Abrasive wear properties of compressed sugi wood

We examined the abrasive wear properties and the effect of abrasive grain size on the rate of wear when sugi wood (Cryptomeria japonica D.Don), compressed to various densities, was rubbed with abrasive paper. The results showed that the wear resistance of compressed wood increased linearly with the increased compression ratio; and under the condition of a low compression ratio it tended to be higher in comparison with the strength of compressed wood. The critical grain size effect, which can be witnessed during the abrasive wear of metals and plastics, was seen when low pressure was applied to the abrasive material. At higher pressures, the wear rate of the compressed wood increased with grain size, but the critical grain size effect was not observed. The pressure required to create the critical grain size effect was found to be higher than that needed for other types of uncompressed wood with the same yield properties.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

Optimization of Structure Parameters in Ultra-precision Plane Honing

The structure parameters of honing wheel have effects on machining accuracy in ultra-precision plane honing. This paper put forward to the optimization of structure parameters. By calculating the machining accuracy coefficient and wear coefficient of triangle radial structure honing wheels, it is obvious that the suitable triangle radial structure honing wheel can improve machining accuracy of workpiece.     

生物质固体燃料成型机压辊磨损失效分析

针对生物质固体燃料成型机在加工成型燃料过程中,关键部件环模和压辊磨损后导致使用寿命短、影响生产率等问题,该文对压辊进行磨损试验研究,该压辊采用45钢渗碳处理,渗碳层深度3 mm,在实际生产工况下工作200 h。由于原料中的硅酸盐成分、杂质、喂料的不均匀以及原料中水分影响加剧压辊表面的磨损,致使压辊快速磨损失效。磨损后利用S-570扫描电镜观察其磨损形貌,探究压辊失效的磨损机理。结果表明,靠近喂料一侧压辊表面磨损严重,磨损量4.2 mm左右,比其他位置表面的磨损量多1.2 mm。磨损机理主要是黏着磨损和磨粒磨损,磨损面已接近渗碳层与基体交界处,并且磨损面存在应力腐蚀裂纹。     

环模制粒机环模磨损计算及分析

在环模与压辊的互相挤压和环模与饲料间的摩擦力作用下,环模的主要失效形式是磨料磨损,依据疲劳磨损计算模型,建立磨损率计算公式,确定计算公式中的参数,并用实例讨论了各参数对磨损和生产能力的影响,为进一步研究环模耐磨损设计提供依据。     

激光熔覆Ni基合金/碳化物涂层组织及冲刷腐蚀磨损性能

在2Cr13马氏体不锈钢基材上激光多道搭接熔覆Ni—Cr3C2和Ni—WC复合涂层,考察两种激光熔覆层的微观组织、显微硬度对冲刷腐蚀磨损性能的影响,并与不锈钢基材对比。试验结果表明,两种涂层具有不同的凝固组织特征。含有未完全溶解WC硬质相的Ni—WC涂层比Cr3C2硬质相完全溶解的Ni—Cr3C2双相涂层的显微硬度高出约300HV,两种激光涂层的冲刷腐蚀磨损速率分别比不锈钢基材降低30％和60％。冲刷腐蚀磨损抗力的提高与熔覆层的组织状态、碳化物种类和数量以及涂层的韧化性能等因素密切相关。     

射流泵在含沙水流中抗磨损性能优化

为减小射流泵装置在含沙水流中运行时射流泵遭到的磨损破坏,对射流泵的抗磨损性能进行优化.首先提出了一种经济有效的材料表面磨损情况预测方法,再利用该方法得到抗磨损性能最佳的参数组合.结合粒子垂直撞击平板试验与数值模拟结果,得到在特定材料(316L不锈钢)下的磨损等高线图,并通过不同喷嘴出口速度的垂直撞击平板试验对磨损等高线图的通用性进行了试验验证,结果证实该方法可用于预测.通过Plackett-Burman试验设计得到显著影响材料磨损情况的射流泵参数,利用D-optimal试验设计得到性能最佳的射流泵参数组合.结果表明,当射流泵的参数组合为喷嘴角度39.85°、面积比5.84、喷嘴直径18 mm时,射流泵的抗磨损性能和水力性能都达到最佳,即最大磨损深度8.6 μm、效率16.8%.根据最佳参数组合加工射流泵样机,验证了预测结果的可靠性,并通过扫描电镜对喷嘴处的磨损疤痕进行观察,结论与数值模拟分析结果一致.     

基于响应曲面法的氟塑料两相流泵优化设计

为提高氟塑料两相流离心泵的效率及降低磨损率,基于离散颗粒模型(DPM)对氟塑料两相流泵内部流场进行模拟仿真,结合FINNIE磨损模型,对泵叶轮的磨损情况进行预测,采用响应曲面法,以叶轮的主要几何参数为变量,构建各优化目标的数学模型,利用Matlab绘制上述6个叶轮外形参数与各优化目标之间的3D响应面图形,并通过Matlab统一各数学模型,对SJB400-250-300型氟塑料离心泵叶轮的外形参数组合进行寻优,得到最优参数组合.研究结果表明,氟塑料离心泵叶轮的各外形参数之间存在交互性影响,当叶轮进口直径D₁、叶片包角φ、叶片进口安放角β₁、出口角安放角β₂、叶片出口宽度b₂取高水平,叶轮出口直径D₂取低水平时,能够获得更好的综合性能,优化获得模型相较于原模型,效率提升8.98%、磨损率下降了6.64%.通过对参数和优化目标间的交互关系进行分析总结,得到了叶轮各几何参数及各性能参数之间交互作用对优化目标的影响,为氟塑料两相流离心泵的性能优化设计提供依据.     

Corrosive-wear characteristics of diamond-coated cemented carbide tools

Continuous milling tests with diamond-coated and uncoated cemented carbide tools and polycrystalline diamond tools were carried out on air-dried and wet melapi (Shorea sp.) and western redcedar (Thuja plicata D. Don). These tools were examined for corrosive-wear characteristics of the tool-edge appearance, cutting-edge profile, edge recession, and cutting-power consumption. The tool surfaces were observed with a scanning electron microscope and were analyzed by energy-dispersive X-ray spectroscopy. Based on these examinations, the occurrence of corrosive wear while cutting wet woods was confirmed for the uncoated and polycrystalline diamond tools. In contrast, the coated tools did not exhibit corrosive wear, nor did delamitation or wear of the diamond film occur with any of the work materials. The diamond-coated tools showed high resistance not only to mechanical wear but also to corrosive wear.The results of this work were presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

高压磨料水射流切削

HP AWJM is a new cutting technology developed on WJM in the early 1980''s. With its development, a practical method has been provided for cutting the material with high strength and high hardness. In this paper, the equipment and its principle, testing res     

小波神经网络故障诊断系统的设计与应用

采用能量分布特征提取方法和优化BP算法，提出了一种基于小波变换和BP神经网络的故障诊断系统。利用该系统对汽车变速箱三挡齿轮磨损程度进行估计，诊断结果与实际完全吻合，表明该小波神经网络故障诊断系统的有效性。由于小波分析特别适用于非平稳信号的处理，因此该小波神经网络诊断系统对复杂机械设备的故障诊断有着广阔的应用前景。