Wind Turbine Forgings: A Buyer's Checklist for Material, Testing and Traceability
Release time：
2026-10-12
Wind Turbine Forgings: A Buyer's Checklist for Material, Testing and Traceability
Nanjing Liju Precision Forging Co., Ltd. ｜ Industry News ｜ October 2026
Cover: a large ring forging for a wind turbine, checked against the drawing (illustration — replace with factory photography)
Every wind turbine built in the last decade depends on a short list of critical forgings: main shafts, tower flanges, pitch and yaw bearing rings, gearbox components. These parts carry the highest loads in the machine — and the longest consequences if they fail. This article is a buyer's checklist: what the market looks like, which grades matter, and what evidence you should demand before placing an order.
01 · The Market: Wind Is Now a Forging Growth Engine
According to the Global Wind Energy Council's Global Wind Report 2026, around 165 GW of new wind capacity was installed worldwide in 2025, bringing cumulative capacity to roughly 1,299 GW. BloombergNEF puts 2025 new installations even higher, at 169 GW — up 38% year on year and the third consecutive record. Offshore wind is scaling fastest: China's offshore fleet alone reached 44.6 GW by September 2025, the world's largest for four consecutive years (National Energy Administration).
Every one of these turbines needs forged rings, flanges and shafts. More capacity means more forgings — and stricter quality expectations from the OEMs who buy them.
02 · The Forgings Inside a Turbine
Three families of forgings carry most of the load:
Main shafts and hollow spindles — transfer rotor torque into the drivetrain. Supplied quenched and tempered, often with 100% ultrasonic testing and low-temperature impact verification for cold-climate sites (Fushun Special Steel).
Tower flanges — connect tower sections. Made from fine-grain structural steels (e.g. Q355NE/Q355ND under Chinese GB specifications, or equivalent EN grades) with specified low-temperature impact toughness.
Bearing rings (pitch, yaw, main) — 42CrMo4-type alloy steel, through-hardened so the ring survives both surface wear and through-body fracture (Vinir Forge).
Fig. 1: Ultrasonic testing of a forged wind turbine shaft (illustration — replace with factory photography)
03 · The Grades That Dominate
42CrMo4 (EN 1.7225 / AISI 4140) is the benchmark Cr-Mo alloy for wind forgings: main shafts, gearbox input shafts and large flanges, typically delivered at 900–1,100 MPa tensile strength with good through-hardening across large sections (Fushun Special Steel). 34CrNiMo6 appears where higher core strength is needed. Tower flange steels in the Q355N series carry specified low-temperature Charpy requirements down to −40 °C or lower.
04 · Quality Evidence a Buyer Should Demand
Price is a small part of the risk. Before a forging goes into your turbine, verify:
Material certificates per EN 10204 (3.1 or 3.2) with heat numbers and mill test certificates, so every part traces back to its melt.
Heat treatment transparency: quench-and-temper parameters and resulting hardness bands (e.g. 220–260 HB for 42CrMo4) and mechanical properties from certified test pieces (Accio).
100% ultrasonic testing where the drawing calls for it, with the report and acceptance level stated.
Grain size and microstructure: typical requirement of grain size ≤ 6 per ASTM E112.
Low-temperature impact toughness matching your site climate, e.g. −40 °C Charpy.
05 · Common Pitfalls When Sourcing
Lowest price with no certificate package. The certificate is part of the part: without it, you cannot prove the grade, the heat treatment or the testing.
Mixed or substituted grades. Confirm the actual standard (ASTM / EN / GB) and the equivalent-grade table in writing.
Partial ultrasonic coverage. "Tested" means tested to a defined extent and acceptance level, documented in the report.
No traceability. If you cannot trace the heat number to the mill test certificate, you cannot trace the part in the field.
06 · A Supplier Checklist: What Liju Brings
Nanjing Liju Precision Forging has supplied forged parts to OEM markets since 2003 — automotive, high-speed rail, railway accessories, aviation (including parts for Airbus programs), mining, hydraulic, forklift (Toyota and Crown projects) and wind power forgings among them. Founded in 1998 and covering 34,000 m² in Nanjing's Liuhe Economic Development Zone, the plant runs 300T–1,600T friction screw presses and automated closed-die hot forging lines, plus a cold forging shop, machining, CAD/CAM tooling and an in-house laboratory — hardness, CMM, tensile, metallographic, spectroscopy and roughness testing — under ISO 9001, IATF 16949 and ISO 14001. Parts are exported to the United States, Germany, Italy, Canada and Japan.
Send your drawings to sales@njliju.com for a DFM review and quotation. Or call +86 138 5144 1727. The plant: No. 6 Longhua Road, Liuhe Economic Development Zone, Nanjing, China.
A forging is only as good as the evidence that comes with it.
Sources ｜ 资料来源（核验日期 2026-10-12）：
Global Wind Energy Council ｜ Global Wind Report 2026（2025 年新增约 165 GW、累计约 1,299 GW）
BloombergNEF ｜ 2025 Global Wind Turbine Manufacturer Market Share（2025 年新增 169 GW，同比 +38%，连续第三年创纪录）
国家能源局（National Energy Administration of China）｜ 2025 年 11 月海上风电数据（累计 44.6 GW，连续四年全球第一）
Fushun Special Steel ｜ Wind Turbine Main Shaft Forgings（主轴 QT 状态、100% UT、低温冲击；42CrMo4 抗拉 900–1,100 MPa）
GB 风能发电系统环形锻件技术规范 ｜ 中国锻压协会 T/CCMI 34—2024（塔架法兰 Q355NE/Q355ND、轴承环 42CrMo4A）
Vinir Forge ｜ Wind Energy Forging Supplier（主轴承环 42CrMo4 调质 + 感应淬火）
Accio ｜ Wind Turbine Forged Parts（硬度 220–260 HB、晶粒度 ≤6 ASTM E112、炉号追溯）
EN 10204 ｜ 金属产品检验文件类型（3.1 / 3.2 材料证书）
