Steel Grade Datasheet
39NiCrMo3/ 1.6510 / ≈ 9840Nickel-Chromium-Molybdenum Q&T Steel
What is 39NiCrMo3 steel?
39NiCrMo3 (Werkstoff No. 1.6510, ≈AISI 9840) is a nickel-chromium-molybdenum quenched and tempered steel, a common shaft and gear material especially in Italy. The nickel addition gives higher toughness and hardenability than 42CrMo4. In the quenched and tempered (+QT) condition it provides a 590–785 MPa yield and 780–1180 MPa tensile strength depending on section — ideal for medium-to-heavy dynamically loaded parts.
Chemical Composition
Cast analysis, % by weight (per the applicable EN standard)
| Element | Range (%) |
|---|---|
| C | 0.35–0.43 |
| Si | ≤ 0.40 |
| Mn | 0.50–0.80 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 0.60–1.00 |
| Mo | 0.15–0.25 |
| Ni | 0.70–1.00 |
Mechanical Properties (+QT)
Values depend on ruling section / thickness (d).
| Section (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) |
|---|---|---|---|
| d ≤ 16 | 785 | 980–1180 | 11 |
| 16 < d ≤ 40 | 685 | 880–1080 | 12 |
| 40 < d ≤ 100 | 590 | 780–930 | 13 |
Hardness: +A (annealed): ≤ 250 HB · +QT: typically 250–320 HB (~26–34 HRC)
39NiCrMo3 / 1.6510 properties and use
International Equivalents
Values marked ≈ are nearest matches, not exact equivalents. Always confirm against the governing standard.
| System | Grade |
|---|---|
| EN | 39NiCrMo3 |
| W.-Nr. (DIN) | 1.6510 |
| AISI/SAE | ≈ 9840 |
| ASTM | A29 (9840) |
| JIS | ≈ SNCM439 |
| GOST | ≈ 40ХН (40KhN) |
| BS (UK) | ≈ 640M40 (EN111) |
| GB (China) | ≈ 40CrNiMoA |
Applications
- Shafts, axles and spindles
- Gears and pinions
- Connecting rods
- High-strength bolts and studs
- Machine parts under dynamic load
- Forged automotive and machine parts
Available Product Forms
Frequently Asked Questions
What is the difference between 39NiCrMo3 and 42CrMo4?+
39NiCrMo3 contains nickel (0.7–1.0%), 42CrMo4 does not. Nickel raises toughness and hardenability, so 39NiCrMo3 is slightly superior for parts under impact/fatigue load. 42CrMo4 is more common and economical. Their strength classes are similar.
Is 39NiCrMo3 the same as AISI 9840?+
The nearest American equivalent is AISI 9840; the composition is very close (nickel-chromium-molybdenum, ~0.4% C). It corresponds to 640M40 (EN111) in the British system and ≈40KhN in the Russian one. For critical work follow the ordering standard.
What hardness does 39NiCrMo3 reach?+
In the quenched and tempered (+QT) condition it is typically 250–320 HB (~26–34 HRC). Tensile strength ranges 780–1180 MPa depending on section, with higher values in thin sections.
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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).