宁波材料所在铁基纳米晶软磁合金研究方面取得新进展

中科院宁波材料技术与工程研究所沈宝龙课题组在前期探索发现的具有高饱和磁感应强度和良好软磁性能的FeSiBPCu合金基础上,对合金成分及纳米晶化工艺进行了进一步优化,成功研制出具有更优异性能的FeSiBPCu纳米晶软磁合金。该合金的纳米晶粒尺寸为15nm,其饱和磁感应强度达到1．8T,已接近于硅钢,矫顽力仅为1．1A／m,而铁损则远低于硅钢,在工频条件下（50Hz,1T）的铁损为0．22W／kg,分别是取向硅钢铁损（0．64w／kg）的三分之一,无取向硅钢铁损（2．0W／kg）的九分之一。     

轧制法制备低铁损高磁感6.4%(质量分数)硅钢及其织构演变

采用轧制法制备出具有低铁损高磁感0.23mm厚6.4%(质量分数)Si高硅钢。沿轧制方向的最终磁性能为B8=1.474 T,B50=1.714 T;P10/50=0.30W/kg,P15/50=0.88W/kg。利用X射线衍射及背散射电子衍射(EBSD)技术分析了高硅钢在轧制及退火过程中的织构演变过程。结果表明,通过采用大压下率热轧,确保热轧板次表层中产生更多的高斯织构,随后进行遗传;温轧板中粗大的晶粒有利于冷轧剪切带的形成;冷轧板经脱碳退火后生成强{210}〈001〉织构及次表层较强的高斯织构是在轧向上获得高磁感的原因,归因于其在{111}〈112〉冷轧形变晶粒内的剪切带优先形核并长大;最终退火后虽出现了随机取向,但以{310}〈001〉织构为代表的η织构得以保留并且增强,进一步提高了磁感。随着退火温度的升高及保温时间的延长,高硅钢薄板晶粒尺寸不断增大,铁损明显降低。     

含核壳异质结构6.5% Si高硅钢铁芯的制备与磁性能

以构建高磁感、低铁损、免轧制高硅电工钢铁芯为出发点,提出采用单辊甩带制备非晶铁硅合金薄带、微氧化法在铁硅合金粉末表面包覆高电阻率铁硅氧化物薄膜制备核壳异质结构高硅电工钢纳米粉末、放电等离子烧结快速成形制备颗粒间绝缘的高硅电工钢铁芯。研究了不同氧化包覆时间对SPS烧结试样密度、物相组成、微观结构和静磁性能的影响。研究表明,在氧化包覆5h烧结温度800℃工艺条件下,制备的6.5%Si高硅电工钢铁芯的静磁性能最佳,饱和磁化强度为128.84A.m2/kg、矫顽力为2.25kA/m、剩磁为3.47A.m2/kg。其饱和磁化强度与粉末压延法制备的高硅钢相当,但矫顽力降低了1/3。     

激光刻痕对取向硅钢铁损和磁畴的影响规律研究

激光刻痕是一种降低取向硅钢片铁损的有效方法。选取激光功率、扫描速度、激光频率、刻痕间距作为工艺变量,对取向硅钢片进行刻痕实验,并利用磁性能测试系统和磁畴观测仪研究了不同工艺参数对激光刻痕后取向硅钢铁损和磁畴的改善效果。结果表明,取向硅钢片的平均铁损降低率随激光功率和刻痕间距增大而先增大后减小,随激光频率和扫描速度增大而减小。经不同工艺参数刻痕后,硅钢片的磁畴宽度均有所减小,且磁畴宽度的变化规律与铁损降低率的变化规律相吻合。优化了取向硅钢片的激光刻痕工艺参数,利用此工艺刻痕后,取向硅钢片的平均铁损降低率达8%。     

Mn对高牌号无取向硅钢组织、织构及磁性能的影响

本文借助OM、EBSD和磁性能测量仪,研究了Mn对高牌号无取向硅钢组织、织构和磁性能的影响。结果表明,与0.2Mn相比,1.6Mn热轧板再结晶过程受到较大程度的抑制,这导致旋转立方织构强度明显增强。经920℃常化后,相较于热轧板,常化板组织明显改善,且基本保留了热轧板的织构组分,但添加1.6%Mn对常化板织构影响较小。930℃退火后,相较于0.2Mn, 1.6Mn成品板晶粒尺寸略大一些,同时不利的{111}织构含量几乎不变,有利的{100}织构含量降低,导致织构因子下降,因此磁感B_(5000)由1.683T降至1.644T。对于铁损,Mn含量增高导致铁损P_(1.5/50)由2.45 W/kg下降至2.35 W/kg,而高频铁损P_(1.0/400)则可能由于涡流损耗大幅降低,导致其从19.29 W/kg明显降至17.36 W/kg。     

多层喷射沉积颗粒增强铝基复合材料的研究现状与发展趋势

通过多层喷射沉积技术制备颗粒增强铝基复合材料,强化了冷却效果,能获得细小均匀的显微组织,优化复合材料中增强相的分布及其与基体的结合状态。本文综述了喷射沉积颗粒增强铝基复合材料的发展现状;介绍了多层喷射沉积技术的原理与工艺参数;概述了喷射沉积颗粒增强Al-Zn—Mg系、Al—Fe系与Al-Si系复合材料;并介绍喷射沉积颗粒增强铝基复合材料的致密化技术,着重介绍在小吨位设备上致密大块多孔材料的楔形压制工艺、外框限制轧制、陶粒包覆轧制工艺和热压后轧制工艺;展望了喷射沉积铝基复合材料的的发展趋势,认为增强颗粒与基体界面的结合强度有待进一步提高,提出了多层喷射沉积技术将朝在可编程控制下制备组织均匀、细小且致密度高的大尺寸坯料方向发展,而致密化技术也将朝小吨位设备制备大尺寸致密材料的方向发展,认为热压和楔形压制作为预致密方式能有效提高大尺寸喷射沉积坯料的成形能力,有利于进一步成形。     

喷射沉积8009/SiCP铝合金的陶粒轧制成形性能研究

针对喷射沉积铝合金板坯含有一定量的孔隙、直接轧制时易出现板坯表面横裂及边裂的问题,探讨了一种新型的准等静压轧制工艺-陶粒轧制.主要研究在陶粒轧制工艺过程中传压介质对喷射沉积8009/SiCP铝合金板坯轧制成形性能的影响.结果表明,在陶粒轧制过程中合理设计、选取及控制传压介质,避免了板坯轧制变形过程中裂纹的形成,有效地提高了喷射沉积铝合金板坯的轧制成形性能.     

喷射轧制钢/Al-Pb复合轴瓦带材的组织与性能

采用喷射轧制工艺制备了钢/Al-8.5Pb-4Si-Cu-0.5Sn复合轴瓦带材,分析了所制备材料的组织及性能.结果表明,用喷射轧制工艺制备的轴瓦合金Al-Si基体中分布有均匀细小的Pb相粒子,经过50%变形量的轧制和在320℃后续退火5h的处理,在复合轴瓦带材的界面处发生了合金元素的扩散,形成了良好的冶金结合层,界面强度高,剪切强度达到72MPa.用喷射轧制工艺制备的轴瓦合金具有良好的耐磨性能.     

Microstructure and properties os steelAl-Pb composite bearing plate prepared by spray forming and rolling

采用喷射轧制工艺制备了钢/Al-8.5Pb-4Si-Cu-0.5Sn复合轴瓦带材，分析了所制备材料的组织及性能。结果表明，喷射轧制工艺制备的轴瓦合金Al-Si基体中具有均匀细小的Pb相粒子分布，经过50%变形量的轧制及320℃，5小时的后续退火处理，复合轴瓦带材的界面处发生了合金元素的扩散，形成了良好的冶金结合层，界面强度高，剪切强度可以达到72MPa，制备的轴瓦合金耐磨性能良好。     

喷射轧制技术的研究进展

喷射轧制加工技术是一种金属半固态近净成形新技术。与铸轧、喷射沉积、铸锭冶金制备的材料相比,喷射轧制材料具有均匀细晶组织和优异综合性能。综述了近年来喷射轧制技术的理论研究,以及数值模拟等方面的研究进展。针对喷射轧制理论研究方面存在不够深入的问题,提出了借鉴喷射成形和双辊铸轧较为成熟的理论。采用实验研究和数值模拟相结合的方法,研究工艺参数对喷射轧制过程中液滴的动力学行为和热力学行为的影响,以及对材料的显微组织和力学性能的影响,探索喷射轧制的基本规律。最终预测了该技术能为金属加工业提供一种节能节材、短流程的板带材生产新途径的发展前景,对该技术及其过程原理的深入研究将形成金属半固态近终形加工的新理论。     

FeCuNbVSiB纳米晶软磁合金及其在电力电子技术领域中的应用

报道了新开发的Ｆｅ７３．２Ｃｕ０．８Ｎｂ２Ｖ１．５Ｓｉ１．５Ｂ１１纳米晶合金的主要磁性能：μ０≥８×１０＾４,ＢＳ＝１．４０Ｔ,Ｐ０．５／２０ｋ≤１９Ｗ／ｋｇ,Ｐ０．５／５０ｋ≤９０Ｗ／ｋｇ。以μ（ｋ）ｔ Ｐ０．５／２０ｋ为参数,研究了合金的温度稳定性。研究表明,与２５℃时全金性能相比,在－５０℃和＋５０℃时合金性能的相对变化率不超过５％。介绍了合金在中、高频功率变压器、传感器、电感器等电力电子技     

Kaltgewalztes Flachzeug aus unlegierten weichen Stählen — Nach DIN 1623 Blatt 1

Cold-Rolled Flat Products of Plain Carbon Mild Steel According to DIN 1623 Sheet 1 . Cold-rolled flat products of plain carbon mild steel and among the most important finished products made by iron and steel works and rolling mills as well as being among the most important semi-products for industrial manufacture. Metallurgical and rolling developments during the course of the last twenty years have resulted in considerable improvements in the main cold forming properties of sheet and strip. The chief demand made of manufacturers of cold-rolled flat products is for sheet and strip which has been fully annealed and rerolled for good cold formability. Because of the various stresses on materials in the different forming processes, it is difficult to make a reliable prediction from test results about the behaviour of the material during actual forming operations. The new edition of sheet 1 of DIN 1623 prescribes the conventional test methods and their results as regards ensuring cold formability. The Standard does not include the additional means of using numerical values for vertical anisotropy r, work hardening exponent n and the maximum drawing ratio (ßo)_max.     

热镀锌钢板用冷轧板退火工艺的确定

采用盐浴退火方法分别对牌号为SSGrade40,SSGrade33和SSGrade50的热镀锌钢板的冷轧硬卷进行了不同工艺的退火处理,研究了退火工艺对三种热镀锌钢板用冷轧板显微组织和力学性能的影响,以确定三种冷轧板的再结晶温度及最佳退火温度范围。结果表明：SSGrade40冷轧板的再结晶温度在720℃左右,退火温度在720℃较佳;SSGrade33冷轧板的再结晶温度在680℃左右,考虑到力学性能的稳定性,退火温度选择在720℃左右较佳;SSGrade50冷轧板的再结晶温度在700℃以上,为了保证其强度富余量和性能稳定性,退火温度选择在780℃左右较佳。     

Effect of reduction rate and annealing temperature on texture evolution and magnetic properties of used non-oriented silicon steel

This paper discusses the method of improving the magnetic properties of used silicon steel by cold rolling and annealing process with used non-oriented silicon steel as the object. The texture evolution and magnetic domain structure are also investigated. Experimental results show that the magnetic domain can be transformed vastly compared with the used silicon steel when the specimens are prepared through the same cold rolling and annealing conditions. The length of the magnetic wall and the density of magnetic domain per unit area are boosted, and the magnetic domain refinement is exceedingly apparent. Under the same annealing condition (at 950 °C for 5 min), the γ-fiber is gradually decreased to 6.6 % and the {110} recrystallization texture is gradually enhanced with increased reduction from 28.3 % to 40 %. The intensity of the Goss texture reaches a maximum of 22.2. For the cold rolling reduction of 34.3 %, the γ-fiber gradually decrease to 13.8 % and the {110} recrystallization texture is gradually enhanced with increase in the annealing temperature from 800 °C to 950 °C. Moreover, the intensity of Goss texture reaches 14. The sample prepared through 40 % reduction and annealing at 950 °C for 5 min exhibited the most desirable magnetic properties. The magnetic induction B₅₀ value of the specimen is increased by 0.052 T, and the core loss P_1.5/50 is reduced by 0.478 W/kg compared with the initial specimen.     

Model Transformer Evaluation of High-Permeability Grain-Oriented Electrical Steels

1. IntroductionThe demand for grain-oriented electrical steel asthe transformer core material having reduced iron losshajs been continuously growing for the general objective to achieve ever greater energy savings and globalenvironmental preservation. In line with this trend,efforts to reduce iron loss in steel sheets have been pursued both in hysteresis and eddy-current losses. Theformer has been improved mainly through metallurgical means such as achieving higher grain-orientationand reducin…     

Texture and magnetic properties of rapidly quenched Fe-6.5wt%Si ribbon

Rapidly quenched Fe-6.5wt%Si alloy has been fabricated as 2.5 cm wide ribbon using the planar flow casting process. The magnetic properties have been investigated for various heat treatment conditions. The relationship between core loss and exciting power vis-avis texture and microstructure of the as-cast and annealed ribbons is discussed. The best magnetic properties obtained-a core loss of 0.46 W/kg and an exciting power of 0.62 VA/kg at B = 1.0 T and f= 60 Hz-are considerably better than those for commercial nonoriented Fe- 3wt%Si steel, but inferior to those for commercial amorphous metallic glasses. The magnetic properties are isotropic in the plane of the ribbon. which makes this material attractive for applications in rotating devices.     

A Typical Failure Analysis of Medium Carbon Hot Rolled Strips

Medium carbon hot rolled steels are used for wide range of engineering applications. Normally, MC 55 (C: 0.51–0.60 wt.%) grade is used in fabricating various components for automobile and textile industries. Such high-end applications demand superior steel cleanliness to eliminate risk of cracking during cold rolling/forming operations. This article attempts to identify the origin of defects obtained during cold rolling. It has been established that higher Al (~0.06%) and N (~76 ppm) contents in the steel along with excessive segregation of carbon, and the presence of inclusions such as aluminium oxides and MnS were responsible for inadequate cold reducibility, causing crack formation in the sheet material.     

Spray forming of high density sheets

Porosity is one of the most important quality criteria of spray‐formed materials in the as‐sprayed condition. Typically, spray‐formed sheets have a porous rim close to the substrate and depending on the spray conditions cold or hot porosity may also be present in the core of the deposit. This porosity has to be removed or minimized to make further processing steps such as rolling, forging or extrusion possible. In this paper, the influence of both substrate temperature and deposit surface temperature on porosity in spray‐formed sheets is studied. For this purpose spray forming experiments (sheet size 1000 mm × 250 mm) were carried out using three different materials: aluminium‐bronze, tin‐bronze and a nitriding steel. For the copper‐base alloys preheated steel‐substrates with different temperatures were moved through a scanning spray cone. In the case of steel a ceramic substrate at room temperature was used. In addition to the variation of the substrate temperature, the gas to metal mass flow ratio (GMR) was varied to achieve different deposit surface temperatures. During the run the surface temperature in the deposition zone was measured using a scanning, multi‐wavelength pyrometer. Samples of the deposits were polished and rasterized by light microscopy. The local porosity was characterized by digital image analysis. The influence of the substrate temperature and the GMR on the porosity in the vicinity of the substrate is evaluated and discussed in detail. The impact of the deposit surface temperature on the porosity was analyzed and is discussed as well. It was found that the deposit surface temperature has a strong impact on porosity for spray‐formed sheets. Finally, experimental results were used to develop a new approach to predict the porosity in spray‐formed sheets. The results clearly show the dependence on material properties. This approach can be used to identify process parameters to generate high density sheets in the future.