EDT的研制及其摩擦学性能

制备了一种含有混合酸多元醇酯润滑油添加剂EDT;用四球摩擦磨损试验机考察了其在N46基础油中的承载能力和抗磨减摩性能,并与常用添加剂ZDDP进行摩擦学性能对比.结果表明:添加剂EDT能显著地提高N46基础油的承载能力,其PB值达1176N,是N46基础油的2倍,比ZDDP的提高了33.3%;同时EDT有优异的抗磨减摩性能,在载荷为392N及490N时,其磨斑直径较ZDDP的分别减小了14.9%和27.3%,其摩擦系数比ZDDP的分别降低了19.7%和34.5%.     

油酸修饰自修复添加剂在金属摩擦副表面成膜过程研究

采用油酸对蛇纹石粉体进行表面修饰,使用红外光谱仪(IR)和X射线衍射仪(XRD)分析了它对粉体的分散机理.使用MM200摩擦磨损试验机研究金属摩擦副在含有自修复添加剂的润滑油润滑下的成膜过程,借助SEM及EDAX测试分析自修复膜层的表面形貌及表面成分组成.结果表明,油酸可以很好的使粉体分散于润滑油中,其作用机理为油酸与粉体表面的羟基发生酯化反应.当摩擦磨损时间很短时摩擦副表面就可出现自修复膜层,但成膜过程和磨损过程同步进行,随着时间的增加,膜层的形成愈来愈稳定,直至覆盖整个金属磨损表面.其成膜机理为,在摩擦过程中,两接触表面上的微凸体对粉体的研磨作用使粉体粒子表面带有大量的悬挂键,同时接触的金属摩擦副也形成活化表面,从而使粉体颗粒吸附在金属表面.在载荷的作用下,粉体颗粒在磨损表面铺展形成自修复膜.     

层状硅酸盐润滑材料对铁基摩擦副的自修复效应

采用机械球磨法制备了一种层状硅酸盐润滑材料,利用往复摩擦磨损试验机评价了其作为润滑油添加剂对45钢摩擦副的自修复效应,借助扫描电子显微镜（SEM）、能量色散谱仪（EDS）及纳米硬度仪（Nano-hardness indenter）对自修复层进行了表征,探讨了其减摩抗磨及自修复机理。结果表明,层状硅酸盐微粉作为润滑油添加剂具有良好的减摩抗磨及自修复性能,尤其在50N、1.0m/s时,其摩擦因数及质量磨损率分别较基础油降低约49.6%和83.8%。添加剂与摩擦表面发生了复杂的理化作用,诱发形成了较为连续的＂多孔＂氧化膜自修复层,厚度约为1.08μm;表面较为光滑平整,主要由Fe、C、O及微量的Mg、Si等元素构成,具有较高的硬度,有效地降低了摩擦磨损。     

磨损表面在线自修复研究

磨损是导致机械零部件失效的主要原因,如何在线修复摩擦表面早期出现的磨损,延长机械设备的工作寿命是当前研究的热点.以锌超细粉体作修复剂,利用摩擦磨损试验机对已磨损金属表面进行了在线自修复试验,并对修复表面的形貌、成分、微观硬度等进行了分析测试.结果表明:所制备的修复剂对磨损表面具有明显的修复作用,形成了修复层.由于金属摩擦副的材质和工作条件的不同,对修复剂、在线自修复工艺等也有不同的要求.提出了油润滑下金属摩擦副磨损表面在线自修复的系统设计.     

纳米坡缕石润滑油添加剂对灰铸铁HT200摩擦磨损性能的影响

制备坡缕石纳米粒子添加到150N基础油的润滑油体系,在MMU-10G摩擦磨损试验机上分别对该纳米粒子润滑油体系和纯150N基础油,在混合润滑条件下的铸铁HT200试样对摩时的摩擦磨损性能进行研究,并用SEM和金相显微镜对磨损表面进行观察和分析,借助EDX测定试样表面成分的变化,探讨摩擦磨损性能变化的机理。结果表明:自制备的用KH550硅烷偶联剂球磨修饰的坡缕石纳米粒子在基础油中分散性良好,在该润滑剂润滑条件下对摩的试样表面生成了自修复膜层,其磨损量明显减小,失重量下降约25.2%,平均摩擦系数下降约32.3%。     

纳米坡缕石润滑油添加剂对45~#钢摩擦副的抗磨及自修复性能

制备的纳米坡缕石粒子经KH550表面修饰后分别按质量分数为2%,4%添加到150N基础油中,采用MMU-10G摩擦磨损试验机考察其作为润滑油添加剂对45#调质钢摩擦副的抗磨减摩和自修复性能。利用电子天平测定试样的失重量以表征其耐磨性能和自修复效果,用光学显微镜和SEM对摩擦表面形貌进行观察和分析,借助EDX测定摩擦表面成分的变化。结果表明:试样在纳米坡缕石添加剂为2%的润滑油体系中自修复作用微弱,磨损率下降有限,减磨仅发生在初期磨合阶段;而试样在坡缕石添加剂为4%的润滑油体系中总磨损量比纯基础油体系下降了26.5%,经成分和形貌分析,该试样表面生成了含坡缕石特征元素呈斑状分布的自修复膜层,耐磨性和自修复效果最好。     

Si3N4陶瓷-冷激铸铁在微量润滑条件下的摩擦学特性

利用MG-200型高速高温摩擦磨损试验机,采用块-盘式实验方法,对Si3N4陶瓷-冷激铸铁摩擦副从室温到150℃进行了微量润滑摩擦磨损实验,得到了该摩擦副的摩擦系数和Si3N4陶瓷的磨损率.同时根据试件的SEM照片和能谱成分分析了摩擦磨损机理,并与无润滑时所得实验结果进行了比较.结果表明:微量润滑条件下Si3N4陶瓷的磨损率和摩擦系数要比无润滑条件下小的多;Si3N4陶瓷的磨损率随载荷和温度的增大而增大,滑动速度的影响要小于载荷的影响;该摩擦副的摩擦系数随环境温度的提高而增大,随速度的增大而减小,载荷的变化对其影响不大;Si3N4陶瓷的磨损是化学磨损、机体物质脱落和磨粒磨损共同作用的结果,其中化学磨损是引起其他两类磨损的主要原因.     

类金刚石薄膜在干摩擦、油和脂润滑条件下的摩擦学性能分析

通过钢/类金刚石(DLC)薄膜摩擦副在干摩擦4、122油和L252脂润滑条件下的球-盘摩擦学试验,对比分析润滑条件、载荷、速度对DLC膜摩擦系数的影响,利用原子力显微镜分析膜层磨损性能,研究润滑条件对膜层磨损寿命的影响。结果表明:油、脂润滑下DLC膜最大静摩擦系数分别减小了17%和38%;从0～2000 r/min转速范围内,DLC膜摩擦系数随转速增加而减小,油润滑下相比干摩擦DLC膜摩擦系数小15%～48%,脂润滑下相比干摩擦DLC膜摩擦系数在0～500 r/min转速范围小,超过500 r/min后干摩擦DLC膜摩擦系数小;油和脂润滑条件下,DLC膜层的磨损程度明显降低,磨损率相比干摩擦条件下分别减小了7.4倍和15.5倍。     

在点线接触条件下钢/钢摩擦副的干摩擦高温减摩抗磨性能的研究

用多功能SRV实验机评价了钢/钢摩擦副在干摩擦条件下的的高温减摩抗磨性能,并对高温磨损机理进行了探讨.结果表明,钢/钢摩擦副的高温摩擦系数随着实验负荷的增加呈下降趋势,而随着实验时间的延长呈增长趋势.钢/钢摩擦副的线接触高温摩擦系数明显比点接触时的高温摩擦系数大,SPHC/GCr15摩擦副的高温摩擦系数明显高于GCr15/GCr15摩擦副的高温摩擦系数.钢球在点接触条件下的磨损随实验负荷的增加呈线性增长趋势,而钢柱在线接触条件下的磨损随实验负荷的增加呈线性降低趋势.在相同负荷下,SPHC/GCr15摩擦副的磨损要较GCr15/GCr15摩擦副的磨损略微大.钢/钢摩擦副在高速度下的磨损机理主要是磨粒磨损,而在较低速度下主要是磨粒磨损和粘着磨损.     

机械油中添加剂对铜-钢摩擦副的磨损自补偿效应

运用改装的四球试验机考察了ZSC添加剂在N68油中对铜-钢摩擦副的磨损自补偿效应，研究表明：ZSC添加剂具有优异的减摩和节能效应，对铜-钢摩擦副及其配件产生了优异的自补偿耐磨效应，零磨损效应和自修复效应。     

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.……     

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.……     

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 ...     

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     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.