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30CrNiMo8
Qilu
Product Description
Hot forged 30CrNiMo8 round bar supplied QT, 50 mm to 800 mm, with heat treatment, ultrasonic testing and rough machining done in-house.
Equivalent to: DIN 30CrNiMo8 / 1.6580 · Werkstoff 1.6580 · close to ASTM 4340 mod (higher Ni)
DIN 1.6580 Alloy Steel in Stock
Supply form — Round bar, forgings, blocks
Process — Hot forged
Condition — QT (quenched & tempered), 248–341 HB
Diameter range — 50–800 mm
Standard — DIN EN 10083-3 / DIN 17200
Certificate — EN 10204 3.1 standard, 3.2 on request
Lead time — 25–40 days for large forgings
30CrNiMo8 (1.6580) is the top-end Ni-Cr-Mo alloy structural steel in DIN EN 10083-3. With 1.8–2.2 % chromium and 1.8–2.2 % nickel it hardens through very large sections and holds toughness at high strength — which is why it is specified for big rotor forgings, pressure vessel shells and heavily loaded marine shafts where 34CrNiMo6 runs out of capacity.
| Element | C | Si | Mn | P (max) | S (max) | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|
| DIN EN 10083-3 | 0.26–0.33 | ≤ 0.40 | 0.50–0.80 | 0.025 | 0.025 | 1.80–2.20 | 1.80–2.20 | 0.30–0.50 |
Typical values for the QT condition. Large-section forgings are mapped for hardness across the section.
| Property | QT (typical) |
|---|---|
| Tensile strength, Rm (MPa) | 1000–1200 |
| Yield strength, Re (MPa) | ≥ 800 |
| Elongation, A5 (%) | ≥ 10 |
| Impact, KV (J) | ≥ 35 (at 20 °C) |
| Hardness (HB) | 269–341 |
| Standard | Designation |
|---|---|
| DIN / EN (Germany/Europe) | 30CrNiMo8 / 1.6580 |
| ASTM (USA) | ~4340 mod (higher Ni) |
| JIS (Japan) | SNCM439 (close family) |
| Werkstoff Nr. | 1.6580 |
| GB (China) | ~35CrNi3Mo (close) |
Power generation — large rotor shafts, turbine discs, generator forgings
Pressure vessels — high-strength shells, flanges, nozzles
Marine — propeller shafts for large vessels
Offshore — mooring shafts, hinge pins
30CrNiMo8 is oil-quenched from 850–880 °C and tempered at 580–660 °C. Because the section sizes are large, the tempering cycle is set by the actual forging OD to reach the required combination of yield and Charpy. We always map hardness across the section — for rotors in particular, a soft core or a brittle core is unacceptable.
Most suppliers in this business are traders who subcontract everything. We run our own processes, which means shorter cycles and one point of accountability when something needs fixing.
Heat treatment shop — quenching and tempering to your target hardness, with furnace charts recorded per batch
Machining shop — rough turning, peeling and cutting to length, so your bar arrives ready for finish machining
Testing — ultrasonic per ASTM A388 / EN 10228-3, hardness mapping across the section, tensile and impact testing
Certification — EN 10204 3.1 as standard, 3.2 available with third-party witness (ABS, BV, CCS, GL)
Export packing — bundled, end-capped and rust-protected for sea freight
A1: For forgings above ~500 mm or where impact toughness at high strength is critical. 30CrNiMo8 has higher Ni and Cr, so it holds properties through larger sections. For general heavy shafting 34CrNiMo6 is more economical. See our 34CrNiMo6 page.
A2: Yes. We forge 30CrNiMo8 to 800 mm, ultrasonically test to ASTM A388 / EN 10228-3 and rough-turn the OD. Furnace charts, UT map and EN 10204 3.1 come with the shipment; 3.2 with third-party witness on request.
A3: 30CrNiMo8 has more nickel (1.8–2.2 % vs 1.65–2.0 %) and is more tightly controlled for large-section rotor service; 4340 is the American general-purpose high-strength grade. We supply both — tell us which spec your drawing calls up.
Send us your diameter, length, quantity, required hardness and destination port. You will get a quotation with the full technical proposal within 24 hours.
