再结晶及低温时效对Fe-6.5wt%Si薄板磁性能的影响

观察了高硅钢温轧板再结晶及低温时效过程中轧向和横向磁性能的差异及变化,通过取向分布函数、光学显微及X射线慢速扫描分析了织构、晶粒尺寸以及有序相的析出对铁损及不同磁场下磁感应强度的影响。结果表明,高硅钢虽然具有低的磁晶各向异性,织构仍是决定磁感值的关键因素,优化织构还可降低铁损。D03有序相的析出可降低饱和磁致伸缩系数,有益于降低低频铁损值,但其作用相比晶粒尺寸较小。退火后慢冷过程中依次发生B2及D03有序化,磁感B50的降低应是慢冷导致B2有序化及其有序度升高所致。等温时效过程以D03有序化为主,由于D03相在B2相中析出,时效过程中磁感没有变化。     

电力变压器用高磁感取向硅钢的发展及应用

阐述了国内外高磁感取向硅钢的生产研究水平与发展趋势,包括通过提高高斯晶粒取向度、细化磁畴、涂覆张力涂层、减薄钢片厚度进一步降低铁损以及低温加热技术和短流程技术新工艺。分析高磁感取向硅钢在我国大型电力变压器上的应用情况,结果表明,发展更薄规格高磁感、低铁损、低磁致伸缩取向硅钢可为大型变压器的安全性、节能性及环保性提供有效保障。     

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。     

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。     

退火张力对无取向硅钢再结晶织构和磁性能的影响

采用取向分布函数(ODF)分析了无取向电工钢冷轧板施加不同张力时再结晶退火后组织织构的变化。结果表明,随着退火张力的增加,再结晶晶粒尺寸逐渐增大,当退火张力为4 MPa时,晶粒平均直径达最大值75μm,且尺寸均匀,Goss织构和立方织构组分也增强,其铁损P_(1.5/50)降低到4.34 W·kg~(-1),同时磁感B50升至1.684T;当张力增加到6 MPa时,晶粒直径减小至40μm,{110}〈001〉和{001}〈100〉织构组分减弱,γ线织构组分明显增强,磁性能恶化。     

晶粒取向对冷轧无取向硅钢磁时效的影响

研究了含碳量约3.0×10-5的50W700型号冷轧无取向硅钢板织构与磁时效的关系。200℃、24h的时效实验表明,渗碳体的时效析出阻碍磁畴壁的移动,导致试样铁损升高。磁化时180°磁畴畴壁的驱动力与硅钢板织构有密切关系,〈100〉平行于外磁场方向的织构有利于减小磁时效导致的铁损增幅,降低钢板的磁时效效应。     

取向硅钢常化及其对二次再结晶影响的研究进展

取向硅钢是重要的铁芯材料,而常化是目前生产高磁感取向硅钢不可或缺的工业生产工序,它可以调整热轧板的组织、织构和抑制剂析出从而改善硅钢磁性能。本文综述了取向硅钢热轧与常化组织的遗传性规律与常化过程中抑制剂的演变规律,重点讨论了常化对初次再结晶和二次再结晶组织与织构的影响规律,指出常化组织中细小γ-晶粒群有利于二次再结晶,而大的变形α-晶粒与λ-晶粒不利于二次再结晶。最后针对低温加热渗氮型高磁感取向硅钢推荐了能最优化磁性能的三段式常化工艺及其参数。而如何在保证获得同等织构组分与抑制剂含量的基础上进一步简化工艺以及常化工艺在薄板坯连铸连轧和薄带连铸生产取向硅钢中的合理应用将是未来常化发展的重点方向。     

退火张力对无取向硅钢再结晶织构和磁性能的影响

采用取向分布函数(ODF)分析了无取向电工钢冷轧板施加不同张力时再结晶退火后组织织构的变化.结果表明,随着退火张力的增加,再结晶晶粒尺寸逐渐增大,当退火张力为4 MPa时,晶粒平均直径达最大值75 μm,且尺寸均匀,Cross织构和立方织构组分也增强,其铁损P1.5/50降低到4.34 W· kg-1,同时磁感Bs.升至1.684 T;当张力增加到6 MPa时,晶粒直径减小至40 μm,{110}<001>和{001}<100>织构组分减弱,γ线织构组分明显增强,磁性能恶化.     

退火温度和时间对用电沉积法制备的高硅钢性能的影响

研究了退火温度和退火时间对电沉积硅钢试样中的断面层组织、硅在试样中的分布情况、织构分布和磁性能的影响。结果表明:退火温度为1000℃、退火时间为210 min时得到的试样晶粒分布均匀、硅在试样中分布均匀、硅平均浓度为6.3715%(接近6.5%)。试样的织构分析及磁性能检测的结果表明,在较高温度下延长退火时间可增加{100}和{110}面织构,降低铁损,所得试样的磁性能较为良好。     

银薄膜织构变化的定量研究

利用X射线衍射(XRD)织构分析技术研究了未退火及在400℃温度条件下经4h真空退火处理后的银薄膜织构。结果表明，银薄膜主要存在(111)和(100)面织构组份。银沉积薄膜(未退火)中(111)取向的晶粒多于(100)取向的晶粒。经退火处理后的硅基银薄膜表现更强的(111)和(100)面织构，而且(111)和(100)取向的晶粒数量基本相当。用表面能和应变能各向异性驱动晶粒生长的机理对此给予了解释。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.