C80 vs C75: Adjacent carbon grades — C80 marginally harder
C80 vs C75
Side-by-side chemical composition and mechanical property comparison.
Overview
C80
1.0609
Highest-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.
C75
1.0605
High-carbon unalloyed spring steel. Near-eutectoid composition (0.70-0.80% C). Excellent elastic properties after hardening and tempering. Limited hardenability — effective oil quench diameter ≤12mm. Cost-effective for small/medium springs. Used for spring wire, clock springs, saw blades, retaining rings, and precision strip springs. ≈ AISI 1075.
| C80 | C75 | |
|---|---|---|
| Material Number | 1.0609 | 1.0605 |
| Category | Carbon Steel | Carbon Steel |
| Standard | EN 10132-4 | EN 10132-4 |
Chemical composition (wt%)
| Element | C80 | C75 | Overlap |
|---|---|---|---|
| C | 0.75–0.85% | 0.7–0.8% | Partial |
| Si | 0.15–0.4% | 0.15–0.35% | OK |
| Mn | 0.6–0.9% | 0.6–0.9% | OK |
| P | 0–0.025% | 0–0.025% | OK |
Mechanical properties
| Property | C80 | C75 | Unit |
|---|---|---|---|
| tensile_strength | 900–1200 | 850–1100 | MPa |
| yield_strength | 550–750 | 500–700 | MPa |
| elongation | 6–10 | 8–12 | % |
Compatibility Assessment
C80 has 0.75-0.85% C vs 0.70-0.80% for C75. Slightly harder as-quenched (61 vs 60 HRC typical) but more brittle. Near-identical in most spring applications. Choose C80 for maximum hardness (saw blades); C75 where slightly better toughness matters.
Frequently Asked Questions
Is C80 the same as C75?
C80 and C75 have a 92% composition overlap. Adjacent carbon grades — C80 marginally harder
Can I replace C80 with C75?
In many cases, yes. The compositions overlap significantly (92%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between C80 and C75?
The main differences are in the following elements: C. C80 is a Carbon Steel grade, while C75 is a Carbon Steel grade.
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.