A silicon-manganese spring steel (AISI 9260) with about 2% silicon. The high silicon lifts the elastic limit and resists settling, so 9260 is a favourite for large leaf and coil springs where a strong, fatigue-resistant spring is needed at modest cost.
What Is 9260 Spring Steel?
9260 is a high-silicon manganese spring steel. The ~2% silicon is the key: it raises the elastic limit, flattens the stress-strain curve and improves resistance to relaxation, so springs hold their set better than plain carbon grades.
It is widely used for automotive and heavy leaf springs and for large coil springs. It is not stainless and is not a high-temperature grade — for warm engine springs, a chromium-vanadium grade such as 50CrV4 is the better choice.
Supply Forms and Sizes
Every form is available soft-annealed (for further forming and machining) or heat-treated to your hardness window.
| Form | Condition | Size Range | Typical Use |
|---|---|---|---|
| Hot-rolled plate | Hot rolled / normalized | 3 – 50 mm | Leaf springs, blades |
| Hot-rolled bar | Hot rolled / cold drawn | 10 – 120 mm | Coil springs, forgings |
| Hardened & tempered strip | Q&T | 0.5 – 8 mm | Flat springs, washers |
| Cold-drawn wire | Annealed / oil-tempered | 1 – 14 mm | Coil springs |
Chemical Composition (AISI 9260)
| C | Si | Mn | Cr max | Ni max | P max | S max |
|---|---|---|---|---|---|---|
| 0.56 – 0.64 | 1.80 – 2.20 | 0.75 – 1.00 | 0.35 | 0.35 | 0.035 | 0.040 |
Heat analysis is reported on the mill certificate for every lot. If your drawing calls for tighter limits than the standard, flag it at enquiry — ladle-refined heats usually meet it without a surcharge.
Physical Properties
| Property | Value |
|---|---|
| Density | 7.85 g/cm³ |
| Elastic modulus (E) | ~200 GPa |
| Shear modulus (G) | ~79 GPa |
| Thermal conductivity | ~40 W/m·K at room temperature |
| Coefficient of thermal expansion | ~12 ×10⁻₆ /K (20 – 200 °C) |
Mechanical Properties
Typical values for 9260 after oil quenching and tempering near 460 °C. The mill certificate is the binding document.
| Condition | Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|---|
| Hot rolled, annealed | ≥ 980 MPa | ≥ 830 MPa | ≥ 11 % | ≤ 321 HB |
| Q&T | 1180 – 1420 MPa | ≥ 1030 MPa | ≥ 9 % | 40 – 48 HRC |
| Oil-tempered wire | 1500 – 1900 MPa | — | — | per size class |
Equivalent Grades
| Standard | Designation |
|---|---|
| USA AISI / SAE | 9260 |
| Europe EN | 55Si7 (similar) |
| China GB/T 1222 | 60Si2MnA (similar) |
| Japan JIS G4801 | SUP7 (similar) |
Heat Treatment and Processing
Preheat slowly, then raise to the grade forging range. Work above the lower limit and cool slowly after forging to avoid cracks.
780 – 840 °C, soak, furnace cool. Soft condition for forming and coiling.
840 – 870 °C, oil. The high Si needs care on decarburisation control.
400 – 520 °C by required hardness; ~460 °C gives the usual 44 – 48 HRC spring window.
After machining or forming, 200 – 350 °C for 1 – 2 hours, air cool, to stabilise dimensions and relieve residual stress.
Heat-treated bars and plates are supplied with the hardness and test certificate you specify. For critical parts we can control decarburisation depth and supply a spheroidized or soft-annealed structure on request.
Applications of 9260 Spring Steel
The classic use; high Si keeps the spring set under load.
Suspension and buffer springs for commercial vehicles.
Tines, sweeps and linkage springs in heavy duty.
Hardened-and-tempered strip at 44 – 48 HRC.
From 9260 bar for high-load machined springs.
Good edge and toughness for band tools.
9260 Spring Steel vs Alternative Grades
| Grade | vs 9260 Spring Steel | Choose It When |
|---|---|---|
| 9260 | — | Large leaf/coil springs where cost and elastic limit matter. |
| 65Mn | Cheaper, lower Si | Light strip and wire springs |
| 50CrV4 | Cr+V for fatigue and temper | High-cycle or warm engine springs |
| SUP9 / 55Cr3 | Higher hardenability | Thick leaf plate needing oil through-hardening |
Quality Control and Mill Certificates
Every shipment ships with an EN 10204 3.1 mill certificate covering heat chemical analysis, hardness and the mechanical test on record. On request we add: ultrasonic test on heavy bar and plate, magnetic particle inspection on machined surfaces, and third-party inspection (SGS / BV) before loading. Dimensional tolerances follow the relevant EN / ASTM / JIS standard or your drawing.
Frequently Asked Questions
What is 9260 equivalent to?
Closest are European 55Si7, China 60Si2MnA and Japanese SUP7. Confirm against the certificate for critical parts.
What is special about 9260 spring steel?
The ~2% silicon raises the elastic limit and resistance to set, so springs stay strong and keep their shape better than plain carbon grades.
What hardness does 9260 reach?
Typically 40 – 48 HRC in the quenched-and-tempered spring condition.
Does 9260 rust?
It is not stainless; keep it oiled or coated in humid or outdoor service.
What is the minimum order quantity?
Mill lots typically start at 500 kg per item; trial bar and plate are often from stock.
Related Products
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