Application of Abrasive Water Jet Perforation Assisting Fracturing

This article presents a new technology of abrasive water jet perforation assisting fracturing on Well Zheng 408-8, Bin Nan Production Plant, Shengli Oilfield. First, the balsting tool, with 9 nozzles, was lowered down to the payzone and perforated 90 tunnels with abrasive water jet after being moved upward 9 times. Then the fracture work was conducted and 18 m³ sands were squeezed into the formations. After that the well production reached 11.6 t/d liquid and 8.7 t/d oil, respectively, and this continued for 9 months. But before the job, nothing was produced from this well.     

壳体镶套修复研究

介绍了镶套工艺在壳体修复中的应用     

Investigation of tribotechnical and service characteristics of diamond-containing materials based on SHMWPE and PTFE

Investigation results of service characteristics (specific consumption of diamonds, machining capacity, glazing of tools) of diamond abrasive materials based on high-molecular polyethylene and polytetrafluoroethylene are discussed. Optimum graininess and concentration of microgrit as well as conditions of steel and mineral material machining have been evaluated for both binders. It is shown that the tools based on PTFE are advantageous for a short-time grinding of steels, while the ones based on SHMWPE are better for a long-run grinding of minerals and steels.     

Three-body abrasive wear behaviour of particulate-filled glass–vinyl ester composites

The incorporation of silicon carbide (SiC) and graphite fillers on three-body abrasive wear behaviour of glass–vinyl ester (G–V) composites has been investigated. Dry sand/rubber wheel abrasion tests (RWAT) were carried out at 200 rpm test speed. The tests were carried out at 22 and 32 N loads by varying the abrading distance from 270 to 1080 m in steps of 270 m. The worn surfaces were examined using scanning electron microscopy (SEM). The wear volume and specific wear rate of G–V composite reduces significantly on the addition of SiC filler. Graphite filler, however, performed poorly resulting deterioration in wear performance of SiC-filled G–V composite. The SEM studies indicate the reasons for failure of composites and influencing parameters.     

闸底板抗磨防冲的新方法——利用废旧轮胎保护闸底板

新疆阿克苏河协合拉引水枢纽在闸底板抗磨防冲中,总结"以硬制硬"效果不佳的教训,利用废旧轮胎耐磨抗冲的特点,用于多卵石河道上闸底板抗磨防冲"以柔克刚",取得了良好的效果,为多卵石河道的防冲抗磨提供了成功的经验.     

The Comparative Appraisal of Quality Characteristics of Holes after Different Finishing Methods

Magnetic abrasive machining (MAM) of internal surfaces is a less studied process than machining of external surfaces. The present study contains MAM principles of round internal parts. The finishing method MAM forms optimum physical-mechanical properties of surface layer parts which are most relative to operation. The article contains comparative data of quality characteristics of parts from steel 45 and 12X2H4A after grinding, honing and MAM. It states the peculiarities of roughness formation of surface and its physical-mechanical characteristics after mentioning finishing methods.     

基于oldroyd-B本构模型的磨料流加工壁面滑移仿真分析

基于oldroyd-B粘弹性本构模型,应用POLYFLOW软件对流体磨料在圆管中的壁面滑移状态进行了模拟仿真。将得到的圆管中流体磨料的压力值与磨料流加工机床上测试点的压力值进行比较,得到二者的相对误差不超过5%,验证了模拟仿真的可行性。通过仿真可知,流体磨料在工件壁面上的滑移存在速度临界点。通过比较不同管道入口流量、流体磨料黏度和壁面滑移系数对壁面滑移速度的影响可知,当管道入口流量越大、流体磨料的黏度越高,以及壁面滑移系数越小时,加工过程中的壁面滑移速度越大。     

基于C#.NET的树脂磨具CAD/CAM集成系统设计与开发

针对我国磨具设计水平与手段落后的现状,提出开发面向树脂磨具生产制造的CAD/CAM集成系统。通过分析树脂磨具的制造工艺过程,论述了该系统的总体架构和具体功能模块设计。在此基础上,开发了基于C#.NET的树脂磨具CAD/CAM集成系统,为提高中小型磨削工具制造企业的设计制造水平和效率提供了信息化平台。     

脉冲电磁场辅助平面磁粒研磨加工试验

目的在传统的平面磁粒研磨加工中添加脉冲辅助磁场,增大加工区域中磁感应强度和加工时磁感应强度动态变化,丰富磨料粒子在加工时的运动形式,使研磨轨迹复杂化,降低工件表面粗糙度,获得更好的工件表面形貌。方法通过分析磨料粒子在有无辅助磁场时各自的受力情况,探究辅助磁场对磨料在加工时运动状态的影响,研究脉冲辅助磁场下磨料的运动行为机理。利用Ansoft Maxwell软件对电磁铁不同形状的磁极头产生的磁场进行模拟对比,确定理论上最优的磁极头形状。同时模拟对比脉冲电流在不同时刻加工区域内磁感线的分布情况,以及恒定磁场和脉冲磁场下磨料的运动轨迹。通过试验对比无辅助磁场、恒定辅助磁场和脉冲辅助磁场下磁粒研磨加工SUS304不锈钢的表面形貌和表面粗糙度。结果在磁粒研磨加工中,磁性磨料分布受磁感线的影响,在脉冲辅助磁场的作用下加工区域内的磁性磨料会随磁感线的变化而做周期性的往复运动,加工时会有更为复杂的研磨轨迹。模拟3种不同形状的磁极头在加工区域产生的磁感应强度曲线,平面、圆锥面和半球面在中点处的磁感应强度峰值分别为655、636、702 mT。以SUS304不锈钢板作为试验对象,原始表面粗糙度为0.46μm,采用半球形的电磁铁磁极头,在研磨间隙为2 mm、永磁极转速为800 r/min、进给速度为5 mm/s的试验条件下,对比电磁铁不通电、通入0.8 A直流电流、通入1 Hz,占空比50%,峰值电流0.8 A的单向脉冲电流3种辅助磁场分别对工件研磨30 min后的工件表面形貌,无辅助磁场时工件表面仍残留一些原始纹理;恒定辅助磁场下工件表面原始纹理被去除,但表面存在明显圆弧形研磨痕迹;脉冲辅助磁场下工件表面形貌更为光整、平滑。研磨后工件表面粗糙度分别降至0.28、0.13、0.06μm。结论脉冲磁场辅助磁粒研磨在提高加工区域磁感应强度的同时,可使磁性磨料在加工时做周期性运动,研磨轨迹复杂化,促进了磨料的更新,相比传统磁粒研磨和恒定辅助磁场磁粒研磨工艺,脉冲磁场辅助磁粒研磨加工后的工件表面形貌更加平滑,表面粗糙度更低。     

磨料射流加工技术的发展与研究现状

与其他加工技术相比,磨料射流因具有无热损伤、高柔性、材料适用性强等特点,一直是国内外学者研究的热点。近年来,磨料射流被广泛用在微切割、微流道制备、表面抛光等领域,其发展趋势已经由宏观尺度向微观尺度转变,由粗加工向精加工转变。从射流的本质或根源来看,传统技术主要分为(磨料)水射流、浆体射流和磨料气射流。首先对上述各射流技术的发展背景、工作原理进行了综述。此外,还介绍了最近出现的多相射流和高压浆体射流等新技术。面对复杂的应用需求,如何挑选出合适的射流技术是一个难题。鉴于此,对各磨料射流技术的射流速度、工作压力、射流束直径、侵蚀轮廓和加工机理进行了深入分析和比较。最后对各磨料射流技术在微流道制备和表面光整加工等领域的应用情况以及存在的问题进行了论述,并详述了多相射流和浆体射流在表面抛光方面的优缺点。结果表明,磨料气射流拥有低压高速的优点,可以快速地去除材料。磨料气射流的缺点是射流易发散,需要结合掩模制备微流道。目前,掩模磨料气射流能加工宽度低至10 μm的微流道。浆体射流和磨料水射流的射流束直径已经可低至50 μm,能直接在表面刻蚀出大于50 μm的微流道。抛光应用中,浆体射流的材料去除率远低于磨料气射流,但表面粗糙度要好。考虑到两者的优点,多相射流试图在磨料气射流和浆体射流之间建立一个桥梁。同时,与浆体射流的W形侵蚀轮廓相比,多相射流的U形侵蚀轮廓更有利于表面抛光。