Spring steel
56Si7 / 1.5026 alloy engineering steel
56Si7 is silicon-alloyed spring steel and the family's workhorse in flat bar. EN 10089 calls it 56Si7, DIN 17221 called it 55Si7, and W.Nr. 1.5026 is the same in both. If the drawing says 55Si7, this is the grade.
- Delivery conditions
- untreated, soft annealed or +QT
- Also known as
- 1.5026, 55Si7
Designations
- W.Nr.
- 1.5026
- EN standard
- 56Si7
- DIN
- 55Si7
- Group
- Alloy engineering steel
What it is used for
Leaf springs, clamping bands, clips and hot-formed spring parts in flat bar.
Limits
Silicon is not chromium: the hardening depth follows the section. 51CrV4 or 52CrMoV4 when the material becomes heavy. 42CrMo4 when the job is a QT shaft and not a spring.
Delivery
We source 56Si7 from European mill partners as round bar, flat bar, square bar, cut to your dimensions and ship the certificate with the material. Typical condition: untreated, soft annealed or +QT. From a single cut piece to larger lots — with no minimum charge, so you do not have to buy a full commercial length to get what you need.
Certificates and documentation
56Si7 can be supplied with a material certificate to EN 10204, depending on producer, dimension and the requirements specified for the delivery. The heat and the delivery condition are what carry the certificate — a spring or bearing grade only gets its service properties after treatment, and that part is documented by whoever performs it. EN 10204 3.1 can be supplied on a wide range of our materials.
Dimension programme
| Form | Range | Note |
|---|---|---|
| Round bar | Ø2–35 mm drawn, Ø15–220 mm hot rolled, Ø230–710 mm forged | Drawn to DIN 671, hot rolled to DIN 1013, forged to DIN 7527. Bars in 3 or 6 m. State Ø and condition. |
| Flat bar | 20 × 3 mm to 200 × 20 mm | Flat spring steel in 5 or 6 m bars, cut to fixed length on request. Rounded edges or mill edge — state which. |
| Square bar | Same drawn and hot-rolled range as round | State side length and condition. Not every grade is run in square. |
The range is a delivery programme, not a stock statement. Length is cut to your drawing.
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Send your enquiry
State grade, dimensions and quantity — or attach a drawing. We reply with a quote.