Effect of Sulfur Element on Microstructure and Magnetic Properties of the Finished Non-oriented Silicon Steel Sheets

Based on the industrial manufactured 0.25%Si non-oriented silicon steel sheets,the effect of sulfur concentration on microstructure and magnetic properties of the finished steel sheets was discussed,in order to find out the mechanism of sulfur element acting in non-oriented silicon steel sheets.The results show that when the sulfur concentration increases from 0.001 9% to 0.010 2%,there is a significant change of the morphology,size and number of the sulfides.The morphology of sulfide will change from capsular to ellipsoidal and then to spherical,and thus its type will change from the single MnS to the complex of MnS and Cu_xS,and then to single Cu_xS,respectively.The Cu_xS particles can pin the grain boundary and reduce the diffusion rate of grain growth effectively.Thus,fine grain segregation and island grain growth appear,which results in the heterogeneous distribution of fine grains.In a word,the magnetic induction of 0.010 2%S sample is superior to the 0.001 9%S sample,but the iron loss of which is inferior to the 0.001 9%S sample.Both of the difference value of eddy loss can keep steady,but the difference value of hysteresis loss will increase with the increasing of annealing temperature.This is the main factor causing the increase of total iron loss for 0.010 2%S sample.