| Non-oriented silicon steel is widely used in various motor products,and its magnetic properties are important to motor efficiency.The magnetic properties of non-oriented silicon steel are determined by two aspects: core loss(iron loss)and magnetic induction(magnetic induction).High magnetic induction and low iron loss are the guarantee of good magnetic performance,which is significant for energy saving.At the same time,due to the environmental problems of service,the corrosion resistance of non-oriented silicon steel is also one of the aspects that worthy to be attention.The main factors for the magnetic properties are grain size,texture composition and inclusion.The previous works showed that rare earth plays a significant role in these three aspects and is beneficial for improving magnetic properties.However,the present work does not explore the mechanism of the influence of rare earth on recrystallization texture,and there is little research on the effect of rare earth on corrosion resistance.In this paper,the different chemical composition of 2.9% of Si-0.8% Al non-oriented silicon steel with five cerium content,0,0.0005%,0.0036%,0.0058%,and 0.0101%(mass percent)were prepared by vacuum induction melting,hot rolling,cold rolling,atmosphere annealing,etc.The effects of cerium content on the microstructure,texture and corrosion resistance were studied by OM,SEM,TEM,and electrochemical methods.(1)The average grain size of the annealed samples of non-oriented silicon steel first increases with increasing cerium content(the grain size of sample with 0.0058% Ce is the largest)and then decreases.And the dislocation density of the cold-rolled sheet having a higher cerium content is smaller.Ce can be metamorphosed and combined with Al,O,S,etc.in steel to form large-sized ellipsoidal compounds,which can reduce the amount of fine inclusions such as AlN and MnS in steel.So,the effect of fine inclusions on the impeding grain boundary migration and grain growth is reduced.In addition to the modification of AlN and MnS inclusions,the excess cerium element will also be combined with S and O to increase the nucleation rate of the high melting point oxysulfide,resulting in an increase in inclusions,inhibiting the grain boundary movement and enhancing the average grain size of the annealed sheet.Thus,the grain size of annealed samples is reduced..(2)The samples with the highest content of cerium have better corrosion resistance than other samples containing cerium,and the samples with the highest content of cerium have the best corrosion resistance.This is the result of a combination of inclusions and grain size.Appropriate amount of cerium(0.0058%)reduces the number of fine inclusions,reduces the suppression of grain growth by fine inclusions,reduces the grain size of the sample,and increases the grain boundary area,which is beneficial to the improvement of corrosion resistance,but increases the amount of coarse inclusions.The corrosion resistance of the quantity decreases,while the excess cerium(0.0101%)play an opposite effect,which reduces the grain size but is larger than that of the cerium-free sample,and the corrosion resistance of the sample is improved.(3)The recrystallized grain growth rate of the sample containing 0.0058% of cerium is faster,and the proper amount of cerium can significantly enhance the {110} surface texture and improve the {100} and {110} surface texture components and reduce the {111} surface texture component.This is because an appropriate amount of cerium can reduce the number of fine inclusions and hinder the effect of grain growth;and since the {111}-oriented grains preferentially nucleate near AlN and MnS,the number of inclusions such as AlN and MnS is reduced.So,the nucleation of {111} oriented grains can be effectively suppressed. |
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