汽车车灯配光面片的快速逆向建模

针对汽车车灯反射器配光面片手工造型时效率不高的问题,开发了自动生成与调节配光面片的逆向建模,实现配光面片逆向造型的自动化。实验证明,逆向建模可以大大提高面片的过点精度和造型效率。     

Optimization of spraying process and laser treatment of CoNiCrAlY

This article describes the investigation of a new generation of vacuum plasma sprayed CoNiCrAlY coatings on NiCr20Ti in the sprayed as well as the laser-treated condition. The aim of the study was the improvement of MCrAlY coating properties by modifying the microstructure through laser remelting with 5-kW Co₂: lasers. Parameter analysis and optimization was carried out for the vacuum plasma spraying process, as well as for the laser remelting technique. The effect of the laser treatment on microstructure, quality of the coatings, and oxidation as well as hot gas corrosion behavior are reported.     

等离子无模成形叶轮的应力场分析与校核

等离子熔积无模成形是急速加热快速凝固的短流程制造技术,如何避免制件的热裂纹是该技术的关键,而热裂纹的产生取决于成形过程温度场与应力场的分布特征.用有限元法对预热和水冷两种温控方案进行了模拟仿真,对比分析可知,较预热成形,水冷成形零件表面质量良好、热裂倾向低.随后依水冷条件按跳跃路径计算了叶轮成形过程的热应力场.结果表明,该方案所得零件的温度场较均匀,热应力和热裂倾向显著降低,工艺合理,有利提高成形性.     

MILLING PERFORMANCE OF COATED INSERTS WITH VARIABLE COATING THICKNESS ON THEIR RAKE AND FLANK

During the Physical Vapour Deposition of coatings, the orientation of cemented carbides insert surfaces to the plasma flux direction affects the occurring film thickness distribution on the rake and flank, which in turn might influence the wear propagation in cutting processes. In the present paper the cutting performance in milling of PVD coated cemented carbides inserts with variable film thickness on the rake and flank is introduced and with the aid of FEM-supported calculations explained. The investigation results revealed that a thicker film on the tool rake in comparison to the existing one on the flank and moreover a thick and uniformly deposited film in the cutting wedge region significantly enhances the cutting performance in milling.     

铸铁中微量元素分布规律的异化及应用

Pb、As、Sn等微量元素在不同形态的石墨区域中有不同的分布规律；在A型石墨区偏聚在基体中，在D型石墨区偏聚在石墨上。利用这两种分布规律，制取含Pb、As、Sn D型石墨铸铁，使Pb、As、Sn主要聚集在石墨上，微量残留在基体中，可以获得良好的力学性能。     

晶化对等离子喷涂Ni基涂层硬度的影响

采用大气等离子喷涂在低碳钢基底上制备了含有89．2％非晶的NiCrBSi涂层。应用X射线衍射分析和Weibull分布研究了两个晶化温度523℃和628℃下热处理2～6h对涂层微观结构和显维硬度的影响。结果表明，在两个温度下，晶化析出相晶粒大小和涂层的显微硬度Weibull模数都随着热处理时间的延长而增大，涂层均匀性变好。在523℃热处理，随着热处理时间延长，涂层显微硬度增大，在4h时达到最大值，而后下降；628℃热处理，显微硬度在2h时达最大值，而后随热处理时间延长而下降。523℃热处理4h，涂层具有最高显微硬度。     

基于FastICA去噪和改进HHT的转子不平衡故障特征提取方法研究

针对转子不平衡振动信号非平稳性并伴随较强环境噪声的特点，提出一种基于快速独立分量分析（FastICA）和改进希尔伯特-黄变换相结合的故障特征提取方法。该方法采用FastICA法去除环境噪声等因素对于故障特征提取精度的影响，再利用自适应白噪声总体平均模态分解方法将故障信号分解为一系列固有模态函数（IMF），并采用基于相似性评估的虚假IMF选择算法将与故障信息无关的虚假IMF分量剔除，从而保证故障信息提取的准确性和有效性。通过仿真分析证明了所提方法的有效性，并且实际试验表明：该方法可有效提取转子不平衡信号的故障特征，为该类故障的诊断提供了一种切实可行的方法。     

Effect of ultrasonic stirring on temperature distribution and grain refinement in Al- 1.65%Si alloy melt

A series of experiments were conducted for Al-1.65%Si （mass fraction） alloy melt to study the formation of grain refining structure with ultrasonic stirring. The cooling curves of ingots with ultrasonic were measured and compared with those without ultrasonic. At the same time, the effect of the time of ultrasonic stirring on solidification structure of ingots was investigated. The influence of ultrasonic on the grain-refining efficiency of ingots was analyzed. In order to well understand the melts behavior under ultrasonic, by using ammonium chloride solution, the simulation experiment was carried out and the temperature distribution in ingot with or without ultrasonic was compared. The results indicate that the ultrasonic reduces the temperature inhomogeneity of melt, i.e. the ultrasonic helps to homogenize the melt temperature. The effect of stirring and heat generation in ingot start to occur with increasing the time of ultrasonic stirring.     

焊接电弧的等离子流力

以试验为基础，分析了直流ＴＩＧ电弧阳极热斑表面等离子流力的径向分布，数学表达式，电弧长度及电流的影响，阐述了该力在整个电弧机械作用力中的地位。     

电除尘器气流分布技术研究进展

气流分布状态是影响电除尘器收尘效率的关键因素之一.本文介绍了电除尘器气流分布技术的研究和应用现状,并指出了其发展方向.