Analysis of Material Application and Manufacturing Process of Wind Turbine Tower Flanges

Wind power flanges mainly use low-alloy high-strength steel (such as Q345E/S355NL) to adapt to -40℃ low temperature and 12-level wind environment13. The materials are divided into three categories:

1. Carbon steel: It has good mechanical properties and machinability and is used for conventional onshore units.

2. Alloy steel: Containing elements such as chromium, nickel, and molybdenum, it improves strength and wear resistance and is suitable for large-megawatt offshore wind turbines (such as 18MW models).

3. Stainless steel: Excellent corrosion resistance, used in high salt spray offshore wind farms.

Core applications in the wind power field:

• Tower section connection: Bearing the towers own weight, wind load and vibration, the diameter can reach 5 meters (such as 16MW models).

• Offshore wind power: It needs to resist seawater corrosion and typhoon loads, and the flange thickness can reach 100mm.

• Extended fields: Heavy industries such as nuclear power and oil and gas equipment.

The manufacturing process strictly follows forging standards:

1. Forging and ring rolling: Formed by forging presses of 3600 tons or more, and φ6300mm CNC ring rolling machines process ring blanks.

2. Heat treatment: Normalizing is the key—accurate temperature control to refine grains, avoid Widmanstätten structure defects, and improve mechanical properties.

3. Precision machining: Five-meter CNC vertical lathes process flange flatness and bolt holes to ensure dimensional accuracy (error ≤ 0.05mm).

4. Inspection: 100% ultrasonic testing (Level II standard) and magnetic particle testing