Towards lighter bearings: mapping dislocation density evolution using synchrotron X-ray diffraction (liXbe)

Purpose and goal:

The decay of bearing steel microstructure, including the carbon redistribution and carbide re-precipitation, is strongly dependent on the dislocations. It is therefore critical to quantify and understand the evolution of dislocation density in the steel subsurface. Within the LIGHTer Småföretag project, SME Scatterin AB teamed up with steel producer Ovako AB for 2D mapping of dislocation density evolution in the bearing steel subsurface using a novel synchrotron X-ray diffraction tool.

Expected results and effects:

The experiments were performed using high-resolution setup with a microbeam. Dislocation density gradients in the steel subsurface have been revealed in micrometer resolution. The acquired microstructural information during the project will be implemented by Ovako in their ongoing R&D efforts for designing better steel microstructure for more compact and lighter bearings.

The successful utilization synchrotron X-ray technique will enable Scatterin to create a solid showcase for future business opportunities. Approach and implementation:

Synchrotron X-ray diffraction measurements using microbeam were performed on the P21.2 Swedish Materials Science Beamline at the Petra III, DESY, Hamburg. Whilst Ovako has contributed to the project by providing steel expertise, sample preparation, and complementary lab-scale investigations, Scatterin has been responsible for the synchrotron XRD measurements and data analysis using their proprietary dislocation density analysis code package as part of their software under development: Scatterin SaaS.