Load Carrying Capacity of Case-Carburized Gears with Different Cryogenic Treatments

Gearboxes of modern drivetrains, e.g., in wind turbines, can be exposed temporarily to low ambient temperatures during their manufacturing or during operation. During manufacturing or assembly, for example, very low temperatures sometimes occur during joining processes due to the cryogenic treatment of the components. In these cases, the temperature depends on the cooling medium used (typically dry ice or liquid nitrogen). Furthermore, depending on the application, gearboxes may be exposed to low ambient temperatures up to -60 °C when used in cold regions. The low temperatures can have an impact on the component properties and thus on the gear load carrying capacity. Therefore, the knowledge of these influences is very important regarding the design and dimensioning of gearboxes. In this publication, further investigations on the load carrying capacity of cryogenic treated gears are presented based on previous research work. The focus is on results on the tooth root and pitting load carrying capacity. The load carrying capacity is analyzed in the context of changes in the component properties as a result of different low temperature treatments, and the dominant influencing factors are identified.