低合金高强焊丝退火工艺研究

研究了一种铁基合金焊丝从铸态到焊丝最终成型的制备过程。分析了焊丝制备工艺以及制备过程中合金的组织和性能。采用各种不同温度对材料进行热处理,寻求最佳的处理方案,以降低材料的硬度,并初步探求材料在不同温度参数下去应力软化处理的效果。合金钢丝经1020℃×15min去应力软化处理（空冷）后,硬度由29．8HRC降至21．1HRC,满足了后续拉拔工艺的要求。     

焊丝用盘条拉拔断裂分析

ER70S-6焊丝用盘条在拉拔过程中发生断丝。取断丝材料进行了低倍、夹杂物和显微组织检验及能谱和化学成分分析。结果表明,导致盘条拉拔断裂的主要原因是盘条表面存在显微裂纹和组织混晶。提出了相应的改进措施。     

船用耐海水腐蚀埋弧自动焊材料的研制

研制了一种耐海水腐蚀的埋弧焊丝,该焊丝配用３５０焊剂进行施焊,焊接接头具有优良的综合力学性能,满足了船体钢的焊接要求,填补了该强度级别耐海水腐蚀船用焊丝的国内空白。本文对该焊丝的成分设计、焊剂筛选及耐海水腐蚀性能试验等有关情况进行了介绍。     

纳米改性涂层及焊接工艺参数对无镀铜实心焊丝导电嘴磨损影响的研究进展

环保型无镀铜实心焊丝是气保护实心焊丝发展的主要趋势,而导电嘴磨损是其应用的瓶颈,综述了无镀铜实心焊丝表面纳米改性涂层及焊接工艺参数对导电嘴磨损的影响,认为:纳米颗粒在无镀铜实心焊丝与导电嘴的摩擦界面形成摩擦反应膜可以减少导电嘴的磨损;纳米改性涂层可使焊丝表面的油膜具有优异的润滑、导电、导热三重特性,是减少导电嘴磨损的可行途径;导电嘴的磨损随焊接电流的升高而增大,直流反接(Direct-current Electrode Positive,DCEP)时导电嘴的磨损比直流正接(Direct-current Electrode Negative,DCEN)时严重;电弧烧蚀和电流腐蚀是导电嘴磨损的主要机制。     

圆形超细金属／合金丝研究进展及其在Z箍缩研究中的应用

介绍了圆形超细金属／合金丝制备技术基本原理、技术特点及基本性能，主要包括拉拔技术、电解腐蚀技术及熔融快速凝固技术。回顾了超细W、Mo、Al丝等在Z箍缩丝阵负载材料中的应用。     

钛合金窄间隙激光填丝焊接工艺及接头组织性能分析

采用自主研发的Ti-Al-V-Mo系钛合金药芯焊丝为填充金属,进行TC4钛合金板窄间隙激光填丝焊接工艺实验,研究激光功率、摆动参数、焊接速度和送丝速度等工艺参数对焊缝成形的影响规律;借助高速摄像系统研究焊接过程羽辉及等离子体特性,并对获得的焊接接头组织性能进行分析。研究结果表明：采用激光功率4.0 kW、圆形摆动模式、摆动频率100 Hz、摆幅2 mm、焊接速度0.42 m/min、送丝速度0.6 m/min的工艺参数组合下得到的焊缝成形良好,无明显外观缺陷;当焊丝末端与液态熔池接触距离为0 mm时,过渡方式为液桥过渡,可以实现焊丝熔化金属向熔池的稳定、有序过渡;该焊接工艺获得的20 mm厚TC4钛合金板窄间隙激光填丝焊接头组织性能良好。     

焊丝先镀铜后拉工艺

研究了二氧化碳碳气体保护焊丝电镀铜先镀后拉工艺流程及最佳工艺参数，并对焊丝镀铜质量的影响因素，镀铜生产线的设计等进行了详细的论述。此工艺在国内具有领先地位，产品具有防锈期长，镀层结合力好，送丝性能好等特点，已在江苏，陕西，河南等厂家推广应用，效果甚佳。     

脉冲磁体用高强高导Cu-Nb复合线材的研究进展

高强高导铜合金材料是集优良物理性能和力学性能于一体的有色金属材料，能够同时具备高强度、高电导率以及高热导率等性能。近年来，铜合金材料备受关注，在脉冲强磁场、转换开关、电接触器、引线框架及电车和电力火车导线等诸多领域展现出广阔的应用前景。Cu-Nb复合线材作为一种典型的高强度、高电导、高导热铜基复合材料，是制备超高场脉冲磁体的首选导体材料。本文系统总结了脉冲强磁场发展史，脉冲磁体导体材料用Cu-Nb复合线材的主要制备技术，芯丝结构演变特征，材料的热稳定性、强化机理及导电机理等方面的研究进展，最后指出了目前我国脉冲强磁场突破110 T所需Cu-Nb复合线材存在的问题及面临的挑战，并提出了关于未来研究重点的建议。     

新型燃料电池电解质材料的制备及研究

采用溶胶-凝胶法制备燃料电池电解质材料，用Zahner Elektrik IM6e型电化学工作站对所制备的材料进行质子传导性能测试。探讨了原料配比对凝胶时间及质子传导性能的影响。用x射线衍射、DSC-TGA、MAS-NMR等对所制备的电解质材料进行了表征，探讨了其在中温、低湿条件下保持高传导性能的机理。     

右旋组分对左旋聚乳酸单丝体外降解性能的影响

将质量分数5%的右旋丙交酯(D-LA)组分加入到左旋聚乳酸(PLLA)的制备中得到共聚物PLD955材料并将其制备成单丝。通过60℃加速降解和37℃实时降解试验,利用凝胶渗透色谱、差示扫描量热分析、X射线衍射及拉伸试验等分析测试方法,系统地研究了PLD955单丝和PLLA单丝在2种降解条件下的质量变化、相对分子质量变化、热性能、结晶性能及力学性能的变化。结果表明,实时降解32周,PLLA单丝性能变化不大,而PLD955单丝质量以每周0.63%的速率损失,PLD955单丝重均分子量的半衰期比PLLA单丝快10倍,在该温度降解7周,PLD955单丝的力学强度已损失殆尽。而加速降解条件下,PLLA单丝的断裂强度的半衰期是PLD955单丝的10倍。证明5%D-LA的加入显著加速了PLLA的降解。     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...