耐事故燃料包壳用FeCrAl不锈钢的研究进展

3.11日本福岛核事故后,国内外围绕提高核燃料元件的事故包容能力和固有安全性课题开展了大量的耐事故燃料(ATF)的研发工作,其中性能更先进的包壳材料是ATF研究的前沿和难点。Fe Cr Al合金优良的高温性能结合管材制备工艺的技术成熟度和经济性,促使该合金包壳成为近期ATF包壳研发的首选目标。简介了国外在ATF包壳候选材料的筛选和Fe Cr Al不锈钢上的研究进展,综述了ATF包壳用Fe Cr Al不锈钢高温蒸汽氧化性能、力学性能、中子辐照性能和应力腐蚀性能等方面的研究现状,指出了Fe Cr Al包壳研制和工程应用等方面需突破的关键技术和研究方向,其中成分优化控制及制备工艺、中子辐照性能和应力腐蚀性能等工程应用的评价是未来研究的重点和难点。     

几种典型材料中子辐照损伤模拟计算

基于Lindhard-Robinson模型，利用NPRIM和NJOY程序，模拟计算了4种典型辐照场景下，Ti、Ni、Fe、Cr和316L等常用材料的中子辐照损伤参数。计算结果表明，DPA产生速率和He产生速率与辐照场景的中子能谱关系紧密，Fe是比较好的耐中子辐照材料。     

多因素耦合下Cr35Ni45Nb钢乙烯裂解炉管损伤数值模拟

基于连续损伤力学理论,利用FORTRAN语言开发了多因素耦合下材料损伤发展的ABAQUS用户子程序,模拟了1050℃温度下,蠕变-渗碳耦合作用的Cr35Ni45Nb钢损伤发展过程。结果表明:承受单一蠕变损伤的炉管外壁最先失效,而承受蠕变-渗碳耦合作用下的炉管内壁最先开裂。单一蠕变因素下Cr35Ni45Nb钢的内壁Von-mises应力和最大主应力随着服役时间的延长出现先降低后增长的趋势。外壁的Von-mises值和最大主应力随着服役时间的延长而增大,从而导致炉管外壁的损伤发展速率高于内壁。蠕变-渗碳耦合作用下Cr35Ni45Nb钢的内壁Von-mises应力和最大主应力随着服役时间的延长而降低,而外壁则相反。     

Ni-Fe-Cr合金共沉积的电化学行为

用线性扫描、循环伏安、交流阻抗法研究了柠檬酸体系中Ni、Fe、Cr以及Ni-Fe-Cr合金共沉积的电化学行为,分析了温度、光亮剂和柠檬酸对Ni-Fe-Cr合金共沉积的影响.结果表明:Ni-Fe-Cr共沉积的速度比Fe、Cr沉积的速度快,比Ni沉积的速度慢,Fe为异常沉积;在峰电位-1.38 V时获得的镀层组成为57.5?,38.2%M,4.3%Cr;随温度升高,阴极极化减小,Ni-Fe-Cr镀层中Cr含量下降,适宜的沉积温度为20～40℃;光亮剂使阴极极化增大,但使镀层耐蚀性下降;柠檬酸有增大电流密度、促进Ni-Fe-Cr共沉积的作用;Ni-Fe-Cr合金的共沉积为电化学控制过程;Ni-Fe-Cr三元合金比Ni-Fe二元舍金难以电沉积,但镀层的耐蚀性更好.     

精密合金锻裂的金相分析

精密合金是指具有特殊物理性能的合金材料。包括软磁、永磁、温度补偿、弹性、膨胀,热双金属,精密电阻、及其它贵金属材料。这类合金在成分上最大的特点是Ni、Cr等合金元素的含量很高,不少还脱离了铁基的范畴。由于这类材料在不同温度下的组织、成分和各种性能往往与一般钢材     

事故容错燃料包壳候选材料的研究现状及展望

2011年福岛核电站事故中,反应堆堆芯燃料中的锆合金包壳在事故工况下与高温水蒸汽发生剧烈氧化反应继而产生大量的氢气和热量,最终导致反应堆堆芯熔化和氢气爆炸,对社会和环境造成极大负面影响。自此之后,国内外纷纷展开对事故容错燃料的研究开发。相较于传统的UO2-Zr合金燃料体系,事故容错燃料能够在反应堆正常运行工况下维持或提高燃料性能,并在事故发生后相当长的一段时间内维持堆芯完整性,提供足够的时间裕量来采取事故应对措施。反应堆堆芯环境非常极端,包壳长期处于高温高压腐蚀介质中,同时还受到中子辐照的影响,因此新型包壳材料需要较好的耐腐蚀性和辐照稳定性。经不同研究者的研究评估,目前能够替代Zr合金的事故容错燃料包壳材料可分为陶瓷材料和金属材料两类:陶瓷材料主要以SiC/SiC复合材料为代表;金属材料主要有以FeCrAl为代表的Fe基合金和以Mo为代表的难熔金属及其合金。上述三种替代Zr包壳的材料各有其利弊,均未达到工程应用水平,并且都存在待解决的关键性问题。其中,FeCrAl合金的研发进展最快,目前在热学性能、力学性能、抗腐蚀性能、抗辐照性能等方面表现较好,但在工业加工和焊接等方面仍有待进一步改善。就SiC/SiC复合材料而言,由于SiC自身的高脆性而导致力学强度不足,不同的研究者提出了不同的结构设计思路试图降低包壳管失效概率,但包壳最终的结构设计仍未确定,而辐照引起的热导率急剧降低及连接密封和加工制造等方面还在不断研究中。Mo及Mo合金的力学性能和抗辐照性能较好,但自身抗腐蚀性较差,解决思路主要集中在提高钼纯度、调整合金的元素成分、进行表面涂层等方面。目前,对后两种材料包壳管的加工能力均未达到薄壁长管的工业制造水平。对于这几种候选包壳材料,需要建立属性数据库和一套完善的标准来衡量材料的质量。此外,还需开发相应的程序来评估包壳在堆内的行为。本文主要综述了SiC/SiC复合材料、FeCrAl合金、Mo及Mo合金三种候选包壳材料的研究进展,包括候选包壳材料的物理性质、耐腐蚀性能、力学性能、抗辐照性能、芯块-包壳力学与化学相互作用、在事故工况下的行为和工程应用等,综合分析了事故容错燃料包壳材料当前的研究现状,指出了各事故容错燃料包壳未来需集中解决的关键性问题。     

CrFeCoNiCu多主元高熵合金的相分析

利用高分辨SEM与TEM观察显微组织,同时结合相图分析,提出了CrFeCoNiCu多主元高熵合金相的鉴定方法,结果表明:微观组织为枝晶和枝晶间组织,枝晶间存在大量纳米析出相。主要组成相包括枝晶内的Fe,Cr,Ni,Co的FCC固溶体相,枝晶间非晶相和Cu,Ni的FCC固溶体相。相图分析表明,合金材料在1400℃和1100℃左右发生的两次相变,形成了CrFeCoNiCu高熵合金的组织结构。     

均匀热流作用下含裂纹板I 型温度应力强度因子的解析解

研究一种新的温度边值问题。含中心裂纹无限大板受远场均匀热流作用,热流密度方向与裂纹有一夹角。当裂纹面上维持一恒定温差时,采用复变函数理论,得出了温度场、温度应力场与位移场的解析解。利用位移单值条件,确定出温度应力强度因子的解析表达式。针对铝合金LY12 材料进行了相应数值计算,分析了热流密度大小与方向对温度分布与温度应力强度因子的影响。研究表明:该文给定的温度边界条件下,只产生Ⅰ 型温度应力强度因子,不产生Ⅱ 型温度应力强度因子。温度应力场取决于热流密度沿裂纹方向的分量,垂直于裂纹方向的分量对温度应力场没有影响。     

锆材在核电站的应用及前景

锆合金因其优良的核性能和适宜的机械性能,在核电反应堆中作为包壳材料和结构材料得到了广泛应用.介绍了锆合金包壳管材在核电站中所起的重要作用,具体用途、用量,以及我国锆合金材料的研制和生产现状.指出随着我国核电事业的发展,对锆合金材料的需求仅更换的包壳管到2010年将达到120t,我国应加速核电用锆合金材料的国产化进程,这样才能自主地发展我国的核电事业.     

多元合金团簇构型优化的研究

为了研究多元合金基体的稳定性,探讨了获得多元合金团簇平衡几何构型的途径,根据随机行走思想编写了多元合金构型优化的计算程序,并铸造了3种合金样品,其基体成分分别为Fe7Cr0.68Mn2.0V1.47Ni1.37Si0.7C,Fe8Cr0.74Mn2.3V1.45Ni1.55Si0.5C,Fe7Cr0.80Mn1.86V1.47Ni1.47Si0.8C,研究了这3种Fe基多元合金奥氏体基体的稳定性及平衡几何构型.计算结果表明:合金1的奥氏体基体最稳定,合金3的奥氏体基体最不稳定,最容易转变成马氏体,与X射线衍射结果一致.     

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