Tooth bending failure from inclusions - Gear defects

Tooth bending failure from inclusions - Gear defects - Other defects

Figure 1: Tooth bending failure from inclusions. An inclusion in the steel caused this intermediate pinion tooth to fail.

Defect name: Inclusion
Record No.: 2023
Type of defect (Internal/Surface): Surface
Defect classification: Gear defects, other defects
Steel name: Steel
Steel composition in weight %: No data.
Note: Wind-turbine gearboxes. Tooth bending failure from inclusions. Inclusions are minute impurities in steel, such as alumina or sulfides, which are introduced in the steel-making process. Steel used to manufacture wind-turbine gears is generally high quality and clean. However, an inclusion in an area subject to high stress can initiate failure. These types of failures can happen early in the life of the gearbox, especially in the high-speed gearing section.
To avoid inclusion-induced failures, gearbox manufacturers must have purchase specifications that require high-cleanliness steel. Some wind-turbine gearbox manufacturers demand steel cleanliness levels above those required in current gearbox standards.
Reference: Not shown in this demonstration version.