Steel Grade Datasheet
34CrNiMo6/ 1.6582 / ≈ 4340
Nickel-Chromium-Molybdenum Q&T Steel
What is 34CrNiMo6 steel?
34CrNiMo6 (Werkstoff No. 1.6582, ≈AISI 4340 / UK EN24) is a nickel-chromium-molybdenum high-strength quenched and tempered steel per EN 10083-3. The nickel addition delivers uniform through-hardening even in large sections (high hardenability) plus superior toughness. In the quenched and tempered (+QT) condition it provides a 600–1000 MPa yield and 800–1400 MPa tensile strength depending on section — the material for large shafts, gears and forgings under heavy load.
Chemical Composition
Cast analysis, % by weight (per the applicable EN standard)
| Element | Range (%) |
|---|---|
| C | 0.30–0.38 |
| Si | ≤ 0.40 |
| Mn | 0.50–0.80 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 1.30–1.70 |
| Mo | 0.15–0.30 |
| Ni | 1.30–1.70 |
Mechanical Properties (+QT)
Values depend on ruling section / thickness (d).
| Section (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) |
|---|---|---|---|
| d ≤ 16 | 1000 | 1200–1400 | 9 |
| 16 < d ≤ 40 | 900 | 1100–1300 | 10 |
| 40 < d ≤ 100 | 800 | 1000–1200 | 11 |
| 100 < d ≤ 160 | 700 | 900–1100 | 12 |
| 160 < d ≤ 250 | 600 | 800–950 | 13 |
Hardness: +A (annealed): ≤ 248 HB · +QT: typically 270–330 HB (~28–36 HRC)
34CrNiMo6 / 1.6582 properties and use
International Equivalents
Values marked ≈ are nearest matches, not exact equivalents. Always confirm against the governing standard.
| System | Grade |
|---|---|
| EN | 34CrNiMo6 |
| W.-Nr. (DIN) | 1.6582 |
| AISI/SAE | ≈ 4340 / 4337 |
| ASTM | A29 (4340) |
| JIS | SNCM447 |
| GOST | ≈ 38ХН3МА (38KhN3MA) |
| BS 970 (UK) | 817M40 (EN24) |
| GB (China) | ≈ 40CrNiMoA |
Applications
- Heavy-duty shafts and large-diameter shafting
- Turbine and generator shafts
- Aircraft landing gear and aerospace parts
- Large gears and pinions
- High-strength bolts and studs
- Heavy-industry forgings
Available Product Forms
Frequently Asked Questions
What is the difference between 34CrNiMo6 and 42CrMo4?+
The main difference is nickel: 34CrNiMo6 contains 1.3–1.7% nickel, 42CrMo4 has none. Nickel raises hardenability and toughness, so 34CrNiMo6 hardens to the core in large sections (e.g. >100 mm) and gives higher strength. 42CrMo4 is economical and sufficient for medium sections, while 34CrNiMo6 is chosen where heavy load and large diameter are required.
Is 34CrNiMo6 the same as AISI 4340?+
The nearest American equivalent is AISI 4340 (EN24 / 817M40 in the British system). The compositions are very close; 4340 typically has a slightly higher carbon range. In aerospace and defence both are treated as the same 'ultra-high-strength' class; for critical work, follow the ordering standard.
What hardness and strength does 34CrNiMo6 reach?+
In the quenched and tempered (+QT) condition, typical hardness is 270–330 HB (~28–36 HRC). Tensile strength ranges 800–1400 MPa and yield 600–1000 MPa depending on section. Thin sections can reach up to 1400 MPa tensile.
Is 34CrNiMo6 weldable?+
With difficulty. Its high carbon equivalent creates a high cracking risk, requiring 250–350 °C preheat, low-hydrogen consumables and post-weld stress relief. It is generally shaped by forging or machining rather than welded.
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References & Standards
Values on this page are reference data compiled from the applicable EN standard; certified material properties are defined by the mill test certificate (EN 10204 3.1).