Abstract
Thin laminations of non-grain oriented (NO) electrical steels form the magnetic core of rotating electrical machines. The magnetic properties of these laminations are therefore key elements for the efficiency of electric drives and need to be fully utilized. Ideally, high magnetization and low losses are realized over the entire polarization and frequency spectrum at reasonable production and processing costs. However, such an ideal material does not exist and thus, achievable magnetic properties need to be deduced from the respective application requirements. Parameters of the electrical steel such as lamination thickness, microstructure and texture affect the magnetic properties as well as their polarization and frequency dependence. These structural features represent possibilities to actively alter the magnetic properties, e.g., magnetization curve, magnetic loss or frequency dependence. This paper studies the influence of production and processing on the resulting magnetic properties of a 2.4 wt% Si electrical steel. Aim is to close the gap between production influence on the material properties and its resulting effect on the magnetization curves and losses at different frequencies with a strong focus on occurring interdependencies between production and mechanical processing. The material production is realized on an experimental processing route that comprises the steps of hot rolling, cold rolling, annealing and punching.
Highlights
The efficiency and performance of rotating electrical machines are largely determined by the magnetic characteristics of the fully-finished, non-oriented electrical steel sheets used for the magnetic core of the machines
Properties are inherited over the different processing steps[1,2] and a detailed consideration of the consecutive impact on the material has to be established with further consideration of interdependencies, in particular between the annealed sheet material and the mechanical processing.[3]
The hot-strip thickness and cold-rolling reduction has a noticeable influence on the magnetization and loss, even if the proceeding production steps are analogous
Summary
In this paper results of a large-scale laboratory experimental study on the production and processing of nine different material states due to different production routes and further interaction with mechanical cutting are presented. In immediate proximity to industrial standards cutting experiments are performed on an industrial mechanical single action press with a cutting clearance of 7 %, a fixed cutting speed and a sharp tool.[3] A detailed microstructure and texture analysis of the material states, according to previously established techniques in different layers over the steel cross section, is applied. Thereby, the homogeneity and anisotropy in the microstructure, which can vary significantly for different final states can be accounted for. Subject of this paper is the micro-macro-mapping of magnetic properties and microstructure, texture and mechanical stress due to the production process. A final evaluation of strong interdependencies and distinguishable tendencies is presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
