Citisteel 4060mm 宽厚板轧机板形问题的分析和改进措施

通过对 Citisteel三年板凸度数据的分析 ,认为采用合理的配辊制度和精心操作可提高板形质量 ,通过增加轧辊原始凸度可降低平均板凸度 ,但不能改进板凸度的标准差 ,因此生产出来的钢板凸度波动较大。分析后认为采用动态设定板形测控方法的板形最佳规程 ,不但可以进一步降低平均板凸度 ,而且可以大大降低其标准差。通过与中国首钢和舞钢两套宽厚板轧机对比及参考它们的经验 ,Citisteel工作辊换辊周期应当减小 ,轧 4 0 0 0 t左右换一次工作辊比较合适。文中提出用动态设定型板凸度模型建立轧辊热凸度模型的新方法     

4100mm宽厚板轧机支承辊辊型曲线优化仿真分析

 辊间接触压力分布是影响宽厚板板形质量和轧辊使用寿命的重要因素,为了获得均匀的辊间压力分布,以4100mm宽厚板四辊轧机为对象,考虑轧件弹塑性变形和辊系弹性变形耦合作用,采用弹塑性热-力耦合非线性有限元方法,数值模拟分析了宽厚板轧制过程的辊间接触压力分布规律,并通过仿真分析,对支承辊辊型及其边部卸载曲线进行了选型和优化改进,获得了以二次曲线为辊凸度和抛物线为辊肩部卸载曲线的辊形,延长了轧辊的使用寿命,改善了宽厚板的板型质量。     

厚板轧制的平直度控制技术

1　前言近年来 ,为了减少工序 ,用户对厚板平直度及尺寸精度的要求越来越严格。另外 ,以节能、减少工序为目的轧辊额定轧制量规程及提高成品率为目的平直度、板凸度控制技术的开发也越来越得到重视。此前 ,国外某厂厚板轧机上 ,通过优化工作辊原始凸度及轧制规程计算时凸度率的控制 ,已将轧制率的降低控制在最小的限度 ,逐步确立了进行平直度及板凸度的控制技术。然而 ,精确地获得预测平直度、板凸度等控制所需的信息是很困难的。此外 ,模型精度以外轧制负荷预测误差、轧辊热凸度、磨损的预测差等各种因素对平直度、板凸度都会有影响。仅根…     

提高宽厚板轧辊使用寿命的工艺研究

分析了影响宽厚板轧辊使用寿命的因素及产生的原因,从轧辊选材、事故辊使用及磨削、轧制计划编排、配辊工艺以及支承辊倒角优化等方面制定了降低辊耗的对策,轧辊消耗降低了约26%。精轧工作辊毫米轧制量由原来的2 800 t/mm提高到3 200 t/mm,粗轧工作辊的毫米轧制量由原来的12 000 t/mm提高到14 000 t/mm,大幅提高了轧辊的使用寿命。     

宽带钢热连轧机的粗轧辊系配置方案与应用

为解决粗轧轧制稳定性,减少轧辊异常报废损失,设计并应用了变接触支撑辊辊形和负凸度工作辊辊形。该辊系配置使得辊间接触长度与轧制带钢的宽度基本相等,消除了有害接触区,使辊间接触应力均匀化,并提高了 辊缝横向刚度,改善了轧辊的磨损,增强了板坯轧制过程的对中和稳定性。     

现有板带轧机改造的几种途径

随着生产的发展,对板、带轧机的要求日趋严格。希望产量高(如能大压下量轧制,以减少轧制道次;高的板、带材收得率和整机利用率等)、质量好(就其外形而言,纵、横向厚度偏差小和板型良好等)和成本低(如能耗低;所需轧辊储备量少和轧辊寿命长等)。我国现有的板、带轧机,多为普通的四辊轧机。其共性问题是:产量、质量和成本都不能满足生产发展的要求。为了提高板、带材质量,虽然采用过预磨工作辊凸度;调节辊身温度分布以改变轧辊热凸度;     

马钢CSP热轧PFC板形模型的分析与应用

利用有限元分析软件ANSYS对轧机承载辊缝变形的仿真,分析轧机轧制力、弯辊力及工作辊窜辊对承载辊缝的凸度影响程度,结合现场机架间带钢的浪形,优化二级板形模型设定参数,实现轧机稳定轧制。实践证明,人工修正轧机负荷分配以及CVC轧辊位置,可更好地控制前机架比例凸度,满足后机架间平直度目标的要求,从而提高板凸度的命中率及轧机轧制的稳定性。     

梅钢1422热连轧机组凸度控制研究

热带钢凸度是板形的一项重要指标。据此,结合梅钢1 422 mm轧线的实际生产情况,对热轧带钢凸度控制的影响因素进行了分析,并分别从原始辊型配置,轧辊热凸度的控制,机组窜、弯辊的配合应用,轧制计划的编排及现场操作的调整等方面提出了相关见解。     

高精度铜带轧机有载辊缝的调控性能分析

利用非线性有限元软件ABAQUS,将高精度铜带轧机辊系及轧件统一考虑建立有限元模型,分别计算了板宽、轧制力、弯辊力、工作辊凸度变化时高精度铜带轧机轧辊的变形,并得出了上述影响因素变化时对有载辊缝凸度的影响规律,分析了板宽对轧制力影响率、弯辊影响率及工作辊凸度影响率的影响,得出的规律可为高精度铜带轧机的有载辊缝的调控提供科学的依据。     

3450mm宽板轧机配辊及辊形优化

通过实践摸索以及对3450mm四辊可逆式轧机轧辊系统的大量数据进行分析,找到了较为优化的配辊方法及辊形制度,实际使用效果较好．达到了减小板凸度、提高成材率、提高轧辊使用寿命的目的。     

电感耦合等离子体原子发射光谱法测定铍中11种杂质元素

铍中铝、钴、铬、铜、铁、镁、锰、镍、铅、硅和锌等11种杂质元素含量的准确测定,是判定铍材是否合格的重要指标。目前,上述杂质元素的测定标准为GJB 2513A—2008《铍化学分析方法》,方法分别采用光度法和原子吸收光谱法对各元素逐一测定,测定周期很长。试验采用盐酸-硝酸溶解样品,选择Al 308.215nm、Co 230.786nm、Cr 284.325nm、Cu 324.754nm、Fe 261.187nm、Mg 285.213nm、Mn 260.569nm、Ni 221.647nm、Pb 182.205nm、Si 250.690nm、Zn 213.856nm为分析谱线,采用标准加入法(MSA)配制标准溶液系列消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定铝、钴、铬、铜、铁、镁、锰、镍、铅、硅和锌,从而建立了铍中11种元素的测定方法。各待测元素校准曲线的线性相关系数均大于0.9995;各元素的定量限为0.001%~0.002%。实验方法用于测定铍样中铝、钴、铬、铜、铁、镁、锰、镍、铅、硅和锌,结果的相对标准偏差(RSD,n=10)为0.63%~8.6%,回收率为90%~110%。按照实验方法测定铍样中上述11种元素,测定结果与采用GJB 2513A—2008测定的结果吻合。     

Management of Fluid Mud in Estuaries, Bays, and Lakes. II: Measurement, Modeling, and Management

Techniques for measurement, modeling, and management of fluid mud are available, but research is needed to improve them. Fluid mud can be difficult to detect, measure, or sample, which has led to new instruments and new ways of using existing instruments. Multifrequency acoustic fathometers sense neither density nor viscosity and are, therefore, unreliable in measuring fluid mud. Nuclear density probes, towed sleds, seismic, and drop probes equipped with density meters offer the potential for accurate measurements. Numerical modeling of fluid mud requires solving governing equations for flow velocity, density, pressure, salinity, water surface, plus sediment submodels. A number of such models exist in one-, two-, and three-dimensional form, but they rely on empirical relationships that require substantial site-specific validation to observations. Management of fluid mud techniques can be classified as those that accomplish: Source control, formation control, and removal. Nautical depth, a fourth category, defines the channel bottom as a specific fluid mud density or alternative parameter as safe for navigation. Source control includes watershed management measures to keep fine sediment out of waterways and in-water measures such as structures and traps. Formation control methods include streamlined channels and structures plus other measures to reduce flocculation and structures that train currents. Removal methods include the traditional dredging and transport of dredged material plus agitation that contributes to formation control and/or nautical depth. Conditioning of fluid mud by dredging and aerating offers the possibility of improved navigability. Two examples—the Atchafalaya Bar Channel and Savannah Harbor—illustrate the use of measurements and management of fluid mud.     

Review of Alcoholism: A bio-psycho-social approach.

Reviews the book, Alcoholism: A bio-psycho-social approach by Jerome David Levin (1990). This small volume sets its task as providing counseling students with a comprehensive knowledge base "summarizing biochemical, pharmacological, physiological, anthropological, sociological, epidemiological, historical, and psychological findings on alcohol and its use and abuse" (Preface, p. xi). It treats each of these, in varying degrees of depth, in seven chapters. Perhaps the greatest strength of the book is its thorough presentation of the medical consequences of alcoholism, the mechanisms involved, and the interplay between biological and psychological factors. Unfortunately, this volume does not provide sufficient coverage of treatment-related issues. It may serve as an introductory overview of the alcoholism field for undergraduate or graduate students, or professionals from other fields. It is too advanced, however, in its use of concepts and language, for paraprofessional students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

电感耦合等离子体原子发射光谱法测定锰铁合金、锰硅合金和金属锰中8种微量元素

锰铁合金、锰硅合金、金属锰中铅、砷、钛、铜、镍、钙、镁、铝的含量决定了产品质量,以往常采用化学法或原子吸收光谱法进行测定,但存在准确度较差或测定速度不能满足要求等问题。为了实现上述元素的准确、快速测定,建立了采用电感耦合等离子体原子发射光谱法(ICP-AES)测定锰铁合金、锰硅合金和金属锰中微量铅、砷、钛、铜、镍、钙、镁、铝的方法。实验以硝酸、盐酸、氢氟酸、高氯酸分解样品,并使硅与氢氟酸反应生成四氟化硅挥发除去,试液中剩余共存元素主要有铁、锰等。实验结果表明,铁不干扰测定,通过在标准溶液系列中进行锰基体匹配消除锰基体效应的影响。以2mL高氯酸和6mL盐酸混合酸(8%)作为分析介质,可以达到最佳分析效果。在各元素校准曲线线性范围内,线性相关系数在0.9992~0.9999之间;方法中各元素的检出限在0.0001~0.0040μg/mL。实验方法用于测定锰铁合金、锰硅合金、金属锰中铅、砷、钛、铜、镍、钙、镁、铝,结果的相对标准偏差(RSD,n=11)在2.2%~9.4%;回收率在95%~105%;选择7个实验室进行了验证试验,各实验室间结果基本一致;按照实验方法测定了4个标准样品(材字-32、YSB C 28618、YSB C 26605)中铅、砷、钛、铜、镍、钙、镁、铝,结果与认定值相吻合。     

电感耦合等离子体原子发射光谱法测定硅铁钡孕育剂中9种元素

采用硝酸和氢氟酸溶解样品,高氯酸冒烟驱尽硝酸-氢氟酸,盐酸溶解盐类,选择Ba 233.527nm、Fe 259.940nm、Ca 317.933nm、Mn 257.610nm、Cr 267.716nm、Al 394.401nm、Ni 231.604nm、Cu 327.396nm、P 178.284nm为分析线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钡、铁、钙、锰、铬、铝、镍、铜、磷,从而建立了硅铁钡孕育剂中钡、铁、钙、锰、铬、铝、镍、铜、磷等9种元素的测定方法。各元素校准曲线的相关系数均大于0.9995;方法中各元素检出限为0.00006%~0.00069%。按照实验方法测定标准样品GSB03-1607-2003中钡、铁、钙、锰、铬、铝、镍、铜、磷,结果的相对标准偏差(RSD,n=11)为0.63%~3.4%。实验方法用于测定标准样品GSB03-1607-2003和YSB14607-2001中钡、铁、钙、锰、铬、铝、镍、铜、磷,测定值与认定值基本相符。     

Contrasting Clogging in Granular Media Filters, Soils, and Dead-End Membranes

Clogging in porous media is a problem in environmental engineering, hydrogeology, soil science, and petrology. However, a comparison of the literature reveals qualitatively different clogging behavior in different porous media: in granular media filters, increasing clogging is associated with slower flow, more flocculated conditions, and smaller fractal dimensions. In soils and dead-end membranes, increasing clogging is associated with faster flow, more dispersed conditions, and larger fractal dimensions. This paper documents these differences, discusses them in light of two key intermediate variables, colloid accumulation and deposit morphology, then presents a new conceptual model that explains the reported clogging phenomena as a function of specific deposit, fractal dimension, and a new variable, deposit location. Testing this model is possible using recently introduced experimental techniques.     

分光光度-遗传算法同时测定锌、镉、钴、镍、锰

在pH9.3,乳化剂OP存在下,Zn2+,Cd2+,Co2+,Ni2+,Mn2+与5-Br-PADAP发生灵敏的显色反应,所形成的三元胶束络合物的吸收光谱严重重叠,单独测定相互干扰严重。本文将分光光度法与遗传算法相结合,对同一混合体系的总吸光度值进行解析,实现了5种组分的同时测定。模拟样品测定的相对误差一般小于±10%。     

Management of Fluid Mud in Estuaries, Bays, and Lakes. I: Present State of Understanding on Character and Behavior

Fluid mud is a high concentration aqueous suspension of fine-grained sediment in which settling is substantially hindered. It constitutes a significant management problem in rivers, lakes, estuaries, and shelves by impeding navigation, reducing water quality and damaging equipment. Fluid mud accumulations have been observed in numerous locations worldwide, including Savannah Harbor, U.S., the Severn Estuary, U.K., and the Amazon River Delta, Brazil. This paper describes the present state of knowledge on fluid mud characteristics, processes, and modeling. Fluid mud consists of water, clay-sized particles, and organic material and displays a variety of rheological behaviors ranging from elastic to pseudo-plastic. It forms by three principle mechanisms: (1) the rate of sediment aggregation and settling into the near-bottom layer exceeds the dewatering rate of the suspension; (2) soft sediment beds fluidized by wave agitation; and (3) convergence of horizontally advected suspensions. Once formed, fluid mud is transported vertically by entrainment and horizontally by shear flows, gravity, and streaming. If not resuspended, it slowly consolidates to form bed material. Quantitative relationships have been formulated for key fluid mud formation and movement mechanisms, but they rely on empirical coefficients that are often site- or situation-specific and are not generally transferable. Research to define general relationships is needed.     

Review of The handbook of constructive therapies: Innovative approaches from leading practitioners.

Reviews the book, The handbook of constructive therapies: Innovative approaches from leading practitioners by Michael F. Hoyt (see record 1998-07937-000). The range of therapies fitting within the "constructivist" rubric includes (but is not limited to) narrative, solution-focused, solution-oriented, possibility, dialogic, reflective, and various aspects of family therapy. How does one teach-or learn-constructivism? A handbook, after all, is designed as a guide that tells you how to do things. For some of these authors, constructivism is an attitude, a perspective, a way of listening and being in dialogue. It is evanescent, in the unique moment. Others share specific techniques, some of which have become nearly reified through workshop presentations. Taken as a whole, these chapters work both within and across each other, comparable to the effective functioning of reflecting teams. The many voices complement and add further meaning. Most chapters are engagingly and clearly written, inviting the reader to further comprehension. Case examples, some in considerable detail, add to that understanding. As the chapters intersect and "speak" to each other, the reader can reflect on the "meta issues": the role of therapist, who is therapist, what is therapy, and what is therapeutic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)