Effect of Cross-Rolling on Microstructure, Texture and Magnetic Properties of Cold Rolled Non-Oriented Electrical Steels

Abstract

Cross rolled non-oriented (CRNO) electrical steel have uniform magnetic properties in all angular direction. However, controlling the texture for uniform magnetic properties of these steels has been investigated by many researchers. In the present thesis effect of cross-rolling and subsequent annealing of CRNO steels on their texture and magnetic properties have been investigated. Hot rolled non-oriented electrical steel samples were subjected to multi-step cross rolling of 80% reduction in thickness. The rolled samples were then annealed at 650, 750 and 850 oC for 1, 2 and 4hrs respectively. Two different types of samples were used for the present study: one had higher amount of aluminum (sample 1) and another had higher carbon, silicon, manganese, Sulphur and phosphorus content (sample 2). Sample1 had higher grain size as compare to that of sample2 after annealing. Average grain size was increased with increasing the temperature and soaking time of annealing. It was also observed that the various textures (111) <uvw> fiber, (001)<uvw> fiber, (110)<uvw> fiber <100> Goss orientation and <001> cubic orientation which were uniform along different directions of the samples. The magnetic property (in terms of core losses) was found to be lower for samples having higher grain sizes.