Forged gear blanks and gear rim blanks
Forged blanks for gears and gear rims up to 3,000 mm — with grain flow that carries right into the tooth root.
The service life of a gear is decided at the tooth root. In a forged blank the grain flow runs along the contour exactly there, whereas in a gear flame-cut from plate it is interrupted. For highly loaded gearboxes the forged blank is therefore not the more expensive option — it is the only one that carries the load.
We supply gear blanks, gear rim blanks and pinion shafts from 200 to 3,000 mm outside diameter and 20 kg to 15 tonnes. Depending on size and quantity closed-die forged, ring rolled or open-die forged. Standard grades are case-hardening steels such as 18CrNiMo7-6 and 17CrNiMo6, and for through-hardened gearing 42CrMo4 and 34CrNiMo6.
Technical data
| Outside diameter | 200 – 3,000 mm |
|---|---|
| Piece weight | 20 kg – 15 t |
| Processes | Closed-die forging, ring rolling, open-die forging |
| Materials | Case-hardening and quenched and tempered steels |
| Delivery condition | Annealed, quenched and tempered or normalised |
| Machining | As-forged, pre-turned, pre-cut teeth on request |
| Testing | UT to EN 10228-3, grain size, hardness profile, Jominy |
These are typical manufacturing ranges within our supplier network. Larger dimensions and special materials on request — send us your drawing.
Materials
- 18CrNiMo7-6 (1.6587)
- 17CrNiMo6 (1.6587)
- 20MnCr5 (1.7147)
- 42CrMo4 (1.7225)
- 34CrNiMo6 (1.6582)
- 31CrMoV9 (1.8519)
Manufacturing and quality assurance
- Process selected by diameter and quantity: closed-die forged for series, ring rolled for large gear rims, open-die forged for one-offs.
- Annealing for good machinability — the blank then goes into your gear cutting operation.
- Verification of grain size and, on request, hardenability via the Jominy end-quench test.
- Ultrasonic testing to EN 10228-3, with particular attention to the later tooth root area.
- Machining to the finished blank contour with hub bore and faces; pre-cut teeth on request.
Typical applications
- Large gearboxes in machinery and plant engineering
- Gear rims for rotary kilns and mills
- Wind turbine gearbox components
- Pinions and pinion shafts for drives
- Slewing rings for excavators and cranes
- Marine and industrial gearboxes
Frequently asked questions
Why forged gear blanks instead of flame-cut plate?
A gear cut from plate has an interrupted grain flow; at the tooth root, where the highest stresses occur, the grain runs across the load. A forged blank guides the grain along the contour and achieves substantially higher tooth root strength.
Do you supply blanks with pre-cut teeth?
On request, yes. The standard case is a turned blank that you finish in your own gear cutting shop. Pre-cutting and case hardening can be coordinated through our partner network where required.
Which materials do you recommend?
For case-hardened gearing 18CrNiMo7-6 or 17CrNiMo6, for through-hardened gearing 42CrMo4 or 34CrNiMo6, for nitrided gears 31CrMoV9. The choice follows module, load and your hardening process.
Is grain size documented?
Yes. For case-hardened gears the grain size drives distortion during hardening. We state it in the certificate and supply the Jominy end-quench result on request.
From what quantity is closed-die forging worthwhile?
Usually from a few hundred pieces, when the die cost per part becomes small and the near-net shape saves machining. Below that, ring rolled or open-die forged blanks are more economical — we cost both routes in the quotation.
What is the lead time for gear blanks?
Pre-machined, typically 8 weeks from release. For closed-die blanks, a first order also carries the die manufacturing time. Grades from our stock programme shorten the lead time.
Request a quote for Gear blanks
Send us your drawing or specification. You get feedback on feasibility, material selection and an indicative price — from engineers, not from a call centre.
Send enquiry