轧制工艺对低牌号无取向电工钢相变退火组织、织构与磁性能的影响
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摘要
将低牌号无取向电工钢的原始铸坯采用不同的工艺轧制得到5组样品,在H_2气氛下进行相变退火处理,使其发生α→γ→α相变,采用EBSD、XRD和磁性能测量技术确定了不同轧制工艺对低牌号无取向电工钢相变退火组织、织构与磁性能的影响。结果表明,与常规再结晶退火处理相比,相变退火处理可显著粗化晶粒降低成品板铁损;相变过程中存在织构遗传现象,相比于热轧-冷轧工艺,直接冷轧工艺相变退火后更有利于获得{100}织构,并显著改善成品板的磁性能;低温热轧比高温热轧能保留更多的{100}取向晶粒,相变退火后成品板中的非{111}取向晶粒增多,并提高了成品板的磁性能;此外,工业板中P和Al元素的偏聚或氧化对相变退火后成品板的组织、织构与磁性能有不利影响。
Non-oriented electrical steel sheets are important metallic functional materials for the iron cores in transformers and electrical motors, which require the performance characteristics of low iron loss and high magnetic induction. The magnetic properties of electrical steel critically depend on the microstructure and the occurring texture components. In addition, alloy elements can affect the magnetic properties by altering the electrical resistivity, microstructure and texture. At present, the quality of commercial non-oriented electrical steels are mainly optimized by the control of deformation, recrystallization parameters and chemical composition. And the microstructure, texture and magnetic properties are significantly influenced by the rolling process before recrystallization annealing. The favorite {100} texture in such condition takes at maximum only about 20% in volume fraction. In contrast, phase transformation combined with deformation can lead to nearly 80% volume fraction of {100}-oriented grains. In this work, the influence of rolling process on the microstructure, texture and magnetic properties of low grades non-oriented electrical steel after phase transformation annealing was studied by means of EBSD, XRD and magnetism measuring techniques. The starting material is a columnar-grained industrial low grades electrical steel cast slab. Five different initial microstructures are obtained after different rolling processes, the α→γ→α phase transformation annealing of samples is conducted in a tube furnace under H+2 atmosphere.The results show that phase transformation annealing can significantly coarsen grains and reduce the iron loss of non-oriented electrical steels compared with traditional recrystallization annealing. And the phase transformation texture is influenced by texture memory. Compared with hot rolling-cold rolling process, more {100}-oriented grains are obtained and the magnetic properties of non-oriented electrical steels are improved significantly after phase transformation in the directly cold rolling process. The proportion of non-{111} oriented grains increases and more initial {100}-oriented grains are retained after phase transformation in the process with lower hot rolling temperature, which improve the magnetic properties of final sample. In addition, the presence of P and Al elements in commercial electrical steels may affect the microstructure, texture and magnetic properties of non-oriented electrical steels due to segregation and oxidation after phase transformation.
Non-oriented electrical steel sheets are important metallic functional materials for the iron cores in transformers and electrical motors, which require the performance characteristics of low iron loss and high magnetic induction. The magnetic properties of electrical steel critically depend on the microstructure and the occurring texture components. In addition, alloy elements can affect the magnetic properties by altering the electrical resistivity, microstructure and texture. At present, the quality of commercial non-oriented electrical steels are mainly optimized by the control of deformation, recrystallization parameters and chemical composition. And the microstructure, texture and magnetic properties are significantly influenced by the rolling process before recrystallization annealing. The favorite {100} texture in such condition takes at maximum only about 20% in volume fraction. In contrast, phase transformation combined with deformation can lead to nearly 80% volume fraction of {100}-oriented grains. In this work, the influence of rolling process on the microstructure, texture and magnetic properties of low grades non-oriented electrical steel after phase transformation annealing was studied by means of EBSD, XRD and magnetism measuring techniques. The starting material is a columnar-grained industrial low grades electrical steel cast slab. Five different initial microstructures are obtained after different rolling processes, the α→γ→α phase transformation annealing of samples is conducted in a tube furnace under H+2 atmosphere.The results show that phase transformation annealing can significantly coarsen grains and reduce the iron loss of non-oriented electrical steels compared with traditional recrystallization annealing. And the phase transformation texture is influenced by texture memory. Compared with hot rolling-cold rolling process, more {100}-oriented grains are obtained and the magnetic properties of non-oriented electrical steels are improved significantly after phase transformation in the directly cold rolling process. The proportion of non-{111} oriented grains increases and more initial {100}-oriented grains are retained after phase transformation in the process with lower hot rolling temperature, which improve the magnetic properties of final sample. In addition, the presence of P and Al elements in commercial electrical steels may affect the microstructure, texture and magnetic properties of non-oriented electrical steels due to segregation and oxidation after phase transformation.
引文
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[19]Wang L N,Yang P,Mao W M.Analysis of martensitic transformation during tension of high manganese TRIP steel at high strain rates[J].Acta Metall.Sin.,2016,52:1045(王丽娜,杨平,毛卫民.高锰TRIP钢高速拉伸时的马氏体转变行为分析[J].金属学报,2016,52:1045)
[20]Zhang L W,Yang P,Mao W M.Phenomena of S3 and orientation gradients in an electrical steel applieda→g→a transformation[J].Acta Metall.Sin.,2017,53:19(章楼文,杨平,毛卫民.电工钢相变组织中的S3和取向梯度现象[J].金属学报,2017,53:19)
[21]Tomida T,Wakita M,Yasuyama M,et al.Memory effects of transformation textures in steel and its prediction by the double Kurdjumov-Sachs relation[J].Acta Mater.,2013,61:2828
[22]Lischewski I,Gottstein G.Nucleation and variant selection during the a-g-a phase transformation in microalloyed steel[J].Acta Mater.,2011,59:1530
[23]Yoshinaga N,Inoue H,Kawasaki K,et al.Factors affecting texture memory appearing througha→g→a transformation in IF steels[J].Mater.Trans.,2007,48:2036
[24]Sung J K,Lee D N.Evolution of crystallographic texture in pure iron and commercial steels byg to a transformation[J].Mater.Sci.Forum,2012,706-709:2657
[25]Nakayama T,Honjou N.Effect of aluminum and nitrogen on the magnetic properties of non-oriented semi-processed electrical steel sheet[J].J.Magn.Magn.Mater.,2000,213:87
[26]Hou C K,Hu C T,Lee S.The effect of aluminium on the magnetic properties of lamination steels[J].IEEE Trans.Magn.,1991,27:4305
[27]Park J T,Woo J S,Chang S K.Effect of phosphorus on the magnetic properties of non-oriented electrical steel containing 0.8 wt%silicon[J].J.Magn.Magn.Mater.,1998,182:381
[28]Lee S,De Cooman B C.Effect of phosphorus on the magnetic losses of non-oriented 2%Si steel[J].ISIJ Int.,2012,52:1162
[2]Ghosh P,Chromik R R,Knight A M,et al.Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels[J].J.Magn.Magn.Mater.,2014,356:42
[3]Li H Z,Liu H T,Liu Z Y,et al.Characterization of microstructure,texture and magnetic properties in twin-roll casting high silicon non-oriented electrical steel[J].Mater.Charact.,2014,88:1
[4]Sung J K,Lee D N,Wang D H,et al.Efficient generation of cubeon-face crystallographic texture in iron and its alloys[J].ISIJ Int.,2011,51:284
[5]Sung J K,Koo Y M.Magnetic properties of Fe and Fe-Si alloys with{100}<0vw>texture[J].J.Appl.Phys.,2013,113:17A338-1
[6]Tomida T.A new process to develop(100)texture in silicon steel sheets[J].J.Mater.Eng.Perform.,1996,5:316
[7]Xie L,Yang P,Xia D S,et al.Microstructure and texture evolution in a non-oriented electrical steel duringg→a transformation under various atmosphere conditions[J].J.Magn.Magn.Mater.,2015,374:655
[8]Xie L,Yang P,Zhang N,et al.Formation of{100}textured columnar grain structure in a non-oriented electrical steel by phase transformation[J].J.Magn.Magn.Mater.,2014,356:1
[9]Zhang L W,Yang P,Wang J H,et al.Transformation of{100}texture induced by surface effect in ultra-low carbon electrical steel[J].J.Mater.Sci.,2016,51:8087
[10]Zhang L W.Research on the mechanism of{100}transformation texture induced by surface-effect in the electrical steels[D].Beijing:University of Science and Technology Beijing,2016(章楼文.电工钢中表面效应诱发{100}相变织构的机理研究[D].北京:北京科技大学,2016)
[11]Fang F,Lu X,Lan M F,et al.Effect of rolling temperature on the microstructure,texture,and magnetic properties of strip-cast grainoriented 3%Si steel[J].J.Mater.Sci.,2018,53:9217
[12]De Paepe A,Eloot K,Dilewijns J,et al.Effect of hot rolling parameters on the magnetic properties of a low-silicon ultra-lowcarbon steel[J].J.Magn.Magn.Mater.,1996,160:129
[13]Sidor J J,Verbeken K,Gomes E,et al.Through process texture evolution and magnetic properties of high Si non-oriented electrical steels[J].Mater.Charact.,2012,71:49
[14]Fischer O,Schneider J.Influence of deformation process on the improvement of non-oriented electrical steel[J].J.Magn.Magn.Mater.,2003,254-255:302
[15]Gutiérrez-Casta?eda E J,Salinas-Rodríguez A.Effect of annealing prior to cold rolling on magnetic and mechanical properties of low carbon non-oriented electrical steels[J].J.Magn.Magn.Mater.,2011,323:2524
[16]Yashiki H,Okamoto A.Effect of hot-band grain size on magnetic properties of non-oriented electrical steels[J].IEEE Trans.Magn.,1987,23:3086
[17]Chang S K,Huang W Y.Effect of normalizing of hot band on magnetic properties and texture in high silicon non-oriented electrical steels[J].Steel Res.Int.,2007,78:340
[18]Zhang N,Yang P,Mao W M.Influence of columnar grains on the cold rolling texture evolution in Fe-3%Si electrical steel[J].Acta Metall.Sin.,2012,48:782(张宁,杨平,毛卫民.柱状晶对Fe-3%Si电工钢冷轧织构演变规律的影响[J].金属学报,2012,48:782)
[19]Wang L N,Yang P,Mao W M.Analysis of martensitic transformation during tension of high manganese TRIP steel at high strain rates[J].Acta Metall.Sin.,2016,52:1045(王丽娜,杨平,毛卫民.高锰TRIP钢高速拉伸时的马氏体转变行为分析[J].金属学报,2016,52:1045)
[20]Zhang L W,Yang P,Mao W M.Phenomena of S3 and orientation gradients in an electrical steel applieda→g→a transformation[J].Acta Metall.Sin.,2017,53:19(章楼文,杨平,毛卫民.电工钢相变组织中的S3和取向梯度现象[J].金属学报,2017,53:19)
[21]Tomida T,Wakita M,Yasuyama M,et al.Memory effects of transformation textures in steel and its prediction by the double Kurdjumov-Sachs relation[J].Acta Mater.,2013,61:2828
[22]Lischewski I,Gottstein G.Nucleation and variant selection during the a-g-a phase transformation in microalloyed steel[J].Acta Mater.,2011,59:1530
[23]Yoshinaga N,Inoue H,Kawasaki K,et al.Factors affecting texture memory appearing througha→g→a transformation in IF steels[J].Mater.Trans.,2007,48:2036
[24]Sung J K,Lee D N.Evolution of crystallographic texture in pure iron and commercial steels byg to a transformation[J].Mater.Sci.Forum,2012,706-709:2657
[25]Nakayama T,Honjou N.Effect of aluminum and nitrogen on the magnetic properties of non-oriented semi-processed electrical steel sheet[J].J.Magn.Magn.Mater.,2000,213:87
[26]Hou C K,Hu C T,Lee S.The effect of aluminium on the magnetic properties of lamination steels[J].IEEE Trans.Magn.,1991,27:4305
[27]Park J T,Woo J S,Chang S K.Effect of phosphorus on the magnetic properties of non-oriented electrical steel containing 0.8 wt%silicon[J].J.Magn.Magn.Mater.,1998,182:381
[28]Lee S,De Cooman B C.Effect of phosphorus on the magnetic losses of non-oriented 2%Si steel[J].ISIJ Int.,2012,52:1162