Inline monopile longitudinal welds inspection
Industrial context
Monopiles are the most widely used foundation type in offshore wind farms. They are formed by a single large-diameter steel tube driven into the seabed, onto which the wind turbine tower is mounted. Their cost-effectiveness and straightforward installation make them the preferred solution for many offshore projects.
Large steel plates are rolled into cylindrical or conical sections using specialized bending machines. They are then welded longitudinally. These rolled and welded sections are referred to as “cans.” The cans are then aligned side by side and circumferentially welded .
The inspection of monopile welds is complicated by their sheer scale and restricted accessibility. With diameters reaching several meters and wall thicknesses exceeding 100 mm, ultrasonic waves must penetrate vast volumes of steel, making the reliable detection of small flaws more difficult. The cylindrical and conical geometry further complicates probe positioning, scanner tracking, and maintaining consistent coupling across long weld seams.
Monopile fabrication projects demand extremely high productivity, as thousands of meters of thick welds must be inspected within tight project timelines.
Our inline system is purpose-built to meet the unique challenges of monopile fabrication, delivering fast, accurate, and fully automated longitudinal weld inspection. At its core, the solution integrates multiple Phased Array Ultrasonic Testing (PAUT) boards driving several PAUT probes, ensuring complete weld coverage with the flexibility to adapt to varying diameters and wall thicknesses.
The system combines the high productivity of PAUT for rapid detection with the precision of Total Focusing Method (TFM) for accurate defect sizing, giving fabricators both speed and confidence in weld integrity. A dedicated inspection software package complements the hardware, providing real-time stripcharts for each delay law and automated defect sizing the moment an indication is detected.
By uniting advanced electronics, robust PAUT/TFM imaging, and intelligent software into one inline platform, our solution streamlines inspection, enhances weld quality assurance, and helps monopile manufacturers meet tight project deadlines with full confidence in compliance and safety.
