航空接头锻件等温锻压成形工艺

为了提高航空锻件的综合性能,通过等温锻压工艺研究了航空接头锻件的成形过程,采用Deform3D有限元软件对高筋薄壁铝合金航空接头锻件的锻压成形工艺进行了仿真研究,在实验室油压机上开展了缩比(1∶5)锻件的成形工艺实验.研究结果表明:在坯料与模具温度均为450℃、成形速度为0.1 mm/s的等温模锻工艺下,材料变形抗力比常规热模锻降低70%,材料在模腔中的流动性提高,锻件充填完好,锻件变形均匀,应力集中降低;等温锻造工艺可使锻件获得流线顺畅、晶粒细小、力学性能优良的纤维组织,避免了热模锻易出现的涡流、折叠、穿流、充填不满等锻造缺陷;仿真与实验结果吻合,为航空接头锻件锻压成形工艺的制订提供了依据.     

铝合金液态模锻的应用及发展

叙述了铝合金液态模锻成形的工艺实质、方法及其特点。阐述了铝合金液态模锻工艺的优点。介绍了液态模锻成形轿车零件的应用实例,指出了铸造技术和模锻技术有机结合成先进的液态模锻成形工艺是一种行之有效的新技术。     

高轮毂齿轮毛坯的模锻成形工艺及模具设计

通过对高轮轮毂齿轮的结构进行分析,制定出该锻件锻造成形的工艺流程,阐述了模锻工步、型腔的设计及模锻操作方法,实现了在3150t热模锻压力机上锻造生产。     

精密锻造成形技术在我国的应用

简要介绍了精密锻造成形技术的发展概况及主要应用领域,列举了大量的工程应用实例来阐明冷锻成形、温锻成形、闭塞锻造成形、精密热模锻成形、复合成形、等温锻造成形等精密锻造成形工艺在我国的应用情况.     

客车常用锻件锤上模锻CAPP系统的开发

介绍了以Visual Basic 为开发平台,以SOLIDWORKS为图形工具的锤上模锻CAPP系统,系统的使用者只需输入零件几何参数,即可自动进行冷、热锻件及模锻工艺的设计,从而彻底克服了传统模锻工艺设计的缺点.     

精密锻造技术的研究现状及发展趋势

综述了精密锻造成形技术的研究与应用现状,介绍了冷精锻、热精锻、温精锻及复合精锻工艺的应用现状和发展方向;分析了精密锻造设备的特点及应用现状;总结了精密锻造模具的特点,介绍了模具弹性补偿、高速切削、模具补焊等先进的模具设计、制造技术;从数值模拟和反向模拟两个方面综述了成形过程模拟技术在精密锻造工艺中的应用情况及存在的问题;介绍了精密锻造工艺优化技术的研究现状.最后对精密锻造成形技术发展方向进行了展望.     

铝合金圆柱直齿齿轮精锻成形试验研究

为优化圆柱直齿齿轮的精锻工艺,用挤压成形工艺、浮动凹模及分流原理挤压成形圆柱直齿齿轮零件,并比较成形零件齿形的饱满程度,对实现圆柱直齿齿轮的精密模锻生产有一定的指导作用。     

精密锻造成形技术在我国的应用情况及发展趋势（1）

精密锻造成形技术是应用范围越来越广泛的一种先进制造技术。本文简要介绍了精密锻造成形技术的发展概况,列举了大量的工程应用实例来阐明冷锻成形、温锻成形、闭塞锻造成形、铝合金的精密锻造成形、精密热模锻成形、复合成形、等温锻造成形等精密锻造成形工艺在我国的应用情况。在给出了我国精密锻造成形技术目前发展中存在的主要问题的基础上,指出了精密锻造成形技术的发展趋势。     

钛合金HIP近净成形技术在航天上的应用

介绍了钛合金热等静压(HIP)近净成形的工艺特点及其在国内外航天领域的应用情况.与锻造、精密铸造、机械加工等传统成形方法相比,HIP近净成形钛合金综合力学性能高,节约原材料、成形周期短.由于产品的综合力学性能高、尺寸精度可控性好,HIP近净成形技术非常适合异型结构件特别是含空间曲面结构件的精密成形.     

民用飞机大型模锻件的生产及其展望

本文通过对波音飞机钛锻件模锻工艺的研究和生产实践,以锻造实例说明大型钛锻件的模锻技术特点;介绍红原锻铸厂的近期技术改造和对未来发展的展望。     

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.     

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.……     

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...     

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.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

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.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from