Effect of vanadium content and annealing temperature on recrystallisation, grain growth, and magnetic propertiesin 0-3%Si electrical steels

Abstract

The effects of vanadium content, ranging from 0.002 to 0.011 wt-%, and annealing temperature on recrystallisation and grain growth characteristics, texture development, and magnetic properties in cold rolled 0.3% Si electrical steel have been studied.The results indicate that fine VN and VC, precipitated during hot band coiling, diffuses the deformation texture and retards the growth of recrystallised grains. The finish temperature of recrystallisation is raised from 953 K for 0.002% V steel to 1033 Kfor steel containing 0.011%V. As a result, core loss increases sharply with increasing vanadium content for steels annealed at 1033 K. However, core loss is almost independent of vanadium content for steels annealed at 1133 K, owing to dissolution of VN and VC which liberates the constraint on grain growth and results in pronounced intensification of {111} <121> orientation in the subsurface region. The unfavourable magnetic properties of steels containing vanadium annealed at 1033 K are improved partlyby a second box anneal at temperatures above 1073 K. Core loss values are decreased via abnormal grain growth, whereas flux density values are also decreased significantly since grains undergoing abnormal growth are almost all {111} //N D (normal direction) oriented.