冷轧钛带卷裂纹缺陷分析

对冷轧钛带卷典型裂纹缺陷进行了统计分类,采用化学分析、能谱分析、电镜扫描、硬度检测、金相组织观察对裂纹缺陷进行分析,揭示了冷轧钛带卷裂纹缺陷产生的原因.结果表明,钛卷基体铁元素、氧元素、氮元素含量偏高均可导致冷轧钛带卷出现裂纹缺陷.     

EB锭焊管用TA2冷轧钛带制备技术研究

TA2薄壁钛焊管具有比强度高、耐腐蚀、生产效率高、换热效果好等优点,被广泛应用于核电、化工、海水淡化等领域。本研究采用短流程、低成本电子束冷床熔炼炉EB扁锭制备焊管用TA2冷轧钛带卷,并对其组织性能进行分析。结果表明:采用EB锭制备的TA2冷轧钛带卷横向强度低、伸长率及表面硬度高,可有效避免焊管弯曲成型过程中表面划伤、磨痕等成型缺陷,满足薄壁焊管使用需求。      

室温ECAP和冷轧复合变形工业纯钛的组织和性能

采用ECAP技术和常规冷轧复合变形工艺制备了高强度工业纯钛,研究了复合变形后试样的力学性能与显微组织的关系.结果表明,工业纯钛经室温单道次ECAP和冷轧复合变形后,晶粒被严重拉长,形成了明显的纤维状组织,试样的抗拉强度高达805MPa;随着冷轧变形量的增大,变形组织的细化程度和均匀性提高,使试样的强度和塑性进一步提高.位错滑移和孪生是工业纯钛室温ECAP和冷轧复合变形的主要变形机制.     

冷轧钛带卷黑点缺陷分析及控制

利用扫描电镜对冷轧钛带卷退火后黑点进行了分析,分析表明:冷轧钛带卷黑点主要是由于,轧制时乳化液中含有固体小颗粒残留在卷材表面压坑处,脱脂时未脱干净退火后形成。针对性制定了控制措施,采用控制措施后冷轧带卷退火后黑点比率显著降低。     

TA1无缝管冷轧裂纹分析

通过宏观检查、金相分析、显微硬度测量、扫描电镜观察,分析了TA1无缝管在冷轧过程中出现较严重裂纹的原因。分析表明,在纯钛管裂纹附近区域夹杂的不连续颗粒状的硬α相是导致管材在冷轧过程中开裂的主要原因。     

纯钛丝脆断原因分析

采用化学成分分析、金相检验、力学性能测试及断口微观形貌分析的方法,对纯钛丝在拉丝过程中的脆断问题进行了分析。结果表明:造成纯钛丝脆断的主要原因是钛丝中的氮含量超出海绵钛化学成分国家标准的要求,氮含量偏高导致拉丝过程中的加工强度增加,塑性降低;显微组织的不均匀性及缺陷也会导致钛丝在拉丝过程中容易脆断。     

A32/A36船板钢拉伸试验分层缺陷原因分析及冶炼工艺改进

A32/A36船板钢在拉伸试验后出现了分层缺陷。利用光学显微镜、扫描电镜和能谱仪对分层缺陷严重的部位进行了分析。结果表明:分层缺陷主要与铸坯中存在元素偏析形成的铌、钛碳化物和硫化物夹杂有关。提出了改进冶炼和轧制工艺等相关措施并应用于实际生产,使废品率由12%降低到5%。     

钛板表面质量对钛-钢复合界面的影响

通过测试爆炸钛-钢复合板结合强度和分析钛板表面质量情况，研究了复合板中钛层产生分层、碎边和皱褶缺陷的原因。结果表明，钛板上残留的冶金缺陷、板形不良和不均匀的边部致密氧化层残留，会造成复合板界面的结合不牢。针对复合时界面结合不牢的问题，提出了对钛板的质量管控和表面处理的适宜措施。     

TA2纯钛构件电流辅助旋压成形实验研究

目的 研究TA2纯钛板电流辅助旋压成形工艺参数的影响,对变形过程进行分析。方法 在1 mm纯钛板的旋压过程中,电源、钛板和工具头构成电流回路,钛板局部温度迅速升高,工具头和旋轮协同导电加热旋压变形。试验了TA2纯钛板在室温和不同电流辅助下的旋压成形性能,在此基础上试验并分析了不同润滑条件下的旋压件表面质量。结果 在电流辅助旋压成形过程中,曲母线形件旋压变形过程为剪切变形,壁厚偏离率会影响钛板失稳起皱和反挤等缺陷。由电塑性效应可知,电流对纯钛板成形性能有着显著的影响,纯钛板的塑性变形能力随电流的增加而增强;二硫化钼作为一种理想的高温润滑剂,可以降低摩擦因数,提高旋压件的表面质量和工具头的使用寿命。结论 实验发现电流辅助旋压可以显著提升纯钛板的成形性能,表明该技术是可行的,且易于控制操作。     

利用陶瓷辊轧制钛带

利用传统的钢辊冷轧钛时,轧辊表面上的钛覆盖层厚度明普地增加,导致辊面粗糙不平,引起摩擦系数和轧制负荷提高,以至必须经常更换轧辊,造成钛带生产率下降,也难以提供所希望的高表面质量.     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

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.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.