C80
1.0609Highest-carbon standard unalloyed spring steel. 0.75-0.85% C gives maximum hardness (60+ HRC) among unalloyed grades but with increased brittleness. Limited hardenability — effective quench diameter ≤10mm. Used for high-hardness springs, saw blades, scrapers, and precision strip where maximum elastic limit is needed. ≈ AISI 1080.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | AISI | USA | AISI 1080 | — | REF |
| 🇪🇺 | EN | Europe | C80 / C80S | 1.0609 | 100% |
Sources: ASTM A29, EN 10132-4
Chemical composition comparison (wt%)
Side-by-side: C80 (EN 10132-4) vs C80 / C80S (EN) (EN 10132-4)
| Element | C80 (EN 10132-4) | C80 / C80S (EN) | Overlap |
|---|---|---|---|
| C | — | 0.75–0.85% | — |
| Si | — | 0.15–0.4% | — |
Mechanical properties
Compatibility verdict
C80 and C80 / C80S: 100% composition match
Related materials
C45
1.0503Medium carbon unalloyed quality steel. Good machinability and moderate strength after heat treatment. Widely used for shafts, spindles, pins, studs, and general machine parts.
S355JR
1.0045High-strength low-alloy structural steel with minimum yield strength of 355 MPa. Standard grade for bridges, buildings, cranes, and general structural applications. Impact tested at +20°C (JR).
S235JR
1.0038General-purpose structural steel with minimum yield strength of 235 MPa. The most common structural steel grade in Europe for general construction, frames, and non-critical structural applications.
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