Wind Power Project: Tower Flanges & Main Shafts

Client & Background

A Northern European wind turbine OEM needed tower connection flanges and main shaft forgings for a 48-unit, 4.5MW-class onshore wind farm expansion. European forge shops could not meet the schedule, so the client searched in Asia.

The Challenge

Level 1 UT acceptance, -40°C Charpy impact testing for shafts, strict flange concentricity and wall-thickness uniformity, first 24 sets in 16 weeks, monthly lots thereafter.

Our Solution

DHDZ produced tower flanges by seamless rolled-ring forging and main shafts by open-die forging in modified 42CrMo steel. All normalizing and QT heat treatment was done in-house; 100% UT to ASTM A388 level 1; machining allowance held to 5mm; every flange marked with heat number, drawing revision and bolt-hole orientation.

Project Execution

First 24 sets delivered 3 weeks ahead of contract; remaining lots on schedule. Across all 48 sets (96 flanges + 48 shafts), zero rejections; third-party pre-shipment inspection passed at first presentation on every lot.

The Result

The client signed a 2-year framework agreement and added forged tubes for hydraulic pitch systems to their regular purchasing scope.

Why DHDZ

Forging, heat treatment, testing and documentation all under one roof, managed as a dedicated project. For wind power programs, that end-to-end control is what protects the erection season.