9255
Data under review9255 is a Si-Cr spring steel combining the sag resistance of silicon with chromium hardenability. It serves coil and leaf springs that are too thick for plain Si-Mn grades to harden through.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.51–0.59 |
| Si | 1.20–1.60 |
| Mn | 0.70–0.90 |
| Cr | 0.70–0.90 |
| P | ≤0.035 |
| S | ≤0.040 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Hardness (spring temper) | 40–48 HRC typical |
| Tensile strength | 1200–1500 MPa (Q&T spring temper, typ.) |
| Density | 7.85 g/cm³ |
Heat treatment
Anneal 830–860 °C; quench 850–880 °C oil; temper 400–500 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.5026 (55Si7 family, near) |
| aisi | 9255 |
| jis | SUP7 (near) |
| gb | 55Si2Mn (near) |
Compare side by side: 9255 vs 5160 · 9255 vs 9260
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Coil springs, leaf springs, torsion bars for vehicles and machinery.
Processing: Watch decarburization as with all high-silicon steels; oil quench standard.
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Ask for a quotationVisit NasteelSource: SAE J404 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.