调质工艺对X80级管件钢性能与组织影响研究

为研究调质工艺对X80级管件钢的性能和组织影响,通过力学性能检验、光学显微镜(OM)、透射电镜(TEM)、萃取复型及电子背散射衍射(EBSD)等手段,研究了同一温度淬火后,不同回火温度对X80级管件钢性能和组织的影响.结果表明,经940℃淬火后,在500~650℃范围内回火,试验钢的屈服强度和抗拉强度随回火温度的升高均先增加后降低.随回火温度的升高,试验钢由板条贝氏体铁素体(BF)和粒状贝氏体(GB)的混合组织转变为GB和准多边铁素体(QF)混合组织,M/A岛由细长条状变为颗粒状,并发生分解,BF中的板条亚结构逐渐弱化.在500~600℃范围内,组织中析出相随回火温度升高逐渐增多,600℃时析出相开始聚集长大,温度继续升高,析出相尺寸明显增大.回火过程中,试验钢屈服强度受基体组织软化和析出强化两方面的影响.试验钢的低温冲击韧性随回火温度升高逐渐增大,主要是大角度晶界比例增加所致.     

冷却速度对低合金高强油罐用钢组织和硬度的影响

以含0.012Ti大型石油储罐用钢为研究对象,分析了不同冷却速度对石油储罐用钢显微组织和硬度的影响,结果表明在不同的冷却条件下,室温下得到的组织比较复杂,包含了多边形铁素体PF、珠光体P、退化珠光体PD、魏氏铁素体WF、块状铁素体BF、针状铁素体AF,粒状贝氏体GB、板条贝氏体LB、马氏体M及残余奥氏体等,相应的随着冷速的提高,硬度值明显增大。     

航空齿轮钢16Cr3NiWMoVNbE的真空低压渗碳

对航空齿轮钢16Cr3NiWMoVNbE进行真空低压渗碳热处理,研究了真空渗碳、淬火、冰冷处理以及回火工艺对材料的组织和性能的影响。结果表明：实验钢经渗碳淬火处理后,从表面到心部的组织可分为碳化物区、碳化物与针状马氏体混合区、针状马氏体区和心部板条马氏体区。在碳化物区的晶界有大量的块状Cr碳化物析出,在析出位置Ni元素较少。在针状马氏体和板条马氏体基体中细小的析出物为Nb、V、Mo微合金元素的碳化物。从渗碳钢表面到心部,随着碳浓度的降低硬度曲线呈现先升高后降低的趋势,渗层深度为0.95 mm。冰冷处理使残余奥氏体进一步转化为马氏体,使实验钢的硬度大幅度提高。     

钛微合金化热轧TRIP钢的连续冷却相变研究

用Formastor-FII相变仪研究了钛微合金化TRIP在不同开冷温度下的连续冷却相变,建立了实验钢的连续冷却转变曲线,分析了铁素体、贝氏体及马氏体的相变规律.结果表明,随着冷却速率的增加,实验钢依次经过铁素体、贝氏体及马氏体相区,在较宽的冷却速率范围内,均可获得贝氏体及马氏体组织,其Ms点为450℃左右;随着开冷温度的降低或冷却速率的提高,实验钢的铁素体及贝氏体开始转变温度降低,抑制了铁素体及贝氏体相变;随着冷却速率的增加,实验钢的显微组织由铁素体+粒状贝氏体逐步转变为板条贝氏体+板条马氏体及板条马氏体组织;当冷却速率较低时,铁素体由晶内铁素体和晶界铁素体组成,晶内铁素体形核质点为复杂的氧化物及硫化物.     

焊后热处理对T92钢焊接接头组织及性能的影响

通过模拟现场热处理工艺,研究了T92钢焊接接头在不同回火温度下的组织和性能。结果表明,焊缝硬度和母材抗拉强度均随回火温度的升高而降低。接头处未回火的马氏体粗大,呈细针状;740-780℃回火,马氏体组织变细,板条特征明显;超过780℃,马氏体板条特征消失,表现为屈氏体组织;随回火温度升高,母材碳化物产生偏聚,铁素体含量增加;780℃以下回火母材力学性能满足ASME标准要求。     

各种原始组织对亚温淬火强韧性的影响

本文研究了原始组织为马氏体、上贝氏体、下贝氏体和正火态组织的30CrMnSi 钢经亚温淬火后的强韧性。试验结果表明,具有马氏体和贝氏体原始组织的钢,经亚温淬火后的强韧性均优于正火态钢。钢的强化效应是与两相的相对量和组织形态有关.亚温淬火能明显抑制高温回火脆性。     

新型贝氏体钢的组织和冲击疲劳性能研究

通过显微组织观察和冲击疲劳实验,研究了不同热处理新型贝氏体钢的组织和冲击疲劳性能.结果表明:新型贝氏体钢正火低温回火的组织由贝氏体铁素体和奥氏体组成,淬火低温回火组织为回火马氏体和残余奥氏体,正火低温回火热处理的冲击疲劳寿命高于淬火低温回火热处理的冲击疲劳寿命.分析了多冲疲劳裂纹扩展的行为,讨论了正火低温回火提高冲击疲劳的原因.     

用示波冲击法测定42CrMo钢的冲击韧性

用示波冲击法测定了在冲击载荷下,淬回火态42CrMo钢的载荷-挠度曲线,并将冲击总功分成裂纹萌生功和裂纹扩展功;研究了回火温度对42CrMo钢回火组织与冲击韧性的影响。结果表明42CrMo钢在回火过程中,随回火温度升高,弹性功基本不变,裂纹萌生功略有升高,而裂纹扩展功迅速增加,42CrMo钢对缺口敏感,随回火温度升高,缺口敏感性降低,淬火态42CrMo钢经500—590℃回火,其组织由板条马氏体和条状及粒状θ-Fe_3C组成;冲击断口为准解理与韧窝混合断裂,随回火温度升高,韧窝增多,准解理减少。     

塑料模具标准件顶杆用65MnV钢的组织分析

对新型塑料模具标准件顶杆用钢６５ＭｎＶ在淬火和氏温回火过程组织的变化进行了系统的研究。结果表明,６５ＭｎＶ钢的低温淬火组织为位错马氏体组织,随淬火温度的升高,淬火组织逐渐由针状与板条状马氏体的混合组织变成针状马氏体组织,马氏体组织的亚结构由位错型马氏体向孪晶马多体转变。钢在低温回火时析出与基体共格的弥散分布的须状ε碳化物,ε碳化物随回火温度的升高而发生转变,形成非共格的棒状渗碳体组织。     

直接淬火低碳贝氏体钢的回火组织与力学性能

利用SEM,TEM等实验方法,研究了不同回火温度对直接淬火Fe-Mn-Mo-Nb-Ti系低碳贝氏体组织和力学性能的影响.结果表明,580℃回火后钢板具有最佳综合力学性能,抗拉强度805MPa,屈服强度719MPa,延伸率25.8%,-20℃冲击功106J.随回火温度的升高,板条贝氏体回复作用逐渐加强,位错通过运动、合并...     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to