1. Specifications & Capability
FUSHUN METAL ring-rolls wind turbine flanges – tower, nacelle and blade flanges – in S355J2+N (1.0577) and 42CrMo4 (1.7225), up to 5000 mm outside diameter. Every flange is 100% ultrasonically tested to EN 10228-3.
Ring rolling produces continuous circumferential grain flow and eliminates the weld seam of a fabricated flange, giving the structural integrity and fatigue life a tower connection demands.
| Grade | Standard | Outside Diameter |
|---|---|---|
| S355J2+N / 1.0577 | EN 10025 | 3000-5000 mm |
| 42CrMo4 / 1.7225 | EN 10250-3 | 3000-5000 mm |
2. Components & Service Conditions
Wind turbine flanges join the tower sections, the tower to the nacelle, and the blades to the hub, carrying both static and fluctuating wind loads over a 20-year design life. The bolted connection is a fatigue-critical detail, so the flange must be sound, flat and free of internal defects.
S355J2+N provides the structural strength with guaranteed low-temperature toughness, while 42CrMo4 is used where a quenched and tempered flange of higher strength is required. Ring rolling removes the weld seam of a fabricated flange and aligns the grain flow circumferentially, and the 100% ultrasonic test confirms freedom from the internal defects that would shorten fatigue life.
3. Grade Equivalents – S355J2+N / 42CrMo4
| Designation | Standard | Notes |
|---|---|---|
| S355J2+N / 1.0577 | EN 10025 | Structural steel, normalized |
| 42CrMo4 / 1.7225 | EN 10250-3 | QT alloy steel option |
| A572 Gr.50 | ASTM A572 | US structural equivalent |
| Q345E | GB/T 1591 | Reference only, not used in certification |
| Grade | C | Si | Mn | Cr | Mo |
|---|---|---|---|---|---|
| S355J2+N (1.0577) | 0.20 max | 0.55 max | 1.60 max | – | – |
| 42CrMo4 (1.7225) | 0.38-0.45 | 0.40 max | 0.60-0.90 | 0.90-1.20 | 0.15-0.30 |
The J2 quality guarantees Charpy impact toughness at -20 C, essential for cold-climate and offshore wind towers.
4. Manufacturing Process
Melting. FUSHUN METAL melts in an electric arc furnace with ladle refining for cleanliness and low-temperature toughness.
Ring rolling. The billet is upset, pierced and ring-rolled to the flange outside diameter, producing continuous circumferential grain flow and removing the weld seam.
Heat treatment. S355J2+N is normalized; 42CrMo4 is quenched and tempered.
Testing. 100% UT to EN 10228-3, plus dimensional and mechanical verification, with full traceability.
5. Standards & Certification
Wind turbine flanges are supplied to EN 10025 (S355J2+N) and EN 10250-3 (42CrMo4), with ultrasonic testing to EN 10228-3 and inspection certificates under EN 10204 3.1. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forgings: nuclear flange rings, large forged flanges and slewing rings.
6. Typical Applications
Tower flanges
Flanges joining wind turbine tower sections.
Nacelle flanges
Flanges connecting the tower to the nacelle.
Blade flanges
Root flanges for wind turbine blades.
Onshore & offshore
Flanges for onshore and offshore wind farms.
7. Inquiry Essentials
To quote your wind turbine flange, please provide the flange specification table, the required batch quantity, and the ultrasonic testing acceptance level.
