Nb含量对取向硅钢第二相粒子和性能的影响

Effect of Nb content on the second phase particle and properties of grain oriented silicon steel

制备了3种不同Nb含量的取向硅钢(w(Nb)依次为0、0.009%、0.025%),借助SEM、TEM、EDS等手段,系统分析了钢中第二相粒子的形貌、尺寸及分布等,并研究了Nb含量对取向硅钢组织、织构、力学性能及磁性能的影响。结果表明,Nb添加能够有效净化取向硅钢钢液,随着Nb含量从0增加到0.025%,钢中夹杂物数密度从577.5个/mm^(2)减少至156.6个/mm^(2),产生裂纹的可能性降低,有利于热轧和冷轧生产工序的顺利进行;此外,铸坯的室温力学性能也随着Nb含量的增加显著提升,这有利于高强度取向硅钢的生产。当取向硅钢中Nb添加量为0.009%时,渗氮板中析出物、组织和织构分布特点最有利于Goss晶粒在高温退火过程中异常长大,得到大尺寸二次再结晶晶粒,成品板磁性能优异,磁感应强度B800达到1.872 T,铁损P1.7/50仅为1.252 W/kg。

Three kinds of grain oriented silicon steels with different Nb contents(w(B)equals to 0,0.009%,0.025%,respectively)were prepared.By means of SEM,TEM,EDS and etc.,the morphology,size and distribution of second phase particles in steels were systematically analyzed,and the effects of Nb content on the structure,texture,mechanical properties and magnetic properties of the oriented silicon steel were studied.The results show that Nb addition can purify the liquid steel effectively.With the increase of Nb content from 0 to 0.025%,the number density of inclusions decreases from 577.5 number/mm^(2) to 156.6 number/mm^(2),the possibility of cracks is therefore reduced,which is conductive to the smooth progress of hot rolling and cold rolling production process.In addition,the room temperature mechanical properties of the ingots are also significantly improved with the increase of Nb content,which is beneficial to the production of high-strength grain oriented silicon steel.After nitriding treatment,the distribution characteristics of the precipitates,structure and texture of the steel plate with Nb content of 0.009%is most conductive to the abnormal growth of the Goss grains during the high temperature annealing process,and the large-size secondary recrystallized grains are obtained.The finished plate has excellent magnetic properties with the magnetic induction intensity B800 reaching 1.872 T but the iron loss P1.7/50 at only 1.252 W/kg.