降减剪切边缘损伤和毛刺的电工硅钢板材精密剪切加工研究

The shearing area damage and large burr of electrical steel sheet in the slitting and guillotining process can reduce the magnetic properties and increase the core loss. Aiming at the unique polycrystalline structure of electrician steel sheet whose grain diameter is in the range of tens of microns to several millimeters, a new precision technique named Quasi Zero Clearance Arranging Cutter (OZCAC) is proposed. The OZCAC precision technique can achieve the ordering of the plastic shearing deformation and the crack propagation of ductile fracture, and decrease the shearing area damage and burr of electrical steel sheet by means of optimizing the cutter’s edge shape and the clearance between the neighboring cutters, improving the blade edge sharpness of the cutter and enhancing wear resistance by applying composite coating, thus will reduce the core loss and improve the energy efficiency. Some research methods, such as slitting and guillotining experiments, shearing force detection, processing observation and shear surface characteristic analysis, will be conducted to investigate the influence of processing parameters on breaking of inorganic insulation on the sheet metal surface, elastic-plastic deformation, ductile fracture, burr formation and shearing area damage, and to build the relationships between the processing parameters and the slitting and guillotining quality of electrical steel sheet. Finite element analysis software DEFORM will be applied to simulate and optimize the slitting and guillotining process of electrical steel sheet, and a model with a pair of cutter will be built to study the stress strain state of material, transgranular slipping of polycrystalline grain and micro-crack growth and propagation paths, then optimize the proportion between plastic shear and ductile fracture on the shear surface. It is expected to achieve precision technique and method with lower shearing area damage and burr for electrical steel sheet.

电工硅钢板材剪切加工的边缘损伤和过大毛刺会使其磁性能下降铁芯损耗增大，针对电工硅钢晶粒直径达到数十微米乃至数毫米的独特多晶体晶粒结构，提出准零侧隙组刀精密剪切加工新工艺，通过优化刀具刃型和组刀侧隙、提高刃口锋锐度、利用复合涂层改善刀具耐磨性等手段控制剪切塑性变形与韧性断裂裂纹扩展有序化，降减剪切边缘损伤和毛刺，达到减少磁性能损失降低铁芯损耗提高能源效率目的。采用加工实验、剪切力检测、微观过程观察、分断面特征分析等方法研究加工参数对电工硅钢板材剪切加工中表面无机绝缘层碎断、材料弹塑性变形、韧性断裂、毛刺形成、剪切边缘损伤的影响，探讨加工效果与加工过程特征参量的关系。应用DEFORM有限元软件建立双刃剪切作用模型，研究剪切过程中材料应力应变状态、多晶体晶粒穿晶剪切滑移及微裂纹萌生和扩展路径，优化分断面塑性剪切与韧性断裂比例，获得降减剪切边缘损伤和毛刺的电工硅钢板材精密剪切加工理论、方法和技术。

电工硅钢是电力、电讯和军事工业不可缺少的重要软磁合金和功能材料，其剪切成型加工质量会直接影响磁性能和铁芯损耗。项目通过研究新剪切工艺、控制剪切变形过程应力应变状态、实现裂纹扩展有序化，优化剪切工艺参数、设计刀具几何刃型并优化制造工艺提高刃口锋锐度、利用复合涂层改善耐磨性等手段，降减电工硅钢的剪切边缘损伤和毛刺，达到保持磁性能、减少铁芯损耗、提高能源效率的目的。搭建了电工硅钢精密剪切的实时测力平台，系统实验研究了不同材质、板厚及工艺参数的剪切力特性，探索了剪切断面特征与剪切力的关系，提出了电工硅钢板材剪切力理论计算修正公式。针对电工硅钢粗大晶粒和各向异性的独特材料特征，采用有限元分析方法基于晶体塑性学研究了考虑晶粒变形的电工硅钢剪切过程中的材料变形和断裂过程及各变形阶段的应力应变状态及分布。实验研究了不同应力状态的板材变形和断裂状态，考察了剪切过程中晶粒尺寸效应、工艺参数对剪切断面质量、组织流动、多晶体晶粒变化、材料加工硬化、剪切力等的影响规律及其作用机理，揭示了电工硅钢板材“弹性变形—塑性剪切滑移—韧性断裂分离”的连续变形过程及其微观机理，探究了剪切边缘损伤和毛刺形成机理及其控制机制。采用横剪骤停方法研究了不同剪切阶段的电工硅钢表面无机绝缘层的碎断形态、破损过程，深入研究了剪切边缘区域的剪切变形和加工硬化等对电工硅钢磁性能的影响，系统研究了剪切工艺参数对无机绝缘层破损、板材磁性能的影响规律，基于系统的工艺实验研究优化了剪切加工工艺参数，实现了降减剪切边缘损伤、毛刺和磁性能损伤的电工硅钢板材精密剪切加工。系统跟踪研究了剪切刀具的磨损过程、形态及磨损机理，探讨了刀具磨损对变形过程、剪切力、断面质量及剪切边缘损伤的影响规律，在此基础上制备了AlTiN涂层刀具，系统研究了涂层刀具的力学性能、剪切质量及使用寿命，实验证明涂层刀具能够显著提高耐磨性，大幅提高刀具使用寿命，并降减了电工硅钢板材的剪切边缘损伤和毛刺，为剪切刀具研发提供了有益参考。项目研究成果有效支撑了高性能电磁铁芯制造、绿色节能变压器等电力设备的发展。