Spring steel wire is drawn to tight diameters for coil, valve, torsion and flat springs. We supply it in plain-carbon and alloy grades, annealed, cold-drawn or oil-tempered, to EN, ASTM and JIS tolerances.
What Is Spring Steel Wire?
Spring steel wire is cold-drawn from rod that has been patenting- or oil-hardened, then drawn through dies to the finished diameter with closely controlled tolerance and surface. The result is a material that can be coiled, formed and finally heat-treated into a spring with a predictable set and fatigue life.
We supply it across the common spring grades — from economical 65Mn through chromium-vanadium 50CrV4 / 6150 to silicon-manganese 9260 and SUP9 — in the condition your process needs: soft-annealed for forming, cold-drawn (hard) for direct coiling, or pre-oil-tempered so the spring is ready after coiling.
Spring Steel Grades Available as Wire
The grade sets the fatigue strength, temper resistance and cost of the finished spring. We keep the following spring grades available as wire and draw to your diameter:
| Grade | Standard | Typical Use |
|---|---|---|
| 65Mn | GB/T 4357, GB/T 1222 | Light coil & flat springs, clips, washers |
| 50CrV4 / 51CrV4 | EN 10270-2 (1.8159) | Engine valve springs, heavy coils, warm service |
| 6150 | ASTM A229 / A401 | Valve & torsion springs (North America) |
| SUP9 / 55Cr3 | JIS G3521, EN 10089 | Heavy leaf and coil springs |
| 9260 | ASTM A229 | Large leaf, buffer and suspension springs |
Size Range and Tolerances
We draw wire from fine 0.2 mm music-grade diameters up to 20 mm spring wire. Tighter tolerance classes are offered for critical coilers; ask for the class you need:
| Diameter Range | Tolerance Class | Condition | Coil / Pack |
|---|---|---|---|
| 0.2 – 1.0 mm | EN 10270 h9 / custom | Annealed or oil-tempered | Spools, 100 – 300 kg |
| 1.0 – 6.0 mm | EN 10270 h10 / h11 | Cold-drawn or oil-tempered | Spools or carriers, 250 – 500 kg |
| 6.0 – 12 mm | h11 / drawn | Annealed or oil-tempered | Carriers, 500 – 1000 kg |
| 12 – 20 mm | peeled / drawn | Annealed | Bundles, per order |
Surface Finish and Delivery Condition
Spring wire is supplied in several conditions. The right one depends on whether you will form the spring yourself or buy it pre-set:
Full-annealed wire for you to form and heat-treat after coiling. Easiest to bend, lowest residual stress.
Drawn to high strength for direct coiling of light springs; springs are then stress-relieved.
Pre-quenched and tempered to a set tensile range, so the spring is largely finished after coiling and a short stress relief.
Zinc, phosphate or copper coating on request for corrosion resistance or drawing lubrication.
Standards We Supply To
| Standard | Scope |
|---|---|
| EN 10270-1 | Patented cold-drawn unalloyed spring steel wire |
| EN 10270-2 | Oil-tempered valve spring wire (incl. 50CrV4 / 51CrV4) |
| EN 10270-3 | Stainless spring wire (on request) |
| ASTM A229 | Carbon steel spring wire (oil-tempered) |
| ASTM A401 | Chromium-silicon valve spring wire |
| JIS G3521 / G3522 | Hard-drawn / oil-tempered spring wire |
Physical Properties of Spring Steel
| Property | Typical Value |
|---|---|
| Density | 7.85 g/cm³ |
| Elastic modulus (E) | ~200 GPa |
| Shear modulus (G) | ~79 GPa |
| Thermal conductivity | ~45 W/m·K at room temperature |
| Coefficient of thermal expansion | ~12 ×10⁻₆ /K (20 – 200 °C) |
Applications of Spring Steel Wire
The most demanding use — high-cycle life at temperature, usually oil-tempered Cr-V wire.
From small appliance springs to heavy suspension coils.
Ductile conditions let the wire be bent into hooks and legs.
Fatigue resistance under continuous load.
Flattened or shaped from round wire.
Spring wire drawn to the sections used for snap rings.
Quality Control and Mill Certificates
Every Wire order ships with an EN 10204 3.1 mill certificate covering heat chemical analysis and the mechanical and dimensional checks on record. We add, on request: ultrasonic or magnetic-particle inspection, hardness mapping, straightness and flatness checks, decarburisation or surface-depth checks, and third-party inspection (SGS / BV) at the mill or before loading. Dimensions are verified to the relevant EN / ASTM / JIS standard or your drawing.
Frequently Asked Questions
What grades of spring steel wire do you supply?
From plain-carbon 65Mn up to chromium-vanadium 50CrV4 / 6150, silicon-manganese 9260 and SUP9. We draw to your diameter and condition.
What does oil-tempered wire mean?
The wire is quenched and tempered before shipping, so after you coil and stress-relieve it, the spring is essentially finished — no separate hardening step.
What diameter tolerance can you hold?
Typically EN 10270 h9–h11 depending on diameter; tighter classes are available for critical coilers.
Can you supply valve-spring-quality wire?
Yes. Oil-tempered 50CrV4 / 51CrV4 and 6150 to EN 10270-2 / ASTM A401, with surface and decarburisation inspection on request.
What is the minimum order quantity?
Spooled wire often starts around 300 kg per diameter/grade; carriers and bundles are quoted per order.
Related Products
Send your size, grade, delivery condition, quantity, package and destination port. You will get a firm price and lead time within one working day.
