两次冷轧法轧制的无取向硅钢{001}〈210〉织构的发展

在元取向硅钢中，{001}〈210〉织构具有良好的磁性，而采用两次冷轧法（中间退火温度为640℃）能够坩强这种织构。利用电子背散射图形（EBSP），测量退火过程中亚擞织构的变化来研究两次冷轧法生产的无取向电工钢{001}〈210〉奴构的形成机理。中间退火钢板的再结晶份数为60％，主要由〈111〉／／ND小等轴再结晶晶粒和〈110〉／／RD伸长变形晶粒组成．在最终退火期间，再结晶晶粒〈111〉／／ND方向的长大被抑制。晶粒在{001}晶面〈210〉晶向上的长大使〈111〉／／ND方向的再结晶晶粒被消耗。这是由于再结晶晶粒中第二次冷轧在〈111〉／／ND方向引入的应变所造成的。所以，最终退火钢板的结构主要为{001}〈210〉织构。     

Correlation Between Pre-annealing Temperature and {110}〈001〉 Annealing Texture in C- and Al-Free Fe-3 Pct Si-0.1 Pct Mn-0.002 Pct S Electrical Steel

In C- and Al-free electrical steel, the increase in primary grain size with increasing pre-annealing temperature causes the transition in annealing texture after final annealing from {110} + {100} to {110}. The strip pre-annealed at 1073 K (800 °C) shows a low magnetic induction B₈(T) of 1.784 T after final annealing. The strip pre-annealed at 1223 K (950 °C) shows a sharp {110}〈001〉 Goss texture, producing a high magnetic induction B₈(T) of 1.914 T comparable to that of the conventional electrical steels.     

Formation of Edge Crack in 1.4%Si Non-oriented Electrical Steel during Hot Rolling简

Microstructure evolution, dynamic recrystallization, high temperature oxidation and hot ductility of 1.4 % Si non-oriented electrical steel sheets were investigated to reduce edge cracking. The causes of cracking were found to be coarse as-cast microstructure, grain boundary oxidation in reheating furnace, lack of dynamic recrystallization during hot rolling and increase of temperature, resulting in reduced hot ductility in strip edge region. Countermeas- ures against the edge crack are proposed accordingly. Lowering reheating temperature and reducing holding time re- duced oxidation and decarburization. Hot charging temperature was increased to decrease reheating temperature. And using an edger can refine microstructure in strip edge region. Finally, edge heater can be added to increase edge re- gion formability by inducing dynamic reerystallization and ductility by increasing temperature.     

Observation of 〈001〉 dislocations and a mechanism for transgranular fracture on {001} in FeAl

Transmission electron microscopy of iron-rich, B2-structure, FeAl alloys which had been compressed at room temperature revealed the presence of 〈001〉 dislocations, in addition to APB-coupled 〈111〉 dislocations which are normally observed at room temperature. It appears that the 〈001〉 dislocations form through the interaction of the 〈111〉 dislocations. This reaction to produce 〈001〉 dislocations is outlined and shown to be energetically favorable. The production of these 〈001〉 dislocations on {100} planes is suggested to be a cause of transgranular cleavage on {100} in B2 alloys deforming by 〈100〉 slip.     

Effect of temperature and shear direction on yield stress by {11\bar 22}〈\overline {11} 23〉 slip in HCP metals23〉 slip in HCP metals

The yield shear stress τ _y due to {11 $\bar 2$ 2}〈 $\overline {11} $ 23〉 second-order pyramidal slip system in cadmium, zinc, and magnesium hcp crystals increased with increasing temperature. This result is interpreted by two thermally activated processes as follows: (1) the dissociation of a (c+a) edge dislocation with a Burgers vector of 1/3〈 $\overline {11} $ 23〉 into a c sessile dislocation and an a glissile basal dislocation, and the subsequent immobilization of the (c+a) edge dislocation; (2) consequently, the double-cross slip of (c+a) screw dislocations must be activated thermally by an increment of applied stress to increase propagation velocity of slip band width. Moreover, τ _y is affected strongly by a direction of applied shear force due to second-order pyramidal slip in zinc as well as in cadmium. The anomalous behaviors of yielding would be caused by the nonsymmetrical core structure of the (c + a) dislocation due to the lattice heterogeneity in hcp metals.     

取向硅钢中高斯晶粒异常长大选择性行为

对CGO取向硅钢二次再结晶中断实验进行了研究,发现二次再结晶升温过程中,仅在异常长大开始前,高斯晶粒尺寸明显大于其他晶粒,且不同取向晶粒的数量与脱碳退火时的特征一致.高斯晶粒晶界上MnS等抑制剂的优先粗化使高斯晶粒能够率先发生异常长大,且只有晶界弯曲严重或经过很小的生长几个晶粒就能合并的高斯晶粒才能成为二次晶核.在高斯晶粒异常长大过程中,晶界形貌参差不齐,呈岛屿状.研究表明:高斯晶粒独特的生长方式,可能是使二次再结晶能很快完成的原因.     

在动态热处理条件下对取向电工钢二次再结晶的研究

对应用动态加热进行短时温度退火的取向电工钢进行了二次再结晶研究。所进行研究的实验用取向电工钢是经过终冷轧和后续罩式退火后的一条工业化生产线生产的。研究结果表明,运用短时热处理条件可引起研究钢完全的异常晶粒长大。在实验室处理的材料的织构和金相组织与工业化生产的经过终退火而获得的相同的取向电工钢类似。但是,在实验室处理的取向电工钢的二次再结晶的矩阵中可观测到"寄生"晶粒。从磁性观点看,这些"寄生"晶粒含有不理想的{111}取向织构。     

取向硅钢二次再结晶机理研究的进展

取向硅钢二次再结晶的机理是涉及到材料的成分及热轧、冷轧、初次再结晶退火和最终高温退火等一系列工艺过程的复杂问题。几十年来,许多冶金工作者曾在这一领域进行了大量的研究工作,并取得了很大进展。近年来,由于实验技术的进步,更加深了对这一问题的认识。本文在对有关的早期工作进行简要回顾总结的基础上,重点对近年来的一些最新研究结果以及提出的新理论做了较为系统的介绍。     

Effect of Hot Band Annealing on Magnetic Properties in 3% Si Grain‐oriented Electrical Steels

Hot band annealing is known to be a prerequisite for good magnetic properties irrespective of manufacturing methods in grain‐oriented Fe‐3 wt.% Si electrical steels. In this study, the effects of hot band annealing on magnetic properties were investigated in 3% grain‐oriented electrical steels of low soluble AI contents and one‐stage cold rolling. Microstructure and precipitate distribution were compared with hot band annealing conditions. Secondary recrystallization behaviour with hot band annealing condition was also discussed.