55
Data verified55 is the GB/T 699 equivalent of AISI 1055 / JIS S55C, bridging machinery and spring applications with plain-carbon economics.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.52–0.60 |
| Si | 0.17–0.37 |
| Mn | 0.50–0.80 |
| P | ≤0.035 |
| S | ≤0.035 |
| Cr | ≤0.25 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Tensile strength | ≥645 MPa (GB/T 699 reference, normalized blank) |
| Yield strength | ≥380 MPa (reference) |
| Density | 7.85 g/cm³ |
Heat treatment
Quench and temper in moderate sections; induction hardening widely used.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.0535 (C55) |
| aisi | 1055 |
| jis | S55C |
| gb | 55 (GB/T 699) |
Compare side by side: 55 vs 1055
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Leaf and coil springs (light), shafts, wear parts, agricultural tools.
Processing: Limited weldability; machines acceptably in the annealed/normalized condition.
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Ask for a quotationVisit NasteelSource: GB/T 699-2015 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.