Heat treatment demands for the production of wind energy plants

For building a wind energy plant a variety of thermal and thermochemical treated parts are required. The big dimensions of most of the parts in combination with high requirements on reliability and consistency of the heat treatment results show the need for optimized heat treatment solutions. The variety of parts which are to be heat treated will be shown in combination with the required process and the furnace design. Fasteners, for example, usually have to be tempered in seal quench furnace plants. For the large bearings different furnace types can be used; the advantages and disadvantages of the different concepts will be discussed. Big gears are usually hardened by induction with a single tooth hardening. A very important, time and money consuming process is the case hardening of gear wheels and shafts, which are usually carburized in vertical pit-type furnaces. Alternative concepts like big seal quench furnaces or ring hearth furnaces will be presented and discussed. It will be shown that the ring hearth furnace will allow to drop heat treatment costs in comparison with pit-type furnaces.