The Role of the Technological Residual Stress in Spiral Bevel Gears’ Degradation

The subjects of the examination were automotive components, spiral bevel gears, built up by two main parts, the axle, where the component is prone to fracture, and the head segment, where the working surface can be found. The occasional fracture occurs during the straightening process after the hardening heat treatment. Our aims were to monitor the evolution of the residual stress during the manufacturing processes and to reveal the role of the residual stress in the component’s fracture. The residual stress measurements were carried out via non-destructive X-ray diffraction. To reveal the component’s fracture hardness tests and microstructure measurements were also performed. Based on the results, the fracture of the components were connected to the stress asymmetry which was derived from the microstructure of the early stages of manufacturing.