倾斜煤层工作面单体防倒组合支架的研究与应用

介绍专为倾斜煤层采煤工作面研制的单体防倒组合支架及其应用效果。实践表明,它能有效地解决大倾角工作面单体支护的一些安全问题。     

Biaxiale Ermüdung reibrührgeschweißter Strukturelemente

Biaxial fatigue of friction stir welded stiffened panels Within the framework of the European WelAir project, cruciform specimens made from stiffening FSW overlap joints were fatigued in the DLR biaxial test rig. To resemble the loading situation of pressurized fuselage structures, proportional loading without any phase shift, but with different load ratios λ between the loading components in both directions was applied.Natural crack initiation and subsequent crack growth were governed by the stiffness gradient caused by introducing the stringer. Cracks initiated and propagated at run‐in and run‐out locations in a direction perpendicular to the weld seam. The shortest fatigue life was observed for uniaxial loading in welding direction (λ = 0). An additional stress component perpendicular to the joint line (λ > 0) resulted in a higher number of cycles to failure. Similar to single stringer panels, increasing the load ratio also increased the number of cycles to failure for FSW clip‐stringer structural members, but additionally gives a different location of the fatal crack.     

海洋平台双相不锈钢管线的焊接

就双相不锈钢的特异性能．介绍双相不锈钢管线的焊接特点与技术。     

Influence of Ni Interlayers on the Mechanical Properties of Ti6Al4V/(WC-Co) Friction Welds

Ni interlayers were introduced prior to dissimilar friction welding of Ti6Al4V base material to three cemented carbide substrates. The fracture strength of Ti6Al4V/(WC-6 wt% Co) welds were poor and were markedly improved when 20-µm thick Ni interlayers were introduced prior to dissimilar friction welding. These results were only produced when the (WC-6 wt% Co) cermet was electroplated prior to friction welding. When the Ti6Al4V alloy was electroplated prior to friction welding, fractured WC particles and cracking were observed in the (WC-Co) carbide substrate. The fracture strengths of Ti6Al4V/(WC-11 wt% Co) and Ti6Al4V/(WC-24 wt% Co) welds were not improved when 20-µm thick Ni interlayers were introduced prior to friction welding. During mechanical testing, the Ni layer retained at the dissimilar joint interface created a region of weakness.     

唐钢ER70S-6焊丝钢的生产工艺研究及质量分析

介绍了唐钢ER70S-6焊丝钢的特点，对盘条质量进行了分析。对该钢化学成分、冶炼和轧制工艺进行了优化研究，使其综合性能明显改善。     

钻机绞车滚筒体的窄间隙埋弧焊

针对钻机绞车滚筒体采用手工电弧焊工人劳动强度大、焊接效率低、质量不稳定及返修率高等问题,研制了钻机绞车滚筒体窄间隙埋弧焊专机。该专机由ESAB—A2埋弧焊电源和焊接小车、窄间隙焊头、滚轮架、防窜装置、旋转地线夹、三维焊接工作台、焊剂自动回收机组成。使用表明,采用该焊机焊接的滚筒体焊缝质量完全符合设计要求,合格率100%,焊接效率比原来提高6倍。每件滚筒体的焊接可降低人工成本约80%。     

爆炸焊接边界效应的力学能量原理

在爆炸焊接工艺中,存在一种称为边界效应的物理现象。即在一般情况下,在爆炸焊接后的复合材料中,会出现雷管区不复、其余周边被打伤、打裂和变形严重等问题。这些问题严重地影响着这类材料的质量。该文从传统的和经典的力学及能量原理出发,探讨了边界效应产生的力学 能量原理,并且提出了预防的措施。     

穿壁焊极柱合金探索

本文对起动用铅酸蓄电池穿壁焊极柱用合金配方进行了探索 ,并得到了良好的应用效果     

Finite elements in the analysis of pressure vessels and piping-a bibliography (1976–1996)

The paper gives a bibliographical review of the finite element methods (FEMs) applied for the analysis of pressure vessel structures/components and piping from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore the aim of this review is to give the reader an encyclopaedic view of the differnt possibilities that exist today for the finite element analysis in the fields of pressure vessels and piping. The bibliography at the end of the paper contains approximately 1900 references to papers, conference proceedings and theses/dissertations on the subject that were published in 1976–1996. These are classified in the following categories: linear and non-linear, static and dynamic, stress and deflection analysis; stability problems; thermal problems; fracture mechanics problems; contact problems; fluid-structure interaction problems; manufacturing of pipes and tubes; welded pipes and pressure vessel components; development of special finite elements for pressure vessels and pipes; finite element software; and other topics. Also finite element software, general purpose and special purpose codes, used for the analysis of pressure vessels and pipes are briefly discussed and presented.     

An investigation of pore cracking in titanium welds

Two welded Ti-6A1-4V pressure vessels leaked prematurely in service. The leaks were caused by cracks emanating from weld porosity. The cracks originated during fabrication, with subsequent growth in service leading to the formation of the leak paths. Pore cracking is thought to be caused by a mechanism that involves both sustained-load and cyclic contributions, with the former being the more prominent. It is shown that the tendency for cracking is influenced by pore position and that pore size is not a deciding factor in that regard. The factors that govern pore cracking are discussed, and the possible role of interstitial embrittlement is assessed.