智利纪行

智利以铜著称,是中国铜业关注的地方.尽管北京与智利首都圣地亚哥的距离是全球各国首都之间最远的两个点,但还是有一批又一批的考察团远渡重洋来到这个神秘的国度. 2008年4月,我随山东方圆集团组成的考察组从北京启程,经过两次转机与航行到达地球另一面的圣地亚哥.这是一次行程长达两万多公里,历时近36个小时,横跨了欧亚大陆、穿越非洲大陆、掠过大西洋、赤道线和南美洲的漫长旅行,再加上智利境内的考察航程,往返的行程累计起来可以绕地球一周了!     

阿基米得螺线系数选择对模拟钛弯管推扩成形的影响

采用MSC公司的Superform软件对不同阿基米得螺线系数下的热推扩进行了模拟.扩径段采用了3种不同的系数并分析了不同系数下对热推扩成形弯管的影响.结果表明:扩径变形段中心轴线采用曲率半径渐变的阿基米得螺线,有利于管坯凹面金属充分向凸面流动,避免了传统弯曲变形内侧受压增厚,外侧受拉减薄;阿基米得螺线系数a≤0.9时,环向厚度差大;a≥l.3时,容易出现起皱和45°剪切变薄.本试验范围内,a值取1.0最佳.     

国外废金属的主要分布区域

国外废金属主要分布在工业发达国家.按产生分布地区划分,大体可分为北美地区(美国、加拿大),欧洲地区(欧共体),东南亚地区(日本、韩国、台湾),俄罗斯及澳洲几大部分.     

调解的精髓在于双赢——中国国际商会调解中心为再生企业排忧解难

1987年,伴随着国际贸易、国际投资和国际经济合作业务的持续增长,各种商事纠纷和贸易摩擦的不断增加,中国贸促会成立了第一家商事调解机构--北京调解中心2000年北京调解中心正式更名为中国贸促会/中国国际商会调解中心. 中国贸促会/中国国际商会调解中心秉承"以和为贵"、"促进双赢"的调解理念,以调解的方式,独立公正地帮助中外当事人解决了大量的商事争议,成为中国商事调解领域一支最重要的社会力量.其现有中外籍在册调解员300 余名,有41家贸促会系统地方调解中心遍布在全国各地,形成了一个庞大的调解网络.整个调解网络的受案量已达 6 000余件,调解成功率达到80%.调解当事人涉及50多个国家和地区.     

梦醒在开始的地方再生产业从风雨迷茫中一路走来

资源再生、循环经济在今天可谓风光无限:国家大力提倡,企业日益重视,再生产业吸引了全社会的目光.但在从新中国成立到改革开放后二十年的时间里,资源再生还是一个没有独立构成的行业,从业人员也往往因为每天与"破烂"为伍而被人看不起.     

2007年中国机床工具行业十大新闻

1. 中央和地方省市主要领导频繁视察机床行业企业,国家为数控机床产业发展创造了空前良好的发展环境. 胡锦涛、吴邦国、温家宝、贾庆林、李长春等党和国家领导人以及辽宁、黑龙江、山东、江苏、云南、湖北、广东、陕西、浙江、天津、重庆等省市主要领导相继视察了机床工具厂和数控系统厂.各级领导频繁视察,为数控机床产业的发展创造了空前良好的发展环境.     

透析营销失败的10大原因

经验主义,没有创新 　　一些企业或个人成功后,总是喜欢用过去的思路经营新的品种.殊不知任何新品都有差异性,他们的消费对象、产品的核心卖点及表现力均是不同的,经验主义很容易使产品销售走弯路,甚至导致营销失败.作为老产品,包装也要常更新,但要沿袭原有的核心记忆点与要素,才能使市场趋于稳定,甚至增长.……     

亚熔盐法回收赤泥

采用亚熔盐法对赤泥中的Al2O3和Na2O的回收进行研究.实验第一步通过采用亚熔盐和添加适量石灰乳液回收赤泥中的Al2O3,使其中Al2O3的含量降至4.19%,Al2O3单程回收率达88%;实验第二步采用低浓度的NaOH溶液对赤泥进行深度脱钠,使得最终赤泥中Al2O3和Na2O的含量分别降到3.88%和1.39%,Al2O3/SiO2和Na2O/ SiO2相应降到0.17和0.06;经过回收Al2O3和Na2O后的终赤泥呈现出表面疏松多孔的颗粒状形貌.本研究在较低温的条件下综合回收赤泥中的Al2O3和Na2O.     

灰铸铁主要元素变量三角试片白口宽度与抗拉强度数学模型的研究

在进行灰铸铁铸造生产时,通过不断采集同一浇包中铁液所浇注的三角试片白口宽度、主要化学成分及所浇注试棒的抗拉强度,在大量试验数据的基础上,逐渐摸索出三角试片白口的宽度和C、Si、Mn含量与其抗拉强度内在数量关系,用数学归纳法得出一个灰铸铁的主要元素C、Si、Mn三因素变量与三角试片白口宽度和抗拉强度的一次回归方程。借助回归方程能迅速地预测强度,指导配料,最大限度的降低铸件的成本。     

“表面工程行业清洁生产及节能减排新技术、新装备交流会”在北京召开

近日,北京表面工程学会在北航新主楼第八报告厅召开了“表面工程行业清洁生产及节能减排新技术、新装备交流会”,学会邀请了北京中如技术有限公司曹建岭高工和北京蓝丽佳美化工科技中心李家柱研究员作学术报告,交流会由北京表面工程学会理事长朱立群教授主持,学会理事及会员代表近40人出席.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

Simulation of 3-D Deformation and Material Flow During Roll Forging Process Using System of Oval-Round Groove

Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver.5.0 code. The important information concerned with the deformation area characteristic, material flow, and velocity field has been presented. Otherwise,the location of the neutral plane in the deformation area was shown clearly.     

Effects of Sub-zero Celsius Treatment and Tempering on the Stability of Retained Austenite in Bearing Steel

In this work, the influence of sub-zero Celsius treatment and tempering on the mechanical and thermal stability of retained austenite in bearing steel were assessed by tensile test and DSC. Compared with traditional quenched and tempered treatment, sub-zero Celsius treatment obviously decreases the volume fraction of retained austenite. Moreover, the mechanical stability of retained austenite was enhanced due to the accumulation of compressive stresses in retained austenite after sub-zero Celsius treatment and tempering. Meanwhile, the morphology of retained austenite changed from film-like to blocky with austenitization temperature increasing, and the mechanical stability of film-like retained austenite is higher than that of blocky one. The DSC results showed that the activation energy of retained austenite decomposition slightly increased through sub-zero Celsius treatment and tempering. This result may probably be ascribed to partitioning of carbon during tempering. However, the temperature at which retained austenite starts to decompose is unchanged.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Behavior of Ni‐base alloy 625 in methanol‐supercritical water systems

Methanol reacts with water under supercritical conditions to form a hydrogen rich gas. This reforming reaction can be performed without the addition of a catalyst. Typical reaction conditions are 25 MPa pressure and 600°C temperature and short residence times. The tubular flow reactor used was made of the nickel base alloy 625. The reactor was operated continuously for more than 1000 hours without problems. The feed concentration was 5 weight‐% methanol. The major component of the product gas was hydrogen (up to more than 70 vol‐%). Methanol conversion was higher than 99% and the liquid effluent was clear and free of soot. After exposure, the reactor has been sectioned and each section has been analyzed. No major corrosion phenomena were observed. Severe ductility loss of the material could be measured in the higher temperature section of the reactor.     

Effects of Tungsten and Boron Contents on Crystallization Temperature and Microhardness of Tungsten Based Metallic Glasses

Effects of tungsten and boron contents on the thermal properties and microhardness of W-Fe-B metallic glass system were studied. Thin foils, with thicknesses of 20 and 100 μm, of the alloys were produced by piston and anvil method in an arc furnace. The structures of the foils were investigated by X-ray diffraction. Thermal stabilities of the alloys were examined by using differential scanning calorimetry. 20-μm- thick foils of all the alloys were determined to be fully amorphous, but crystalline phases were detected in the 100-μm-thick foils. It was found that crystallization temperatures of the alloys are between 1060 and 1177 K. Tungsten and boron content increases improve the crystallization temperature and microhardness of the alloys significantly, but deteriorate the glass forming ability of the alloys. It was also observed that for constant Fe content, increasing tungsten content to the level higher than that of boron content does not result in any further improvement in crystallization temperature, but improves glass forming ability significantly. The alloy containing highest total amount of tungsten and boron, W₃₅Fe₃₅B₃₀, has the highest crystallization temperature, 1177 K, and microhardness, 1634 HV.     

Formation of Nano/Ultrafine Grains in AISI 321 Stainless Steel Using Advanced Thermo-Mechanical Process

Production of nano/ultrafine grains through deformation-induced martensite formation and its reversion to austenite in an AISI 321 stainless steel was studied.The repetitive cold rolling and subsequent annealing were conducted to obtain nanocrystalline structure.Heavy cold rolling(90% reduction) at ?20 and-20 °C was carried out to induce the formation of a9-martensite from metastable austenitic material.The process was followed by annealing treatment at700–900 °C for 0.5–30 min.Effects of process parameters,i.e.,‘‘reduction percentage,' ‘‘rolling temperature,' ‘‘annealing temperature' and ‘‘annealing time',on the microstructural development were considered.Microstructural evolutions were conducted using feritscope,X-ray diffractometer and scanning electron microscope.Hardness of the specimens was measured by Vickers method.Results revealed that the higher thickness reduction and lower rolling temperature provided more martensite volume fraction and further hardness.X-ray diffraction patterns and feritoscopic results indicated that saturated strain(es) was reduced from 2.3 to 0.9 when temperature declined from ?20 to-20 °C.The smallest grain size(about 70 nm) was achieved in the condition of cold rolling at-20 °C followed by annealing at 750 °C for 5 min.