New welding technology for repairing cast iron components in wind turbines

Challenge

The large cast iron components in wind turbines are expensive and often impossible to repair if defects occur during casting or machining. As a result, many cast parts are discarded. However, if the components could instead be repaired through welding, both time and costs would be reduced, and the carbon footprint significantly lowered. Some cast parts for wind turbines are becoming so large that they are difficult to cast, and only a few foundries can handle the task. If a large component can be cast in multiple pieces and later joined through welding, costs are saved, and the supplier base is significantly expanded.

Solution

The solution was to develop a welding technology for cast iron and methods to ensure the quality of welds—both for repairs and for joining components. Quality control was conducted using a new ultrasonic technology that could identify flaws in the welds. This would make assembly welding and repair welding safer in practice.

Result

The project partners have developed a new welding method that enables the repair of large cast iron components in wind turbines. The technology simplifies the repair process and can lead to more resource-efficient maintenance of turbines, thus reducing both time, costs, and CO2 emissions in the wind energy sector.

Through the project, a quality specification, a test guideline, and a repair catalog have been developed—download the industry standard here.

To enable widespread implementation in the industry, further work is needed to develop and demonstrate welding procedures with s/n curve indications. If successfully implemented, analyses show that the project will result in savings of ½-1% of the total cost of a wind turbine, which is currently around €3M. The costs for the nacelle will be reduced by approximately 10-15%