锻造变形量对FeNi基奥氏体合金力学性能的影响

研究了最后一火锻造变形量对FeNi基合金微观组织和性能的影响.结果表明,变形量为10%时合金中出现孪晶,其数量随着变形量的增大而增多.随着最后一火锻造变形量的增大,室温拉伸强度因晶粒细化而提高;但是,变形量大于15%后,室温塑性因孪晶对晶内滑移的阻碍作用和晶界碳化物对晶界结合力的削弱而降低;变形量大于10%时高温强度和塑性下降,其原因是孪晶与晶界相交阻碍了晶界滑动,相交部分在外力作用下易产生应力集中导致裂纹萌生并沿晶界扩展.     

GH2132屈服强度不合格分析与研究

GH2132合金适于做航空发动机承力部件。本文分别从原材料、热处理、锻造变形量、显微组织几个因素分析了GH2132合金屈服强度不合格的原因。研究结果表明，合金屈服强度不合格可能与取样位置和锻造变形量有关，原材料和晶粒度对屈服强度性能影响不大，而热处理可能提高个别试样的屈服强度。     

GH6159合金成分−组织−性能关联研究

目的 研究不同成分GH6159合金冷拉态和热处理态显微组织的变化情况,分析不同成分对合金室温和高温拉伸性能的影响规律,为GH6159合金成分优化与性能提升提供理论指导。方法 基于MP159合金成分,设计熔炼了4种不同成分的GH6159合金,经锻造开坯和热轧,进行了拉伸率为48%的冷拉变形和663 ℃/4 h的时效热处理,分别制成冷拉态和热处理态GH6159棒材,采用MTS 8810拉伸实验机进行室温和595 ℃的高温拉伸测试,获得了不同成分合金冷拉态和热处理态的室温和595 ℃高温拉伸性能,结合OLYMPUS−PM3光学显微镜和Tescan Mira 3 XMU扫描电子显微镜观察了显微组织的变化情况。结果 GH6159冷拉态棒材内存在大量的变形孪晶,热处理态组织内析出了弥散分布的强化相,合金拉伸性能主要受到基体元素和强化相元素的影响。结论 较高含量的Co、Cr、Ni基体元素有利于提高冷拉态GH6159合金的室温和高温拉伸强度,而Al、Ti、Nb强化相元素会提高热处理态GH6159合金的室温拉伸强度,但过高的Ti元素会降低合金强度,一定含量的Al、Ti、Nb元素有利于提高冷拉态和热处理态合金的高温塑性。     

中间形变热处理对2A97铝锂合金组织和性能的影响

通过室温拉伸、晶间腐蚀、电子背散射衍射(EBSD)、透射电镜(TEM)等测试方法,对中间形变热处理过程中进行不同压缩变形量处理的2 A97铝锂合金厚板短横向室温拉伸性能、晶间腐蚀性能和合金的宏微观组织进行了系统研究.结果表明,随压缩变形量的增加,合金再结晶程度提高,强度和伸长率先增加后降低.压缩变形量为20％时,再结晶晶粒细小,晶粒内包含均匀弥散分布的δ'相,晶界处的δ'相断续分布,合金的拉伸性能最好,伸长率明显提高;压缩变形量为25％时,合金的耐晶间腐蚀性能最好.合金的拉伸性能和腐蚀性能是由晶粒形貌和析出相的数量及分布共同作用的结果.     

磷对GH761合金固溶水淬组织屈服强度的影响

通过固溶水淬处理抑制γ'相析出,获得单一γ相组织,研究了磷对GH761合金基体γ相的强化作用及其机制.结果表明,磷对合金的晶粒组织没有显著影响,但是使GH761合金基体γ相的室温和650℃拉伸屈服强度和室温硬度提高.磷对基体变形过程中的位错运动具有明显的影响,低磷含量时滑移线平直;磷含量升高使滑移线弯曲并互相缠结.磷提高合金基体的强度,阻碍晶粒变形,是其降低合金蠕变速率的重要原因.     

V元素对铁镍基变形高温合金GH4061组织和性能的影响

采用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和电化学萃取相分析等手段,研究了V元素对GH4061合金晶粒度、碳化物和γ?/γ"强化相等影响,测试了不同V含量试样的室温和750℃拉伸性能以及750℃/460 MPa持久性能,分析了V元素对合金显微组织和力学性能的影响。结果表明：GH4061合金中添加V元素促进了MC型碳化物和γ?/γ"相析出,使晶粒尺寸小幅减小;V元素通过增大γ基体的晶格常数,降低γ基体与γ?相的错配度,抑制了γ?/γ"相在750℃的快速粗化;V元素添加对室温拉伸性能影响不大,但可显著提升750℃拉伸强度和持久寿命;当V含量为0.4%(质量分数)时,GH4061合金具有最佳的750℃持久性能。     

燃气轮机隔热板GH22合金的组织和力学性能

采用真空感应熔炼的方法制备GH22母合金,然后真空感应重熔浇注成等轴晶成形试棒,测试其室温拉伸、高温拉伸和持久性能.利用熔模失蜡精密铸造技术生产了重型燃机GH22隔热板铸件,对隔热板不同部位进行了宏观晶粒度、光学金相、扫描电镜及能谱分析.从国产、进口隔热板底板分别取样加工成力学性能试样,进行了室温拉伸、高温拉伸和高温持久性能测试.结果表明:国产GH22母合金的成分和性能满足要求.国产铸件取样试样的宏观晶粒度、室温拉伸、高温拉伸性能与国外铸件相当.国产铸件具有更高的高温持久强度,这主要是由于国产GH22母合金中碳含量更高,合金组织中在枝晶间和晶界处析出更多的碳化物相.     

冷变形对GH3535合金的组织和力学行为的影响

对GH3535合金进行不同变形量的拉伸,研究了冷变形对GH3535合金力学性能的影响,用OM、TEM对冷变形后的组织结构进行观察并结合真应力-真应变曲线分析了GH3535合金加工硬化的变形机制。结果表明,GH3535合金具有显著的加工硬化特性,冷变形使其强度和硬度提高,但是塑性降低;随着变形量的增大晶粒沿着变形方向伸长,孪晶变多且更粗大。GH3535合金的加工硬化规律遵循Ludwigson模型,随着冷变形量的增大GH3535合金的加工硬化指数降低,变形机制由单滑移和孪生逐渐变成交滑移和孪生。当变形量小于30%时加工硬化主要是位错的长程应力场和孪晶引起的,当变形量大于30%时主要是位错的短程应力场和形变孪晶引起的。     

热处理对GH783合金组织与性能的影响

研究了抗氧化型低膨胀高温合金GH783的热处理制度.结果表明:随着固溶温度的升高,晶粒有所长大,在1140℃固溶晶粒开始不均匀长大;室温拉伸强度有所下降,高温拉伸塑性有所升高,持久塑性在1115℃固溶时最高.随着β时效温度的升高,二次β相明显增多,γ′相也发生比较明显的变化;在845℃进行β时效,合金可以获得良好的组织和综合性能.     

GH93合金长期时效对组织稳定性和性能的影响

本文研究了GH93合金经700℃和800℃长期时效对其组织稳定性和室温、高温拉伸性能及高温持久性能的影响。结果证明,GH93合金经700℃时效后的组织是稳定的。     

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.