SiC基材料自身及其与金属的连接

SiC及SiC基复合材料作为先进高温结构陶瓷材料的典型代表，具有广阔的航空航天应用前景，研究SiC及SiC基复合材料的连接以及这些材料与金属的连接问题不仅具有重要的科学意义，而且具有极大的工程应用价值。本文综述了有关SiC及SiC基复合材料自身连接及其与金属连接的基本问题——陶瓷与金属连接的热错配应力、陶瓷与金属的润湿行为及陶瓷与金属接头界面问题，并介绍了几种主要的连接工艺——固相压力扩散焊、活性金属钎焊、局部过渡液相连接法、反应成形法、自蔓延高温合成焊接法及热压反应烧结连接法。     

Progress in Joining Ceramics to Metals

With low density,high strength and excellenthightemperature resistance,ceramics are used wide-lyin areas of aerospace and metallurgy.Especiallyinhigh temperature techniques,ceramics and ceramicmatrix composites possess more advantages thanmetals.But ceramics has lowtoughness and is hardto manufacture complex parts.Therefore,it is rea-sonable to manufacture composite parts of ceramicsand metals by joining to meet the requirements[1,2].The development of several joining methods es-pecially joini…     

Process Strategies and Analysis of Rolled‐in Tubes

A new method to manufacture composite workpieces is joining of two parts by rolling‐in, a technique which has been developed at the Department of Machining Technology (ISF) and at the Institute of Forming Technology and Lightweight Construction (IUL). In this article, the technology is described and different strategies to shorten the joining process without a decrease of the strength of the composite are presented and compared. To improve the knowledge about the material flow, the strain distribution in the contact zone has been analysed both experimentally and by means of finite element analyses (FEA). In order to evaluate the strength of the composite, an analysis of the press‐out forces and of the residual stresses in the inner tube has been carried out, also by means of experiments and simulations.     

Pulsed‐Magnetic Hot Joining ‐ New Solutions for Modern Lightweight Structures

To further significantly reduce the car weight, new and innovative production technologies are necessary which allow to join aluminium and – in the future – magnesium profiles. Then it will be possible to connect components made of aluminium or magnesium base alloy with steel parts to one group. Such a new technology is pulsed‐magnetic joining. In order to lower the process forces necessary for pulsed‐magnetic joining of high strength aluminium alloys and in order to establish a technologically useful forming of magnesium alloys, joining at increased temperatures appears to be a viable solution. As part of the research a tool for pulsed‐magnetic hot joining has been developed that combines the processes of heating by induction and pulsed‐magnetic joining. The applicability and the potentials of the tool have been demonstrated with hot joining of aluminium and magnesium profiles. The combination of the techniques allows for the first time to join magnesium profiles with forming by using pulsed‐magnetic forming at high temperatures. Regarding aluminium the combination of the techniques allows a significant reduction of the magnetic pressure that is necessary for the forming process; it thereby increases the operating life of the tools.     

钨合金砧模与基座联结方式的效益分析

介绍了钨合金砧模的工作特性，分析了钨合金砧模与基座的几种联结方式的优、缺点。指出：自锁式V型联结，砧模与基座间始终保持紧密接触，具有自锁作用，故模的导电性及散热性良好，使用寿命明显提高，可取得较好的经济效益。     

圆管二次辊弯成形过程中的大变形有限元法模拟

应用弹塑性三维大变形有限元理论，同时考虑材料和几何双重非线性，基于Ｐｒａｎｄｔｌ－Ｒｅｕｓｓ流动规律和Ｍｉｓｓ屈服准则，并采用Ｕｐｄａｔｅｄ－Ｌａｒｇｒａｎｇｉａｎ增量叠加法分析了不同压下量成形过程中金属由非稳态到稳态的流动规律，然后通过有限元程序实现了计算机模拟。模拟结果为ＣＡＤ（计算机辅助设计）及ＣＡＭ（计算机辅助制造提供了重要理论依据，同时还可以指导实际生产过程，对提高产品的质量和经济效益有     

试述入世对我国钢铁企业的影响及对策

通过分析加入世界贸易组织后，我国钢铁工业的发展及可能发生的变化，简述了国内外钢铁市场的供求状况及企业面临的挑战，探讨了国内钢铁企业的应对策略。     

板带热轧无头轧制技术分析及其应用进展

介绍了热带无头轧制技术概要、工艺效果和无头轧制在板带高精度轧制技术中的作用，重点分析了无头轧制的中间坯连接技术、板厚、板形和品质控制技术以及在极薄热轧带钢生产和热轧超深冲钢板生产上的应用成果，指出无头轧制在高品质热轧薄板新产品生产方面的应用前景和有关无头轧制新技术的研究开发课题。     

球磨机进料器与中空轴联接螺栓断裂原因分析

球磨机进料器与中空轴联接螺栓断裂原因是进料器与中空轴之间间隙过大 ,密封锥面受矿浆冲蚀而被破坏。根据生产实际 ,找到了取出断裂螺栓的方法 ,缩短了检修时间 ,并提出了预防中空轴进浆的措施。     

缓倾斜露天矿顺倾向采矿法的改进

张钢油田石灰石矿根据矿山实际情况对缓倾斜露天矿顺倾向采矿法进行改进，采用由上而下顺倾向与水平分段相结合，横向爆破，沿走向运输，多台阶伺步推进的采矿方法，使矿石回采率达到95％以上，贫化率低于1％，年创经济效益近10万元。     

Thixo‐Forging and Thixo‐Joining of an Integrated Product

In an effort to investigate thixo‐joining of aluminium alloy AISi7Mg with bolts of different metals, a series of experiments was carried out. An aluminium master part of high geometric complexity was thixo‐forged. Then thixo‐joining experiments were conducted. While the thixo‐forging of the aluminium master part being completed, bolts of brass, copper, plain carbon steel and stainless steel were integrated into the thixo‐forged part in one step. Evaluations of the produced parts were performed with X‐ray inspection, microstructure and segregation analyses. The experimental results confirm that the aluminium alloy A356 has good formability in semi‐solid state and that the thixo‐joining of the metal bolts with the aluminium part in one step is feasible.     

Mechanical properties of ultra-high-strength steels at elevated temperatures

ABSTRACT

This paper presents an experimental study on the mechanical properties of ultra-high-strength steels at elevated temperatures. Tensile tests were carried out at 300–600°C on Docol 1200M and Docol 1400M steel samples. The results indicate that as the temperature increases Young’s Modulus, yield strength (YS) and ultimate tensile strength (UTS) display a decrease. YS/UTS ratios at 300°C are lower than those at room temperature, they make peaks at 400 and 500°C for Docol 1400M and Docol 1200M, respectively, and then decrease again beyond those temperatures. While total elongation continuously increases, uniform elongation slightly decreases with increasing temperature. Present carbides in tempered matrix continue to grow and new carbides are observed at the grain boundaries. Considering all roll forming parameters, 300°C seems the most convenient temperature for warm forming. In this sense, the warm roll forming has a potential for forming complex-shaped parts by reconciling strength with formability.     

以Nb为中间层AgCuTi为钎料连接炭/炭复合材料与不锈钢

在连接温度为900℃、保温时间10 min的条件下,以Nb为中间层,采用AgCuTi钎料对炭/炭复合材料与不锈钢进行连接.利用扫描电镜和X射线衍射对接头界面组织进行分析.实验结果表明,以Nb为中间层、AgCuTi为钎料能很好地连接炭/炭复合材料与不锈钢;连接过程中,钎料中的Ti向炭/炭复合材料界面区聚集并形成含TiC的...     

Metal Forming of Vibration‐Damping Composite Sheets

Composite materials with vibrations damping qualities can be made of two steel sheets enclosing a viscoelastic plasticcorelayer. These sandwich sheets often need to be formed. Material parameters are determined to describe the forming process. Based on these parameters, pilot studies are carried out in order to develop recommendations for forming this class of material.     

合金化热镀锌钢板冲压后表面小亮点的成因分析

简介了合金化热镀锌钢板在冲压后出现小亮点缺陷的试验研究，据此进行了调查、分析以及模拟冲压试验，找出形成小亮点缺陷的一个直接原因，并提出了相应的改进措施。     

Influence of Mandrel's Surface and Material on the Mechanical Properties of Joints Produced by Electromagnetic Compression

Electromagnetic compression of tubular profiles with high electrical conductivity is an innovative joining process for the manufacturing of lightweight structures. The mandrel's material has an influence on the transferable loads which is affected by the Young's modulus as well as the strength of the material. This was investigated, on the one hand, by changing the mandrel's material and, on the other hand, by using the same mandrel material with differing strength. Furthermore, taking conventional interference fits into account, the contact area's influence on the joint's quality seems to be of significance, as e.g. the contact area and the friction coefficient between the joining partners proportionally determine an allowed axial load or torsional momentum. Therefore, different contact area surfaces were prepared by shot peening and different machining operations and strategies. The mandrel's surfaces were modified by shot peening with glass beads and Al₂O₃ particles. An alternative preparation was performed using simultaneous five‐axis milling, because potential joining partners in lightweight frame structures within the Transregional Collaborative Research Centre SFB/TR10 would be manufactured similarly. After that, the manufactured surfaces were characterized by measuring the surface roughness and using confocal whitelight microscopy. Afterwards the modified mandrels were joined by electromagnetic compression. The influence of different mandrel's surface conditions on the joint's mechanical properties was analysed by tensile tests. Finally, conclusions and design rules for the manufacturing of joints by electromagnetic compression are given.     

连续退火工艺对冷轧马氏体钢板力学性能的影响

 冷轧马氏体钢采用水淬退火机组生产,可以节约合金元素,同时获得高强度,符合汽车用钢高强度和减重节能的要求。以冷轧低碳马氏体钢为研究对象,研究了连续退火工艺对马氏体钢板力学性能的影响,发现淬火温度、缓冷速度和回火温度均对马氏体钢的强度有很大影响。在奥氏体缓慢分解的较高温度区间开始淬火有利于马氏体钢强度的稳定。回火降低马氏体钢的抗拉强度,对屈服强度有提高的作用,在200~300℃之间回火,冷弯性能基本不变或有所提高,未发现在240℃以上过时效出现显著的冷弯性能下降的现象。