Effect of surface roughness on magnetic properties of electrical steels

Project: Other projectMiscellaneous project

Project Details

Description

Summer project funded by the Centre for Energy Efficient Materials (CEEM) at York, paying for an undergraduate intern for 8 weeks.
Project Abstract:Electrical steels are iron-silicon alloys (typically 3.2% silicon) that are used in electrical generators, transformers and end use devices such as motors which are important for the global economy to function. These steels are complex in nature and involve several stages of thermo-chemical-mechanical treatment to produce and have low magnetic / electrical losses due to the development of precise metallographic texture. Two types of electrical steels exist and are known and grain oriented and non-oriented electrical steels.In grain oriented electrical steels, the crystallographic texture if such that the material has lowest magnetic losses in one direction (the rolling direction) which makes them ideal for use in electrical transformer cores where magnetic flux is processed in a single direction. These steels are typically 0.23-0.30mm thick, have large grain sizes and a (110)<001> texture.With non-oriented electrical steels, the crystallographic texture is such that the material has good magnetic losses in all directions which makes them ideal for electrical generators and motor where the flux continues to change direction as the generator or motor rotate. These steels are typically 0.10-0.65 mm thick, have 100 um diameter grain sizes and a (100)<001> texture. During the manufacture of these products, various thermos-chemical-mechanical treatments are performed on the material which results in surface irregularities such as surface undulations, oxide formation, stresses, embedded particles and other contamination. All these features have an impact on magnetic losses and efforts to avoid / control them are made in the manufacturing process such as the use of inert atmospheres etc. Studies have been undertaken to understand the phenomena of surface polishing on magnetic performance of electrical steels which show the polishing to be beneficial to the product.This project will investigate the local magnetic phenomena around the surface of electrical steels in order to determine the mechanism of magnetic interference with magnetic flux movement through the material, potentially model the effect and develop and test improved philosophies for beneficial surface refinement.
StatusFinished
Effective start/end date23/07/1821/09/18