呋喃树脂自硬砂在纺织机械铸铁件上的应用

介绍呋喃树脂自硬砂在纺织机械类铸铁件生产中的实际应用，详细阐述了原材料选取，呋喃树脂自硬砂制备工艺、造型与制芯等工序的操作要点及应用实例，分析了呋喃树脂自硬砂代替普通粘土干型砂工艺的利益所在。     

Effects of blasting parameters on removability of residual grit

This article shows the quantitative evaluation of the residual grit on a blasted substrate, and the removability of the residual grit is examined. Carbon steel plates were blasted by white alumina grit with mean diameters of 338 to 1106 μm. The velocity and the number of grit particles were measured during blasting. The residual grit was removed from a substrate surface by the dissolution of the blasted substrate surface. A mixed acid solution was used as the dissolution solution. The residual grit weight was 7 to 17 g/m². The amount of the residual grit and the penetration depth of the embedded grit increased with increasing grit size. The penetration depth was 5 to 9% of the mean diameter of the grit. The residual grit weight and the penetration depth increased with the increase of the momentum of the grit particle. This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials Park, OH, 2006.     

单颗金刚石磨粒锯切运动学分析

引进运动学中的点的速度合成定理求解单颗金刚石磨粒锯切面积和锯切厚度，通过详细的理论推导推出了单颗金刚石磨粒锯切速度方程，锯切运动方程和锯切面积和锯切厚度的计算公式，结果表明，单颗金刚石磨粒锯切面积与前一颗金刚石磨粒所夹的圆心角成正比，与进给速度成正比，与锯切深度成正比，与金刚石圆锯片的转速成反比，且依余弦规律减小。     

风淬钢渣砂在混凝土中替代黄砂的试验研究

采用炼钢副产品风淬粒化钢渣砂做为细骨料在混凝土中替代黄砂进行了试验研究。通过黄砂和风淬粒化钢渣砂在混凝土中的对比性实验,研究了风淬粒化钢渣砂对混凝土的拌合物、强度等性能的影响。从而得到适用的风淬化钢渣砂混凝土配合比。并根据风淬粒化钢渣砂不同于黄砂的特点,选择合适的水泥用量、砂率进行了不同混凝土应用方向的试验,使风碎粒化钢渣在混凝土中得到替代黄砂的作用。     

Water quality and growth of phytoplankton for the Yellow River estuary reservoirs—The nutrients release from reservoir sediments

Effects of nutrients released from sediments on eutrophication in lakes and reservoirs were not well known in China. In the test, the release conditions of nitrogen and phosphorus from the sediments were observed by batch experiment. The test results revealed that the content released is correlated to the initial content of organic matter in sediments. In the Gengjing area, when the water quality of waterway, grit chamber and reservoir were compared, the water quality of the waterway was the highest, and lowered in the order of the grit chamber and the reservoir. The grit chamber could get not only fine sand removal but also the organic substance, nitrogen, phosphorus and phytoplankton, therefore it is important to operate and maintain the grit chamber to preserve the water quality of the reservoir. Due to little organic substance in sediments, ammonium nitrogen and phosphorus weren’t released during the incubation. But from the absorptiometric turbidity unit (ATU) test results, although the release of ammonium concentration was very low, ammonium oxidizing and nitrite oxidizing bacteria existed in sediments.     

曝气沉砂池除油刮渣系统的技术改造

结合南方某城市污水处理厂曝气沉砂池除油刮渣系统的技术改造实践,介绍了一套能适应运行水位频繁、大幅波动的除油刮渣系统.该系统采用推板结构的除油刮渣板,运行时沿着导轨落入或离开水面,无需增设电机,不受桁车移动桥走偏影响,基本不需要日常维护管理.运行一年以来,该套除油刮渣系统稳定可靠、效率高、无故障.     

基于残余应力分布优选钎焊CBN磨粒出露高度

采用测量红外光谱峰值偏移的方法确定钎焊CBN磨粒内部中心轴线以及磨粒与钎料截面径向的残余应力，分析了磨粒内部残余应力的分布特征，并优化选择了钎焊砂轮工作面上CBN磨粒的出露高度。结果表明：钎焊CBN磨粒内部中心区域残余应力分布比较稳定，应力梯度小；在中心轴线两端以及截面径向外端，应力分布梯度较大，主要为拉应力，其中，钎焊CBN磨粒边缘部分的最大残余拉应力对磨粒力学性能影响最大，钎焊CBN磨粒出露高度为其自身高度的60%～70％为宜。     

钎焊金刚石薄壁小孔钻研制

以Ni-Cr合金为钎料,分别用真空加热和高频感应加热两种方式进行了金刚石磨粒与0Cr18Ni9不锈钢基体的钎焊,制作了基体外径为3 mm的薄壁小孔钻头。进行了半钢化玻璃钻削试验,用扫描电子显微镜观察钻削试验前后钻头的微观形貌。结果表明:两种钎焊工艺皆实现了金刚石磨粒的高强度连接;加热源不同及金刚石磨料出露高度差异性是影响钻头磨损方式的主要因素;为确保钻头的寿命和高效,磨粒出露高度应控制在其自身高度的50%-60%之间。     

热喷涂基体表面前处理技术的研究进展

热喷涂涂层与基体机械咬合的结合机理决定了基体表面前处理是热喷涂涂层中非常重要的处理工艺。文中概述了当前广泛应用的喷砂处理的工艺特点,指出砂粒易在基体表面镶嵌和对基体造成损伤是喷砂工艺的主要缺点,讨论了喷砂对高温合金单晶材料和超高强钢疲劳性能的影响,研究了软质基体表面超音速火焰喷涂WC涂层的免喷砂工艺。同时介绍了近年来其他热喷涂基体表面前处理方面的研究热点,包括高压水射流处理技术、机械粗化技术以及激光表面前处理,并重点阐述了其基本原理、特点及应用情况。     

基于钎料层厚度优化磨抛盘磨料粒度的仿真研究

采用热弹塑性有限元方法对钎焊金刚石磨抛盘真空钎焊过程进行建模与仿真,运用ABAQUS有限元分析软件,对其钎焊后冷却过程的瞬态温度场和应力场进行模拟,得出钎料层是影响磨抛盘钎焊后应力及变形量大小的重要因素。分析不同钎料层厚度时磨抛盘钎焊后的应力及变形量,合理确定在一定基体厚度情况下,钎料层厚度的最大值为0.2mm。结合钎料层厚度与磨粒高度的合理匹配关系,在理论上确定了钎焊金刚石磨抛盘可用的最大磨料粒度为30/35目。