Precipitate characterization in electrical steels using combination of SANS and VSANS

Purpose and goal

Non-oriented electrical steel grades are used for the magnetically active parts of electrical motors, generators, and actuators. The magnetic properties of these materials, among other factors, are highly influenced by the concentration, size, and type of precipitates. Although in some cases the existence of very small precipitates can be beneficial for the strength of the material, they are often detrimental to the magnetic properties. The aim of this project was to use a nondestructive statistical method to characterize precipitates in bulk.

Expected results and effects

The results of this project will provide a deeper understanding of precipitate formation in electrical steel and its effect on the magnetic and mechanical properties of the materials. The outcome of this project helps Surahammar Bruks AB to adjust the production parameters and avoid the formation of precipitates, or overcome the effect of precipitates on the properties of the final product. Improving the properties of electrical steel confers great economic and environmental benefits by reducing energy waste and increasing the efficiency and lifetime of electric motors.

Planned approach and implementation

The small angle neutron scattering method was used, and the measurements were performed on SANS-1 instrument at the Swiss Spallation Neutron Source, Switzerland. Representatives from Swerim and Surahammars Bruks were present during the measurements. In one set of materials small particles (<15nm) were added deliberately to increase the strength of the material, while another group of materials contained precipitates and particles that were detrimental to the magnetic properties. each measurement was performed by stacking ten laminates, each 0.3 mm thick in transmission mode.>