 0.90–1.20%, V 0.10–0.25%. Vanadium-refined grain delivers fatigue life above 1 million cycles for diaphragm springs, valve springs and suspension springs. Supplied spheroidized for blanking or quenched and tempered to finished properties.
50CrV4 is the step up from plain carbon spring steel when the part sees millions of load cycles, when the section is too thick for carbon steel to through-harden, or when operating temperatures approach the tempering range.
Plain carbon spring steels are lean and cost-effective for thin-strip flat springs, circlips and washers. 50CrV4 adds Cr and V for deeper hardening, higher fatigue strength and better toughness in heavier sections — the right call for high-cycle valve and suspension springs. Trade-off: material cost.
50CrV4 for high-cycle, heavy-section springs; C67S/C75S for thin-gauge, cost-sensitive parts.60Si2Mn (GB) is a silicon-manganese spring steel with higher Si for elevated elastic limit — common in Chinese automotive leaf spring specs. 50CrV4 offers better hardenability and fatigue resistance through the Cr-V combination, and is the more internationally recognized grade under EN and ISO. The choice often follows the equipment's original specification.
50CrV4 for EN/ISO-spec parts; 60Si2Mn for GB-spec leaf springs.51CrV4 is the same family with slightly higher carbon (0.49–0.57% vs. 0.47–0.55%) — the difference is marginal, and the two grades are often used interchangeably. 50CrV4 is more common in European spring steel strip; 51CrV4 appears more in bar and wire specs. Follow the grade on your drawing.
Near-identical; follow your drawing's specified grade.The chromium-vanadium combination defines 50CrV4. Cr provides hardenability; V refines grain. Actual heat chemistry confirmed on MTC.
| Element | 50CrV4 (%) | Role |
|---|---|---|
| Carbon (C) | 0.47 – 0.55 | Sets base hardness and strength after Q&T |
| Silicon (Si) | 0.15 – 0.40 | Deoxidizer; raises elastic limit and temper resistance |
| Manganese (Mn) | 0.70 – 1.10 | Hardenability |
| Chromium (Cr) | 0.90 – 1.20 | Deepens hardening; mild corrosion resistance |
| Vanadium (V) | 0.10 – 0.25 | Forms fine carbides; refines grain; boosts fatigue and toughness |
| Phosphorus (P) | ≤ 0.025 | Residual; controlled for fatigue |
| Sulfur (S) | ≤ 0.025 | Residual; controlled for fatigue and shear-face quality |
Reference: EN 10089 / ISO 683-14. Values typical per standard, actual confirmed on MTC. Compare with other spring grades in our spring steel standards comparison.
Supplied spheroidized for blanking and forming, or quenched-and-tempered for finished fatigue-grade spring properties.
| Condition | Hardness (typ.) | Tensile (typ.) | Yield (typ.) | Typical use |
|---|---|---|---|---|
| Spheroidized (soft annealed) | ≤ 225 HB | ~650 – 800 MPa | ~450 – 600 MPa | Blanking, forming, coiling — part quenched afterwards |
| Q&T (400–550°C temper) | 45 – 52 HRC | ≥ 1,500 MPa | ≥ 1,300 MPa | Diaphragm springs, valve springs, suspension springs |
Values per EN 10089 (sample ≤25 mm); actual confirmed on MTC. Fatigue strength (endurance limit) ~500–600 MPa for fully reversed bending in Q&T condition; shot peening raises this further. Thin strip through-hardens more readily than heavy sections.
Chemistry ranges overlap heavily — a single heat can often meet multiple specifications. Confirm against your governing standard before substitution.
| Standard | Grade | C (%) | Cr (%) | V (%) | Notes |
|---|---|---|---|---|---|
| EN 10089 | 50CrV4 (1.8159) | 0.47 – 0.55 | 0.90 – 1.20 | 0.10 – 0.25 | Base reference |
| GB/T 1222 | 50CrVA | 0.47 – 0.54 | 0.80 – 1.10 | 0.10 – 0.20 | Closest match; nearly identical |
| JIS G4801 | SUP10 | 0.47 – 0.55 | 0.90 – 1.20 | 0.10 – 0.25 | Identical chemistry |
| ASTM A231 / AISI | 6150 (approx.) | 0.48 – 0.53 | 0.80 – 1.10 | ≤ 0.15 | Lower V max; often wire form |
Equivalents approximate. For safety-critical parts, confirm full chemistry and inclusion rating against your governing spec and the MTC.
1.5–3.5 mm strip, blanked in spheroidized state, then Q&T to 46–50 HRC and shot-peened. The vanadium-refined grain gives the fatigue life needed for a clutch diaphragm that sees hundreds of thousands of engagement cycles. See our clutch disc spring guide.
50CrV4 wire/narrow strip, coiled and Q&T to 48–52 HRC, shot-peened and preset. High fatigue strength plus temper resistance makes it suitable for valve springs at continuous operating temperatures up to ~200°C. The V carbides resist over-aging during tempering.
3.0–8.0 mm bar/strip, formed into coil or leaf shapes, Q&T. Cr ensures through-hardening in heavier sections; V-refined grain provides fatigue resistance for millions of road-load cycles. Shot peening is standard for automotive suspension service.
0.3–2.0 mm strip, blanked or coiled into die springs, mold springs, fixture springs and conveyor springs. The ≥1M-cycle fatigue life means longer service intervals on production equipment compared to carbon spring steel alternatives. Supplied spheroidized for in-house coiling or H&T to finished hardness.
Exact parameters confirmed for your section size and target hardness.
Heat to 850–880°C, hold 15–30 min per 25 mm section. V carbides pin grain boundaries during this step, preventing grain growth and producing the fine grain that gives 50CrV4 its fatigue strength. Avoid overheating above 900°C.
Oil quench standard — Cr and Mo provide enough hardenability for through-hardening in sections up to ~100 mm. Thin strip (≤2 mm) may air-harden fully. Martempering used for large or thin-walled parts to minimize distortion.
Temper at 400–550°C for 1–2 hours. Mo suppresses temper embrittlement in the 400–550°C range, allowing high-temp temper for maximum toughness. High-strength parts (gears, shafts): 500–550°C → 35–40 HRC. High-toughness parts (bolts, rods): 600–650°C → 28–32 HRC.
For high-cycle springs, shot peening introduces compressive residual stress, raising fatigue limit by 20–30%. Presetting (scragging) stabilizes spring rate and prevents setting in service. Both standard for automotive valve and suspension springs.
Include thickness × width, quantity, condition (spheroidized or H&T) and destination port. Reply within one working day.