C40
1.0511Medium-carbon unalloyed steel between C35 and C45 in properties. Good balance of strength and machinability. Used for moderately stressed machine parts, shafts, studs, axles, and crankshafts.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇺🇸 | AISI | USA | AISI 1040 | G10400 | REF |
| 🇪🇺 | EN | Europe | C40 | 1.0511 | 100% |
Sources: ASTM A29, EN 10083-2:2006
Chemical composition comparison (wt%)
Side-by-side: C40 (EN) (EN 10083-2:2006) vs C40 (EN) (EN 10083-2:2006)
| Element | C40 (EN) | C40 (EN) | Overlap |
|---|---|---|---|
| C | 0.37–0.44% | 0.37–0.44% | OK |
| Si | 0–0.4% | 0–0.4% | OK |
| Mn | 0.5–0.8% | 0.5–0.8% | OK |
| P | 0–0.03% | 0–0.03% | OK |
| S | 0–0.035% | 0–0.035% | OK |
Mechanical properties
Normalized
| Property | Value | Unit |
|---|---|---|
| Tensile Strength | 520–670 | MPa |
| Yield Strength | ≥ 305 | MPa |
| Elongation | ≥ 19 | % |
| Elastic Modulus | ≥ 210 | GPa |
| Density | ≥ 7.85 | g/cm3 |
Heat treatment
| Process | Temperature | Medium | Holding Time | Notes |
|---|---|---|---|---|
| normalizing | 850–880 °C | air | min 2 min per mm | — |
| quenching | 820–860 °C | water | min 30 min | Oil for larger sections |
| tempering | 540–660 °C | air | min 60 min | — |
Related materials
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).
S690QL
1.8928High-strength quenched and tempered fine-grain structural steel with minimum yield strength of 690 MPa. Used for heavily loaded structures like mobile cranes, mining equipment, bridges, and pressure vessels.
S275JR
1.0044Medium-strength structural steel with minimum yield strength of 275 MPa. Bridges the gap between S235JR and S355JR. Used for general structural applications, lattice towers, masts, and light crane components. Impact tested at +20°C (JR).
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