Shafts & RollersTransmission shafts
Wind Turbine Main Shaft
Forged steel main shaft for 850 kW–5 MW wind turbines, made from 34CrNiMo6 or 42CrMo4, machined to IT6 with Ra 0.8 and 100% UT/MT inspection.
Forging and material control
Main shafts are open-die forged from vacuum-degassed steel ingots with a forging ratio above 3:1, which reduces internal porosity and keeps the section sound. We work to EN, DIN, ASTM and GB material standards, with 34CrNiMo6 and 42CrMo4 as the common grades for wind turbine spindles.
After rough machining, each shaft is quenched and tempered to balance hardness and toughness, then stress relieved to limit dimensional movement during service. Heat treatment is recorded and can be reviewed with the inspection documents.
Machining and inspection
Heavy-duty CNC lathes and grinding centers machine the journals, flange faces and centering features. Dimensions are held to ISO IT6 and bearing or sealing fits to Ra 0.8 or better, so the shaft seats correctly against the rotor hub and gearbox.
Every shaft receives 100% ultrasonic testing to EN 10228-3 class 3/4 and magnetic particle testing. Results, material certificates and dimensional reports are supplied with the shaft for traceability from ingot to finished part.
Applications and customization
These shafts are used on onshore and offshore wind turbines from 850 kW to 5 MW, including gearbox retrofits and turbine overhauls. Maximum length is 6,000 mm; drawings and interface dimensions are matched to the nacelle layout.
We manufacture to customer drawings and technical specifications under ISO 9001:2015, with options for DNV/GL material certification. Anti-rust oil coating and vacuum packing are applied for sea freight.
Specifications
- Material
- 34CrNiMo6 / 42CrMo4
- Capacity
- 850 kW – 5 MW
- Max length
- up to 6,000 mm
- Heat treatment
- Quenching & tempering (QT), stress relieving
- Dimensional tolerance
- ISO IT6
- Surface finish
- Ra 0.8 or better
- NDT
- 100% UT (EN 10228-3 class 3/4) + MT
Common questions
- Can you machine this part to my drawing?
- Yes. Every part is quoted from the drawing. Send a PDF, DWG, DXF, STEP or IGES file with the material, quantity and any inspection requirements, and we reply within one working day.
- How are the material and heat treatment decided?
- They follow your drawing. The specification table shows the range normally used for this part type; the final material and heat treatment are confirmed with the quotation.
- What lead time and inspection come with the part?
- Lead time is set in the quotation and depends on material, size, quantity and inspection scope. Material verification, in-process checks and final inspection records are archived with the part, and any extra certification is agreed before production.
- How is the part packed for export?
- Export parts are rust-proofed and packed for the transport method and destination confirmed in the quotation, with lifting points and markings agreed before dispatch.
Every part is quoted from the drawing itself, not from a size band. Send it over and we answer with the process, the lead time and the tolerance we can hold.
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