1. Specifications & Capability
FUSHUN METAL ring-rolls slewing ring blanks in 42CrMo4 (1.7225), up to 5000 mm outside diameter, for yaw and pitch bearing rings. The blanks are quenched and tempered, then supplied ready for raceway machining and hardening.
Ring rolling produces a continuous circumferential grain flow, which gives the raceway the fatigue resistance a slewing bearing demands. The raceway surface can be hardened to the bearing maker’s requirement after machining.
| Grade | Standard | Outside Diameter |
|---|---|---|
| 42CrMo4 / 1.7225 | EN 10250-3 | 2000-5000 mm |
| C50 / 1.0540 | EN 10083-2 | 2000-5000 mm |
2. Components & Service Conditions
Slewing rings are the large-diameter bearing rings that support the yaw and pitch motion of a wind turbine, and the slewing motion of cranes, excavators and tunnel boring machines. The ring carries heavy, off-centre loads while rotating slowly, so the raceway must resist rolling-contact fatigue without distortion.
The 42CrMo4 quenched and tempered ring provides the strength and toughness for the body, while the raceway is subsequently surface hardened. Ring rolling aligns the grain flow circumferentially, the direction of the rolling-contact load, which is why a ring-rolled blank outperforms a flame-cut plate in fatigue life.
3. Grade Equivalents – 42CrMo4 / C50
| Designation | Standard | Notes |
|---|---|---|
| 42CrMo4 / 1.7225 | EN 10250-3 | Standard slewing ring steel |
| C50 / 1.0540 | EN 10083-2 | Plain carbon option |
| AISI 4140 | SAE J404 | US equivalent of 42CrMo4 |
| SCM440 | JIS G4105 | Japanese equivalent |
| 40Cr | GB/T 3077 | Reference only, not used in certification |
| Grade | C | Si | Mn | Cr | Mo |
|---|---|---|---|---|---|
| 42CrMo4 (1.7225) | 0.38-0.45 | 0.40 max | 0.60-0.90 | 0.90-1.20 | 0.15-0.30 |
| C50 (1.0540) | 0.47-0.55 | 0.40 max | 0.60-0.90 | – | – |
The chromium and molybdenum of 42CrMo4 provide the deep hardenability needed for raceway hardening on large ring sections.
4. Manufacturing Process
Melting. FUSHUN METAL melts in an electric arc furnace with ladle refining and vacuum degassing for cleanliness.
Ring rolling. The billet is upset, pierced and ring-rolled to the required outside diameter, producing continuous circumferential grain flow around the raceway.
Heat treatment. The ring is quenched and tempered; the raceway is then surface hardened after machining to the bearing maker’s requirement.
Testing. UT, hardness and dimensional verification, with full traceability.
5. Standards & Certification
Slewing ring blanks are supplied to EN 10250-3, with inspection certificates under EN 10204 3.1. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forgings: wind turbine main shafts and wind turbine flanges.
6. Typical Applications
Wind yaw bearings
Yaw bearing rings for wind turbine nacelles.
Wind pitch bearings
Pitch bearing rings for blade adjustment.
Cranes
Slewing rings for tower and mobile cranes.
Tunnel boring machines
Slewing rings for shield machines and excavators.
7. Inquiry Essentials
To quote your slewing ring, please provide the outside diameter, inside diameter and height, the required hardness, and the expected batch quantity.
