Girth gears are used to drive large, rotating systems such as dryers, rotary kilns or horizontal mills. The flexible concept from SEW-EURODRIVE has simplified manufacturing, transport and assembly. Traditional girth gears generally consist of two to four segments and are assembled together for processing. This requires extremely large and expensive machines for production, handling and heat treatment. Besides this, the size of component parts creates disadvantages with regard to casting quality and heat treatment. The innovative girth gears from SEW-EURODRIVE are always divided into several identical segments. This means the component parts are short and easy to handle. By combining the latest materials engineering and state-of-the-art manufacturing methods, the SEW-EURODRIVE girth gears avoid the disadvantages of the traditional manufacturing process and create new benefits. SEW‑EURODRIVE only uses austempered ductile iron (ADI) for the production of the girth gears. The classical materials cannot match its tensile strength. ADI is described in detail in the following international standards: International Organization for Standardization 17804 "Ausferritic spheroidal graphite cast irons" & AGMA 939-A07 "Austempered Ductile Irons For Gears".