半工艺无取向电工钢的相关检测与研究

【作者】 李敏；

【导师】 肖于德；

【作者基本信息】 中南大学 ， 材料学， 2008， 硕士

【摘要】 根据涟源钢铁公司电工钢生产工艺的需要,本文分四个部分研究了无取向电工钢变形行为及退火处理对组织与性能的影响。第一部分采用了Gleeble-1500热力模拟机对无取向电工钢进行等温恒应变热压缩实验,研究了无取向电工钢合金热变形流变应力行为及组织演变规律,并建立了流变应力的数学模型。第二部分检验试验设备（爱泼斯坦方圈）的精准性,尤其是,在采用非标准爱泼斯坦方圈时,评估其结果的精确性,为后续磁性能的检测奠定理论基础。第三部分考察了不同退火参数条件下,材料组织与磁性能变化规律,确定了合理的、节能的退火工艺。第四部分主要研究本实验材料无取向电工钢夹杂物的类型及其对该材料组织和磁性能的影响。通过实验研究,得到以下结论:1)采用包含温度和激活能Q的双曲正弦形式的Arrhenius关系模型,进行计算铸态试样与热轧态试样的高温流变参数,计算结果能很好的与试验数据相吻合。故双曲正弦形式的Arrhenius关系模型能用于计算无取向电工钢的热塑性变形流变应力。半工艺硅钢铸轧试样与热轧板试样二者的本构关系方程需要分段构建。铸轧板坯500℃-800℃时应力水平因子α=0.039MPa^-1,应力指数n=7.93,结构因子A=42.1s^-1,热变形激活能Q=334.8kJ/mol;950℃-1200℃时应力水平因子α=0.1258MPa^-1,应力指数n=5.29,结构因子A=42.1s^-1,热变形激活能Q=769.9kJ/mol。热轧板坯500℃-800℃温度段的α=0.037MPa^-1,n=9.37,A=41.1s^-1,Q=329kJ/mol:900℃-1100℃温度段,α=0.106MPa^-1,n=5.97,A=43.5s^-1,Q=505.8kJ/mol。2)依照（GB/T 3655-92）国标取样,在TYU-2000M型硅钢片自动测量装置上,采用爱波斯坦方圈可以测定半工艺电工钢的磁性能,结果精确。3)半工艺电工钢板材加热过程中除了发生α-Fe回复、再结晶与晶粒长大外,还伴随有α-Fe←→γ-Fe相变,以及可溶相AlN和MnS的溶解和析出。可通过控制晶粒度与均匀性、有利织构取向以及降低位错密度来获得优良的磁性能。快速升温、较高温退火和短时间保温的生产工艺有利于获得节能的、磁性能优良的无取向电工薄板。4)在α-Fe←→γ-Fe相变温度以下,随着退火温度升高,{111}＜112＞的体积含量降低,{001}＜100＞织构和高斯织构含量增大;高于α-Fe←→γ-Fe相变温度,{111}＜112＞和{111}＜110＞织构含量、高斯织构以及{001}＜100＞织构含量均略有减小,但温度过高,{111}＜112＞和{111}＜112＞含量会明显增大,高斯含量降低。升温速度增加,{1111｝＜112＞和{111}＜112＞含量减少,高斯织构含量增多。5)本试验中半工艺电工钢总体上是纯净的,夹杂物主要是颗粒状Al₂O₃以及含SiO₂、CaO、FeO、Fe₂O₃、MnS等的Al₂O₃复合夹杂物。存在的夹杂物造成成分和组织不均匀性。因此,在保证材料纯度的前题下,采用合理的热处理工艺制度,利用相变以控制晶粒尺寸、晶粒均匀性、织构取向及其密度、位错密度、控制有利的析出相从而获得磁性能优良的无取向硅钢薄板。更多还原

【Abstract】 According to the practical process of electrical steel of Hunan Valin Lianyuan Iron and Steel group,the influences of deformation behavior and annealing treatment on the microstructure and properties of non-oriented electrical steel are discussed in four parts.In the first part,the isothermal constant strain hot compression behavior was studied by Gleeble-1500 thermodynamic simulator.The microstructure evolution during the hot deformation process was studied and the flow stress model was established.In the second part,the accuracy of the equipment（Epstein frame）,especially nonstandard epstein frame,used to measure the magnetic properties of non-oriented electrical steel was investigated.In the third part,the evolution of the microstructure and the magnetic properties under different annealing process was studied.The optimum annealing process was established.In the final part, the type of inclusions and their influence on the magnetic properties of non-oriented electrical steels were investigated.By the above research,the following conclusions were obtained:1)The stress level factorα,stress exponent n,structure factor A and hot deformation actviation energy Q are calculated by hyperbolic sine Arrhenius model containing temperature and activation energy.The results are conformed with the experiment data.Therefore hyperbolic sine Arrhenius can be used in flow stress of hot plastic deformation of electrical steel.The constitutive equations of hot-rolling slab and casting-rolling slab of semi-process electrical steel need subsection construction.When the deformation temperature is in 500-800℃,to casting-rolling slab,stress level factor of is 0.039MPa^-1,stress exponent is 7.93,structure factor is 1.571s^-1,and hot deformation activation energy is 334.8kJ/mol.But when the deformation temperature is in 1050-1200℃, stress level factor of is 0.1258MPa^-1,stress exponent is 5.29,structure factor is 1.03s^-1,and hot deformation activation energy is 769.9kJ/mol.To hot-rolling slab,when the temperature is in 500-800℃,stress level factor of is 0.037MPa^-1, stress exponent is 9.37,structure factor is 41.1s^-1,and hot deformation activation energy is 329kJ/mol.But when the temperature is in 900-1100℃,stress level factor of is 0.106MPa^-1,stress exponent is 5.97,structure factor is 43.5s^-1,and hot deformation activation energy is 505.8kJ/mol. 2)The Samples of semi process electrical steel were prepared according to national standard（（GB/T 3655-92）.The magnetic properties of samples were measured by Epstein frame on TYU-2000M.The results shown that equipment of TYU-2000M can measure the magnetic properties of smei process electrical steel accurately.3）During the hot processing of semi-process electrical steel sheet,α-Fe recovery,recrystallization and grain growth took plcae.Meanwhile,α-Fe←→γ-Fe transformation as well as dissolution and precipitation of soluble phase AlN and MnS were also occurred during that process.Excellent magnetic properties can be obtained by controlling grain size and homogeneity,texture orientation and dislocation density.Therefore,high heating rate,high temperature annealing and short holding time are beneficial to get non-oriented electrical steel sheet with low-cost and excellent magnetic properties.4)When annealing temperature was lower than the temperature ofα-Fe←→γ-Fe transformation,with the temperature increased,the amount of {111}<112> texture declined,but {001}<100> texture amplified as well as Goss texture.When the annealing temperature is higher thanα-Fe←→γ-Fe transformation temperature,the amount of {111}<112> texture,{111}<110>texture,{001}<100>texture and Goss texture declined significantly,but {111}<112> and {111}<112> texture raised when the temperature wsa too high.{111}<112> and {111} <112> texture decreased and Goss texture increased slightly with the increasing of heat up rate.5)The samples in this test are pure to some degree,but some inclusions, which are mainly Al₂O₃ sphericial particles and some Al₂O₃ containing SiO₂、CaO、FeO、Fe₂O₃、MnS,make component and structure asymmetric.Therefore,non-oriented electrical steel with excellent magnetic properties can be obtained by controling the amout of inclusion,heat treatment process,the grain size,grain homogeneity,orient and density of texture,dislocation density, precipitation of phase.More work should be done to ehance the magnetic properties of non-oriented electrical steel.更多还原