钢厂
无取向硅钢热轧边裂的形成原因
利用加热炉模拟、动态再结晶以及热模拟等试验方法以及扫描电镜、金相显微镜等分析观察手段对无取向硅钢边裂的成因进行了探讨。结果表明,长时间加热使得板坯边部晶粒异常长大,晶界氧化并脱碳,轧制过程中边部温度过低,动态再结晶过程变弱,使得板坯边部延伸性能变差,是导致硅钢边裂的主要原因。建议通过适当降低铸坯加热温度、缩短保温时间、提高终轧温度来改善硅钢边裂缺陷。 The behaviors of high temperature oxidation,dynamic recrystallization,and hot ductility,microstructure evolution were investigated on the non-oriented electrical steel sheets to discuss the formation of edge crack.The key causes of cracking was found to be the coarse as-cast microstructure,grain boundary oxidation and decarburization in reheating furnace,as well as reduced temperature at strip edge region during hot rolling process resulting in reduced hot ductility and lack of enough dynamic re...
冷轧无取向硅钢横向厚差控制
冷轧中中低牌号的无取向硅钢多采用万能凸度轧机(Universal crown mill,UCM)生产,其板形好坏受制于UCM轧机板形调节手段的协调使用。为掌握UCM轧机的板形控制特点,建立基于二维变厚度有限元的辊系弹性变形和基于三维差分的轧件塑性变形的六辊轧机耦合模型,对UCM轧机的板形调控性能进行详尽的分析,包括工作辊和中间辊弯辊、中间辊窜辊的调控功效、辊间接触压力分布等。在此基础上,提出可用指导生产的板形控制策略,指出UCM轧机在横向厚差控制方面的不足。针对工业生产中UCM轧机轧制无取向硅钢横向厚差大的问题,在大量仿真计算的基础上,开发具有高次曲线函数的边部变凸度(Edge variable crown,EVC)的工作辊。采用该工作辊后,各种品种的无取向硅钢的横向厚差不大于10μm的百分比由24%提高到99%,横向厚差的均值小于6μm,远小于之前的13μm。 Medium-low grade non-oriented silicon steel is rolled often by universal crown mill(UCM) during cold rolling.Its shape quality is dependent on the coordinated control of several shape adjustment devices of UCM.In order to understand the shape control characteristics of UCM,coupling model of six-high rolling mill,based on two-dimensional varying thickness finite element rolls elastic deformation model and three-dimensional finite difference strip plastic deformation model,is setup for the detaile...
冷轧无取向硅钢的边缘降控制优化研究
某冷连轧机生产无取向硅钢板材时,其边缘降的长度合格率频繁超标。为满足用户的叠片厚度精度要求,这类产品必须以增大切边量的方式来保证交货质量,而这种方式又直接降低了金属收得率,提高了生产成本。基于此,以该产线现有设备特性为基础,详细分析其软、硬件功能模式,分别对辊形与反馈控制进行全面分析与优化改进。通过现场试验论证,充分明确依托辊形优化与反馈控制程序的改进能显著提高边缘降的控制水平,该技术的使用为生产现场的边缘降控制提供了合理的技术支撑。 A cold rolling mill production of non-oriented silicon steel sheet,the thickness difference of the edge( edge-drop) is usually exceed the preset standard value,In order to meet the accuracy requirements of the user flatness,these production must be trimed wider length to meet the delivery quality of the user need, which directly reduce the metal yield and increase the manufacturing cost. Therefor,the software and hardware of the production line has been analyzed, and the work roll shape and feed...
无取向电工钢孔洞缺陷控制实践
针对马钢无取向电工钢孔洞缺陷的分布规律及形貌特征,对缺陷样进行了显微分析,并利用生产实绩数据分析了该缺陷产生的原因。结合热轧生产过程,主要通过避免带钢撞击导卫以及降低导卫结瘤的产生等措施,可有效抑制热卷异物压入产生,从而降低冷轧工序孔洞的产生。 In viewing of the distribution and morphology characteristics of the hole defect of non-oriented electrical steel in Maanshan Iron and Steel Co.,Ltd.,the causes of the defect were analyzed by micro analysis of the defect sample and the production data.Combined with the production process of hot rolling,by avoiding the impact of strip steel on the guide and reducing the nodule formation on the guide,the pressing of foreign bodies in hot coiling could be effectively suppressed,thus reducing the fo...
硅钢常化炉段工艺特征及问题分析
连续酸洗退火机组(CPAL)对于当前生产高磁感取向硅钢和高牌号无取向硅钢是必不可少的一个环节。常化炉是常化酸洗机组关键的组成部分。本文对国内自主建造的两条退火酸洗机组的工艺流程,特别是常化炉段进行了对比分析。总结出了常化炉的工艺及组成特点,对生产过程中暴露的问题进行了仔细的分析并提出了改进的意见,对于以后新建常化炉具有一定的提示作用。 The continous pickling annealing line(CPAL) is an essential step in producing high magnetic induction grain-oriented silicon steel and high grade non-oriented silicon steel.The normalizing furnace is a very important part of the CAPL.In this paper,the process flows of two CAPL with independent manufacture in our country have been compared,especially the part of normalizing furnaces.The characteristics of process and component are summarized and problems of the normalizing furnace during the prod...
电工钢反复弯曲试验的影响因素
电工钢反复弯曲次数是电工钢性能检验的重要指标之一,直接影响到用户在使用电工钢过程的机加工性能。主要分析了试样宽度、试样张力、晶粒取向、反复弯曲设备等因素对电工钢反复弯曲试验的影响,并对各个因素的影响程度进行量化以及原因探讨,从而归纳形成各影响因素的基本规律,以便为电工钢实际生产、用户使用提供科学指导。结果表明:试样宽度增加,反复弯曲次数也会不断增加,晶粒位向对取向电工钢的反复弯曲次数影响较大,当支座顶部到拨杆底部的距离减小或拉紧力增加时,反复弯曲次数会不断减小,但当拉紧力达到60N以上时,对反复弯曲次数影响不大,试样经退火后,反复弯曲次数略有上升。 The reverse bend number is an important performance of electrical steels′capabilities,affecting the machining performance directly when the customers used.It investigated some factors,such as sample′s width,sample′s tension load,grain orientation and equipment,how to effect the reverse bend test for electrical steel,measured the influence degree,and discussed the reason,in order to form basic rules which could be guided the manufacturing and using for electrical steel.Results showed that the rev...
基于GTN损伤模型对含边部缺陷硅钢薄板冷轧时边裂的预测
采用拉伸试验和显微组织观测的方法确定了GTN损伤模型中的9个损伤参数,运用GTN损伤模型对冷轧硅钢薄板边部缺陷的扩展及边裂的产生进行了有限元模拟,并与预置缺口的钢板轧制试验进行对比。结果表明:轧制过程中边部缺陷是造成钢板边部裂纹萌生和扩展的一个重要原因,GTN损伤模型可用来预测含边部缺陷硅钢薄板在冷轧过程中边裂的产生;预测结果与试验结果基本一致。 The crack initiation and propagation of silicon steel strip with edge defect during cold rolling process was studied by using GTN damage model in this paper.Nine damage parameters in GTN model were identified by tensile testing and microstructure observing,and then the FE simulation of edge defect evolution of silicon steel strip during rolling process was conducted on the base of GTN damage model,and then the results were compared with rolling experimental results.The results show that the edge...
薄带连铸取向硅钢的热轧孪生行为
薄带连铸流程下取向硅钢粗大λ晶粒(〈100〉//ND,normal direction)的“遗传”会导致磁性能恶化.为解决这一问题，针对取向硅钢的热轧孪生行为开展研究，结果表明：凝固组织粗大的取向硅钢在650℃热轧时可产生大量{112}〈111〉形变孪晶，这与具有高层错能的硅钢在较高温度下难以孪生变形的传统认知不同.热轧过程中复杂的应力状态降低了变形孪晶的取向依赖性，由于具有更高的储存能，孪晶界/孪晶界及孪晶界/晶界交叉点成为再结晶形核的优先位置，大大提高了常化过程中的再结晶率，受沿孪晶界应变分布及孪晶间距离的限制，沿孪晶界形核的再结晶晶粒通常呈“饼状”,最终形成以细小且取向漫散的再结晶晶粒为主的常化组织，消除了初始凝固组织中有害的粗大λ晶粒. In strip casting grain-oriented silicon steels, the inheritance of coarse λ grains(〈100〉//ND, normal direction) can deteriorate their magnetic properties. To solve the problem, twinning behaviors in strip casting grain-oriented silicon steels during hot rolling were investigated in this work. It is found that after rolling at 650 ℃, a number of {112}〈111〉deformation twins are formed in the coarse solidification microstructure of the steels, in contrast to the well-accepted view that it is diffic...
