What is 34CrNiMo6 steel?
34CrNiMo6 is a medium-carbon alloy steel with about 0.34 % carbon, 1.5 % chromium, 1.5 % nickel and 0.2 % molybdenum. The name follows the EN 10027 system: 34 is the carbon content in hundredths of a percent, and the "6" is the chromium content multiplied by four. In the European numbering system it is 1.6582.
Nickel raises toughness, chromium and molybdenum raise hardenability, and molybdenum also suppresses temper embrittlement. Together they let 34CrNiMo6 reach high strength after quenching and tempering in sections that plain chromium-molybdenum steels such as 42CrMo4 cannot harden through. It is widely used for heavily loaded shafts, gears, rings and crankshafts subject to torsion, impact and fatigue.
For open-die forgings the governing standard is EN 10250-3 (open steel die forgings for general engineering purposes, alloy special steels). EN 10083-3 covers the same grade as quenched and tempered bar and is the usual reference for smaller sections.
34CrNiMo6 chemical composition
| Element | C | Si | Mn | P | S | Cr | Mo | Ni |
|---|---|---|---|---|---|---|---|---|
| Cast analysis | 0.30–0.38 | ≤ 0.40 | 0.50–0.80 | ≤ 0.035 | ≤ 0.035 | 1.30–1.70 | 0.15–0.30 | 1.30–1.70 |
| Permissible product deviation | ± 0.02 | + 0.03 | ± 0.04 | + 0.005 | + 0.005 | ± 0.05 | ± 0.03 | ± 0.05 |
EN 10083-3 sets a tighter phosphorus limit of P ≤ 0.025 %. State the governing standard, and any restricted sulphur or hydrogen limits, on your enquiry.
34CrNiMo6 mechanical properties
Strength in 34CrNiMo6 falls as the section gets thicker, because the core cools more slowly during quenching. Minimum values are therefore given per ruling section (tR), the thickness that controls the cooling rate of the forging.
| Property | Direction | tR ≤ 160 mm | 160 < tR ≤ 330 mm | 330 < tR ≤ 660 mm |
|---|---|---|---|---|
| Yield strength Re min, MPa | – | 600 | 540 | 490 |
| Tensile strength Rm min, MPa | – | 800 | 750 | 700 |
| Elongation A min, % | Longitudinal | 13 | 14 | 15 |
| Transverse | 9 | 10 | 11 | |
| Impact energy KV min, J | Longitudinal | 45 | 45 | 40 |
| Transverse | 22 | 22 | 20 |
| Diameter d, mm | Re min, MPa | Rm, MPa | A min, % | Z min, % | KV min, J |
|---|---|---|---|---|---|
| ≤ 16 | 1000 | 1200–1400 | 9 | 40 | 35 |
| 16 – 40 | 900 | 1100–1300 | 10 | 45 | 45 |
| 40 – 100 | 800 | 1000–1200 | 11 | 50 | 45 |
| 100 – 160 | 700 | 900–1100 | 12 | 55 | 45 |
| 160 – 250 | 600 | 800–950 | 13 | 55 | 45 |
Annealed (+A) hardness: max. 248 HB. Values are minimums unless a range is given; the edition of the standard named on the purchase order governs. Higher strength levels can be agreed for a specific ruling section.
34CrNiMo6 equivalent grades
| Standard / country | Grade | How close |
|---|---|---|
| EN (Europe) | 34CrNiMo6, 1.6582 | Same grade |
| AISI / SAE (USA) | 4340 | Closest; higher C (0.38–0.43 %), lower Cr (0.70–0.90 %) |
| BS 970 (UK) | 817M40 (EN24) | Near equivalent |
| AFNOR (France) | 35NCD6 | Near equivalent |
| JIS (Japan) | SNCM439 | Comparable; check C and Cr |
| GB/T 3077 (China) | 40CrNiMoA | Comparable; lower Cr |
Equivalents are not interchangeable without checking chemistry and property requirements against the drawing. If your specification calls for a different grade, send it to us and our engineers will confirm what we can supply.
Forging and heat treatment of 34CrNiMo6
| Operation | Temperature | Cooling |
|---|---|---|
| Hot forging | 1100 → 850 °C | Slow cool in furnace or sand |
| Soft annealing (+A) | 650–700 °C | Furnace; max. 248 HB |
| Normalising (+N) | 850–880 °C | Air |
| Hardening | 830–860 °C | Oil or polymer |
| Tempering (+QT) | 540–660 °C | Air |
Long shafts are quenched vertically in two 15 m well-type furnaces to limit distortion; rings, discs and blocks are treated in car-bottom furnaces up to 8,000 × 2,000 × 2,000 mm. Each charge is recorded, and the heat-treatment chart is supplied with the certificate.
34CrNiMo6 forged products we supply
- Seamless rolled rings
- Rectangular or contoured section, OD up to 6,000 mm, for bearings, gear rings and slewing rings.
- Forged rings
- Upset and punched rings for heavy walls or sizes outside the ring-mill range, from OD 50 mm.
- Forged shafts
- Stepped, gear, pinion, eccentric and crankshafts; turned lengths up to 14 m.
- Forged flanges
- Standard and custom flanges, couplings and hubs.
- Discs and blocks
- Solid discs, gear blanks and blocks, machined up to Ø5,000 mm.
- Round and flat bars
- Forged bars supplied as-forged, rough-turned or peeled.
- Hollow bars and sleeves
- Bored cylinders, sleeves and bushings up to Ø1,600 × 10,000 mm.
- Valve and wellhead parts
- Stems, seat rings, blocks and bodies for ball, gate, globe and check valves.
Parts are supplied as-forged with machining allowance, proof-machined for ultrasonic testing, or finish-machined to drawing.
Applications of 34CrNiMo6 forgings
| Industry | Typical 34CrNiMo6 parts |
|---|---|
| Power generation and wind | Generator and turbine shafts, rotor discs, gearbox shafts, bearing and slewing rings |
| Oil and gas | Wellhead and Christmas-tree components, subsea parts, drilling equipment, forged nozzles |
| Pumps and compressors | Plunger-pump and chemical-pump shafts, compressor shafts, sleeves and discs |
| Valves | Valve stems, seat rings, blocks and bodies for ball, gate, globe, check and plug valves |
| Heavy machinery and mining | Gears, pinion shafts, crankshafts, eccentric shafts, rolls, press parts, crane wheels |
| Shipbuilding and marine | Intermediate and propeller shafts, couplings, rudder components |
| Automotive and motor construction | Highly stressed crankshafts, axles and drive components |
How we produce and test 34CrNiMo6 forgings
All steps are carried out at our plant in Jiangyin, and each forging is traceable to its melt number.
- Melt and refine. Electric arc furnace, ladle furnace and vacuum degassing to control hydrogen and inclusions; heats up to 60 t. Electroslag remelting is available on request.
- Forge or ring-roll. 6,300 t, 4,000 t and 2,000 t hydraulic presses and radial-axial ring mills up to 6 m; minimum forging ratio agreed to the specification.
- Heat treat. Annealing, normalising or quenching and tempering in 14 recorded furnaces.
- Machine. Vertical lathes to Ø5,000 mm, horizontal lathes to 14 m and CNC deep-hole drilling.
- Test. Spectrometer chemistry, tensile, Charpy V-notch impact (to −60 °C), hardness, ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388, and magnetic particle inspection.
- Certify and ship. EN 10204 3.1 as standard; 3.2 witnessed by BV, DNV, LR, SGS, TÜV or your inspector. The works holds CCS, BV, DNV, LR and NK approvals.
Request a quote for 34CrNiMo6 forgings
Quotations are usually returned within two working days. The minimum order is 10 kg with no minimum piece count, and normal lead time is 20 to 60 days. Please include the following in your enquiry:
- Grade and standard, for example 34CrNiMo6 +QT to EN 10250-3
- Drawing (PDF, DWG, DXF or STEP) or finished dimensions
- Quantity and expected repeat volume
- Delivery condition: as-forged, proof-machined or finish-machined
- Required properties, ultrasonic standard and acceptance class
- Certificate type (3.1 or 3.2) and destination port
34CrNiMo6 forging FAQ
What is 34CrNiMo6 steel?
34CrNiMo6 (European material number 1.6582) is a nickel-chromium-molybdenum alloy steel for quenching and tempering, specified in EN 10083-3 and, for open-die forgings, in EN 10250-3. It contains about 0.34 % carbon and 1.5 % each of nickel and chromium plus 0.15–0.30 % molybdenum, giving good hardenability and high strength with good toughness in large sections.
What is the equivalent of 34CrNiMo6?
The closest American grade is AISI/SAE 4340; the British equivalent is 817M40 (the former EN24), and the French designation is 35NCD6. JIS SNCM439 and GB 40CrNiMoA are comparable. These grades are near-equivalents, not identical: AISI 4340, for example, carries more carbon (0.38–0.43 %) and less chromium (0.70–0.90 %). Always specify the governing standard on the order.
What is the tensile strength of 34CrNiMo6?
It depends on the section size and heat treatment. In the quenched and tempered condition to EN 10083-3, tensile strength is 1000–1200 MPa for diameters of 40–100 mm and 900–1100 MPa for 100–160 mm. For large open-die forgings to EN 10250-3, the minimum is 800 MPa up to a 160 mm ruling section, 750 MPa up to 330 mm and 700 MPa up to 660 mm.
Which 34CrNiMo6 forged products does Jiangyin Jiangnan Metal supply?
Seamless rolled rings, forged rings, shafts (stepped, gear, pinion, eccentric and crankshafts), flanges, discs and blocks, round and flat bars, hollow bars, sleeves and bushings, gear blanks and valve parts. Rolled rings go up to 6,000 mm outside diameter and single forgings up to 30 tonnes, subject to the property requirements of the ruling section.
How is 34CrNiMo6 heat treated?
Typical practice is hardening from 830–860 °C with an oil or polymer quench, followed by tempering at 540–660 °C to the required strength. Forgings can also be supplied soft annealed (650–700 °C, max. 248 HB) or normalised (850–880 °C). Jiangyin Jiangnan Metal quenches long shafts vertically in 15 m well-type furnaces to limit distortion.
Is 34CrNiMo6 weldable?
Weldability is poor because of the high hardenability, so welding is normally avoided. If welding is necessary, it requires a preheat of around 300 °C or more, controlled interpass temperature and a post-weld stress relief or re-temper, qualified by a welding procedure test.
What testing and certificates come with 34CrNiMo6 forgings?
Each forging is ultrasonically tested to EN 10228-3, SEP 1921 or ASTM A388 as ordered, with chemical analysis, tensile, Charpy impact and hardness testing in the on-site laboratory. An EN 10204 3.1 mill certificate is standard; EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TÜV or the customer's inspector is available on request.
What is the minimum order and lead time for 34CrNiMo6 forgings?
The minimum order is 10 kg with no minimum piece count. Normal lead time is 20 to 60 days from order confirmation, and quotations are usually returned within two working days of receiving a drawing or specification.
Where is the 34CrNiMo6 forging factory located?
Jiangyin Jiangnan Metal Co., Ltd. is at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, on the south bank of the Yangtze between Shanghai and Nanjing. Contact: +86 189 2135 9659, sales@steelforgepieces.com.
Contact us
Jiangyin Jiangnan Metal Co., Ltd. is an integrated steel melting and open-die forging works that has supplied forgings to North America, Europe, the Middle East and Asia-Pacific since 1997.
No.1 Chengxiqiao Road, Zhouzhuang Town,Jiangyin City, Jiangsu Province, China
Telephone / WhatsApp / WeChat: +86 189 2135 9659
Email: sales@steelforgepieces.com
Hours: Monday–Saturday, 08:00–17:30 China Standard Time (UTC+8)