Study On Precipitation And Recrystallization In The Hot-rolling Process Of Rare Earth And Niobium Microalloyed Oriented Silicon Steel

Oriented silicon steel is an important soft magnetic alloy which plays an important role innational economic construction. It is known as the arts and crafts in steel products because of thecomplicated technology, strict microstructure and composition control. The key to obtainingsharp Goss texture is getting small inhibitors and a certain number of Goss grain, which derivefrom the hot-rolling process. Therefore, to get excellent magnetic oriented silicon steel, it is crucialto control the microstructure and precipitation during the hot-rolling process. Studies have shownthat, rare earth and niobium is beneficial to precipitating fine and dispersive second phase particlesin the process of hot-rolling, which is of great significance to obtain excellent magnetic orientedsilicon steel. But now the research on the hot-rolling process of rare earth and niobiummicroalloyed oriented silicon steel has not yet been reported.The influence of Rareearth and Niobium on the precipitation and recrystallization in the hot-rolling processwas not studied deeply. So in this paper, the rare earth and niobium microalloyed orientedsilicon steel precipitation and recrystallization during hot-rolling were researched.This paper takes general oriented silicon steel（CGO）with3.14wt%Si as the object of theresearch. In the laboratory, rare earth and niobium microalloyed oriented silicon steel wereprepared by vacuum induction furnace and then forged into forging stock which size is70×100×350mm.Gleeble-1500D was used to analyze the dynamic and static recrystallization.Metallographic microscope and Zeiss Suppra55SEM was used to observe the microstructure andsecond phase.The results showed that，rare earth and niobium microalloyed oriented silicon steel enteredintoγ+Fetwophaseregionat749℃.Whenthestrainratecame5s-1, at850℃and900℃,the strain capacity reached1.31and1.41respectively, the dynamic recrystallization happened.When the temperature reached1150℃and1070℃,in the different time interval, rare earth andniobium microalloyed oriented silicon steel occurred static recrystallization to some extent.During multi-pass compression, When the temperature was950℃and the accumulatedvariables reached2.23, the dynamic recrystallization happened. A large number of fine and dispersive AlN、MnS particles precipitated in the process of hot-rolling.The number of theprecipitation increased more in the subsequent coiling process. When the coiling temperaturereached690℃, the size of the precipitated phase particles is from30nm to60nm, and theseparticles are of strong pinning ability.