Effects of calcium treatment on non-metallic inclusions and magnetic properties of non-oriented silicon steel sheets

Based on the industrial production of non-oriented silicon steel,calcium treatment by CaSi wire feeding during the RH refining process was studied. The thermodynamics of CaS inclusion formation was analyzed, and the morphology and the size distribution were observed. Furthermore, the change in inclusion characteristics after calcium treatment and the effect of calcium treatment on magnetic properties were discussed. The results show that the formation of MnS and A1N inclusions were restrained, and the aggregating, floating and removing of microinclusions after calcium treatment were effectively promoted. The cleanliness of liquid steel was obviously increased. The main type of inclusions was single phase of CaO, with some complex inclusions composed of CaO, SiO2 and MgO. No CaS inclusion was observed after an appropriate calcium treatment. The size of all inclusions was distributed in the range of 2 - 20 μm, and the number was about 1.8 × 10^5/mm3. In addition, as an increasing amount of calcium was added,the core loss gradually decreased to a stable level, and the magnetic induction decreased quickly after a slow increase. The optimal calcium treatment mode depends on the chemical composition of steel.

Control of nonmetallic inclusions of non-oriented silicon steel sheets by the rare earth treatment

Based on the industrial production of non-oriented silicon steel, the rare earth （RE） treatment during the Ruhrstahl Heraeus （RH） refining process was studied. The morphology and the size distribution were observed for the steel specimens treated with different RE treatment conditions. Furthermore, the formation and change of the nonmetallic inclusion characteristics of finished steel sheets after the RE treatment were discussed. The results have shown that in the present work,the suitable RE metal additions are 0.6 -0.9 kg/t steel. After the suitable RE treatment,the formation of AIN and MnS inclusions were restrained, and the aggregation, flotation and removal of nonmetallic inclusions were efficiently promoted and the cleanliness of liquid steel was significantly increased. Meanwhile, the total oxygen concentration reached the minimum value and thle desulfurization efficiency was optimal ,and the type of main inclusions was approximately spherical or elliptical spherical RE radicle inclusions whose size was relatively large.

Characteristics and application of Baosteel's Cr-free ultrathick J coat for non-oriented silicon steel sheets

Baosteel＇ s Cr-free ultrathick J coat for non-oriented silicon steel sheets has excellent insulation performance and has been successfully applied to middle and large scale electric power trains and wind electric power devices, which have stricter requirements than typical for coat insulation. In this paper, the characteristics and application of this type of coating for non-oriented silicon steel sheets were described in detail.

Manufacture and application of a Cr-free insulation coat for non-oriented silicon steel sheets

The manufacturing techniques of a Cr-free coat for non-oriented silicon steel sheets with excellent magnetic properties were developed. The ingredients of the coat mainly include phosphate, epoxy resin, an amine solidified agent and water. Through the adjustment of ingredients, superior adhesiveness, corrosion-resistance performance, welding performance and stamping preformance have been obtained. Thus ,the non-oriented silicon steel sheets with the above Cr-free coat have been used successfully in the fields of compressors ,transformers, and small and medium motors.

Transverse thickness difference control technology for non-oriented silicon steel

Transverse thickness difference is an important quality index of non-oriented silicon steel strips. In order to fulfill users＇ accuracy requirements on the transverse thickness of silicon steel and improve the production yield, the factors influencing transverse thickness difference were analyzed. Then the work roll shape, control strategy and incoming hot-rolled strips were optimized. Since the optimization measures were implemented in the actual production, the thickness difference of non-oriented silicon steel has been reduced greatly and fulfilled the requirements placed by users. These measures have achieved remarkable effects.

取向硅钢热轧板中纤维织构及Goss织构的形成和演变

在热轧过程中,取向硅钢热轧板形成了不均匀的微观组织和织构梯度,其中热轧板表层和次表层中的Goss织构对取向硅钢的磁性能有重要影响。因此,热轧板微观组织和织构沿厚度方向的形成和演变,特别是Goss织构的形成,仍然是一个值得讨论的课题。为了研究热轧板组织和织构的形成及其演变,使用光学显微镜和扫描电镜(SEM-EBSD)观察了热轧板不同厚度层(表层、次表层和中心层)组织,研究了热轧板组织形貌沿厚度方向的演变,并使用XRD测量了热轧板各厚度层(从表层s=1到中心层s=0)的宏观织构。结果表明,在高剪切力的作用下,热轧板表层s=1形成了大量等轴晶粒(晶粒长宽比为1.0~1.5)和具有一定随机性的织构。表层以下,随着剪切力从表层向中心层逐渐减小,等轴晶粒(晶粒长宽比为1.0~1.5)占比逐渐降低,再结晶晶粒的晶粒长宽比沿着厚度方向逐渐增大,再结晶晶粒形状倾向于沿轧向延伸和呈不规则状。最后,在中心层s=0中,一些大尺寸再结晶晶粒的晶粒长宽比可以达到3.0~6.5。在压缩力和沿厚度方向逐渐减小的剪切力的共同作用下,热轧板次表层s=0.5~0.9形成由众多特定取向组成的纤维织构,而中心层s=0~0.4形成典型的α纤维织构,纤维织构中的一些典型的特定位向包括{100}〈011〉、{112}〈111〉、{110}〈112〉、{213}〈364〉、{441}〈104〉和{110}〈100〉Goss。热轧板次表层s=0.5~0.9中的纤维织构沿厚度方向逐渐演变,并且在次表层s=0.5中有稳定的Goss织构形成。然而,次表层s=0.5中形成的高强度的Goss织构,而次表层中形成的Goss织构只是纤维织构的一小部分。

大型核电汽轮发电机磁屏蔽用厚硅钢板的应用特性研究

磁屏蔽压板是大型核电汽轮发电机的重要部件,直接影响到机组的发电效率及运行稳定性,同时对于保障机组安全可靠运行具有重要的意义。厚硅钢板作为磁屏蔽压板的原料,要求其在具有优异电磁性能的同时具备一定的强度。然而磁屏蔽用硅钢板厚度大、硅含量高、轧制易开裂的特点导致其生产难度较大,此前一直由国外进口,未能实现国内生产。本文介绍了核电磁屏蔽用厚硅钢板的国产化研究,主要包括成分设计、工艺路线制定与优化以及应用特性研究。国产厚硅钢板与进口厚硅钢板的一系列对比表明,国产厚硅钢板能够满足大型核电汽轮发电机的使用要求,并在化学成分均匀性以及电磁性能的表现上均优于进口钢板。

热轧板厚度对高牌号无取向硅钢磁性能的影响

基于高牌号无取向硅钢现场生产实验,将相同炉次的连铸板坯热轧至不同厚度(2.1,2.3,2.6 mm)的板卷,经常化均热工艺调控,获得晶粒较为均匀的常化板组织,再经85.7%~88.5%压下率冷轧,得到相同厚度(0.3 mm)的冷轧板,最终采用相同的退火工艺得到退火板;结合组织、织构和磁性能的相关检测分析,研究热轧板增厚对高牌号无取向硅钢产品磁性能的影响。结果表明:随高牌号无取向硅钢热轧板厚度的增加(在2.1~2.6 mm范围,即冷轧压下率降低),退火板组织中{111}晶粒占比提高,γ纤维织构强度逐渐增强,织构发生恶化;随热轧板厚度的增加,磁性能中铁损P_(1.0/400)线性增加,磁感强度B_(50)线性降低。热轧板厚度由2.1 mm增至2.3 mm时,P_(1.0/400)平均恶化0.20 W/kg,P_(1.5/50)平均恶化0.04 W/kg,B_(50)平均恶化0.005 T;热轧板厚度由2.3 mm增至2.6 mm时,P_(1.0/400)平均恶化0.24 W/kg,P_(1.5/50)平均恶化0.04 W/kg,B_(50)平均恶化0.009 T。

Effect of lanthanum on recrystallization behavior of non-oriented silicon steel

Non-oriented silicon steels containing different mass fractions of lanthanum were prepared using a high-frequency suspended furnace.Microstructures were observed by a metallographic microscope and micro-orientations were analyzed by a scanning electron microscope（SEM）.The results showed that at the annealing temperature of 870℃,recrystallization started at 90 s and completed at 120 s during annealing.Without lanthanum,no matter Cube or {111 }110 grains,recrystallized grains nucleated mainly in deformed {111}110 and {113}031 grains.With lanthanum,however,they nucleated in the deformed {110} and {112}132grains.This indicated that addition of lanthanum changed the micro-orientation relationship between new grains and the matrix.

Recrystallization texture development in rare-earth(RE)-doped non-oriented silicon steel

High-grade non-oriented silicon steel with higher permeability and lower core loss has become the pursed target with the rapid developnient of electrical machines.The effects of rare-earth(RE)element on recrystallization texture in RE-doped Fe-3.1 wt.%Si-1.2 wt.%Al non-oriented silicon steel were investigated by macro-and micro-texture analyses.Nonlinear variation of recrystallization texture with RE element content was observed.In the competition among main recrystallization texture components,favorable{113}<361>and X fiber(<001>//ND)are strengthened and unfavorable y fiber is evidently decreased by the addition of RE element,whereas the effect of RE element is reversed by excess RE element.The recrystallization texture development is determined by RE-affected nucleation and grain growth in terms of grain boundary migration related to segregation and inclusion.The properly inhibited grain boundary mobility can promote favorable recrystallization texture by the improved nucleation and efficient grain growth.

Significant effect of as-cast microstructure on texture evolution and magnetic properties of strip cast non-oriented silicon steel

In this study, two types of as-cast microstructure produced by strip casting were cold rolled and annealed to investigate the effect of initial microstructure on the textural evolution and magnetic properties of non-oriented silicon steel. The results indicated that the cold-rolled sheets of coarse-grained strip with pronounced {100} components exhibited stronger 入 fiber(<100>//ND) and weaker γ fiber(<111>//ND)texture as composed to the fine-grained strip with strong Goss({110}(001)) texture. After annealing, the former was dominated by η fiber(<001>//RD) texture with a peak at {110}<001)orientation, while the latter consisted of strong {111}(112) and relatively weak {110}(001) texture. In addition, a number of precipitates of size ～30-150 nm restricted the grain growth during annealing, resulting in recrystallization of grain size of ～46 μm in the coarse-grained specimen and ～41μm in the fine-grained specimen.Ultimately, higher magnetic induction(～1.72 T) and lower core loss(～4.04 W/kg) were obtained in the final annealed sheets of coarse-grained strip with strong {100} texture.

采用基准模型的导磁钢板及取向硅钢叠片的电磁特性

为了研究电力变压器内由导磁钢板和取向硅钢片组成的结构件在实际工作状态下的电磁特性,基于Problem21基准族中的Model B及Model M1,考察不同激励方式下导磁钢板及取向硅钢片的损耗和磁通的分布,研究不同激励源之间的交叉作用对导磁钢板和取向硅钢片特性的影响,提出解决计算三维非线性和各向异性涡流问题的实用措施,不同激励方式下铁损和磁通的计算结果和测量结果具有较好一致性,所得结果和结论有助于通过优化设计来提高电力变压器的性能指标。

无取向硅钢片在电力变压器磁屏蔽中的应用

为研究无取向硅钢片在电力变压器磁屏蔽中的适用性,文中基于国际TEAM Problem 21基准族下的磁屏蔽基准模型P21c-M1和P21-M1,对在不同激励条件下无取向硅钢片制成的磁屏蔽的损耗特性和磁通分布特征进行研究,并与传统电力变压器普遍采用的取向磁屏蔽的磁性能进行对比分析。研究结果表明,由无取向硅钢片制成的无取向磁屏蔽对模拟电力变压器油箱壁的导磁钢板的屏蔽效果和取向硅钢片制成的取向磁屏蔽的屏蔽效果基本相同,且价格更为低廉。同时,基于结构件中杂散损耗的计算问题,提出了一种测量与仿真相结合的方法,通过与传统杂散损耗测量方法的对比,验证了该杂散损耗计算方法的有效性。

硅钢片自动叠片机的研究与设计

互感器用途广泛,市场需求量巨大,其内部的铁芯是由硅钢片叠加而成,目前,国内这一叠片工序靠人工完成,劳动量大,生产效率低.硅钢片自动叠片机的研发设计可以实现JSZW3-3、6、10型互感器硅钢片的自动叠放,提高了生产效率,保证了产品质量.本自动叠片机采用PLC控制的全气动传动方式,根据互感器的叠片工艺要求实现不同硅钢片的自动吸片和摆放,叠片效率是手工叠片的（2～3）倍.通过对自动叠片机的阐述介绍了叠片机的主要组成机构、工作过程及主要机构的设计.

硅钢在连续退火机组浪形缺陷的控制

为了消除硅钢在连续退火机组产生的浪形缺陷,对浪形缺陷产生的主要原因进行了分析。制定了相应控制措施,对炉内带钢张力、冷却段输出、碳套辊与带钢的同步性、无氧化炉燃烧状态等参数进行了调整;在生产组织上安排高低牌号宽窄规格穿插生产、定期更换碳套辊等,实施后效果明显。

无取向立式磁屏蔽的性能分析和实验研究

本文基于P21c-M1磁屏蔽模型,对工频下不同电流激励无取向立式磁屏蔽和取向立式磁屏蔽的屏蔽效果进行对比分析,研究无取向磁屏蔽在变压器磁屏蔽中的适用性。本研究中,采用激励线圈精确建模的方式,从总损耗中分离出激励线圈负载损耗,从而得到较为准确的磁屏蔽构件的损耗值。实验和仿真结果表明,在相同电流激励下,由于两种硅钢片的磁性能差异,无取向立式磁屏蔽的屏蔽效果相较于取向立式磁屏蔽有微小的差异。

低温板坯加热取向3%硅钢热轧板的研究

研究的两种取向硅钢(%:No1-0.042C、3.16Si、0.009Al、0.07Mn、0.50Cu、0.015S、0.0084N和No2-0.040C、3.20Si、0.014Al、0.22Mn、0.49Cu、0.016S、0.008 2N)由50 kg真空感应炉冶炼,锻成(mm)350×120×35板坯,经1 250℃30 min加热,开轧温度1 100℃,5道次热轧成2.3 mm板,终轧温度950～1 000℃。实验结果表明,两热轧板沿板厚方向存在组织和织构的不均匀性,热轧板次表层为再结晶组织,有较强的Goss织构组分;中心层为形变组织,具有典型的形变织构。含0.22%Mn的No2钢次表层{110}〈001〉织构组分比含0.07%Mn的No1钢弱,中心层{001}〈110〉织构组分大大强于0.07%Mn No1钢,导致两者磁性能差异,0.22%Mn No2钢磁感应强度(B_(800))和铁损(P_(1.7/50))分别为1.87 T和1.24 W/kg,0.07%Mn No1钢分别为1.88 T和1.18 W/kg。

27SiMn钢化学镀Ni-P、Ni-Ce-P对比研究

研究了27SiMn钢上化学镀Ni-P、Ni-Ce-P的工艺条件,以及所得镀层的组织形貌和性能。结果表明,稀土元素Ce使镀层表面金属胞状颗粒细小致密、有一定的晶化趋势,并使镀层中产生新相Ce_6Ni_6P_(17)和Ce_2Ni_(12)P_7;无润滑条件及润滑条件下,Ni-Ce-P镀层的粘着磨损性能分别是退火基体的8.55倍和1.78倍,是Ni-P合金镀层的7.50倍和1.67倍;在5%(质量分数)的H_2SO_4、NaOH和NaCl腐蚀液中,Ni-Ce-P镀层耐蚀性分别是Ni-P镀层的1.72、1.46和1.10倍,是基体的21.52、1.82倍和1.28倍。

无取向低牌号硅钢片横向厚差的研究

针对武汉钢铁公司无取向低牌号硅钢产品横向厚度差较大 ,成材率低等问题 ,从热轧原料横向厚度函数、板形函数和金属横向流动函数分析了影响钢板横向厚度精度的主要因素 ,从而可以确定热轧来料凸度及轧制参数 。

高牌号无取向硅钢CSP流程铸坯及热轧板的组织和夹杂物分析

2.9 mm热轧3%Si高牌号无取向硅钢板(/%:0.004 6C、3.04Si、0.32Mn、0.49Als、0.004S、0.013P、0.0042N)由CSP(Compact Strip Production紧凑式带材生产线)流程:120 t BOF-70 mm CC-热轧工艺生产。热轧终轧温度872℃,卷取温度683℃。铸坯及热轧板的组织和夹杂物的分析结果表明,铸坯组织为典型的贯穿柱状晶组织;热轧板边部为再结晶组织,中部为纤维组织带有少量再结晶晶粒;高牌号无取向硅钢的主要夹杂物为铸坯-Al_2O_3,AlN和Cu_2S+MnS;热轧板-Al_2O_3,AlN,AIN+MnS和Cu_2S+MnS。