双半外圈调心滚子轴承外滚道磨削方法的探索

双半外圈调心滚子轴承的外滚道由两片半外圈组合而成,在用辅助工具夹两片半外圈加工滚道其精度难达到质量要求的情况下,探索了新的加工方法:用电磁无心夹具一次加工两片外圈球面滚道,在严格控制单片套圈定位基准质量的条件下,得到了比较好的加工效果。     

玛瑙山磁铁精矿氧化球团试验研究

以玛瑙山磁铁精矿为原料 ,进行了制备氧化球团的成球、焙烧和冶金性能等试验研究。试验结果表明 ,该精矿的上述各项性能优良 ,适合生产氧化球团矿。     

水泥颗粒形貌的表征及其研究方法

在众多表示颗粒形貌的特征参数中，实用球形度和圆形度可以用来表征水泥颗粒群接近球或圆的程度，并且能够方便地用现有的检测方法和仪器进行量化，比较实用球形度和圆形度的2种统计方法-图像分析仪法和人工法，前者可以在较短的时间内统计多张照片，因而统计结果更具代表性，而后者的统计结果误差相对较大，而且比较费时，但是可以统计颗粒相互粘连较为严重的扫描电镜照片。     

3D打印用金属粉末球形度分析方法

采用扫描电镜背散射电子模式对3D打印用的金属粉末进行形貌观察,并结合图像分析软件分析其球形度。结果表明:采用图像分析软件对3D打印用金属粉末图片进行识别时,扫描电镜背散射电子模式图片优于二次电子模式图片;对于粒形较差的3D打印金属粉末,可在图像分析软件对图片颗粒自动识别后,再进行手动分离,以提高金属粉末球形度分析的准确性。     

利用离心喷雾干燥制备球形粉体的工艺因素研究

研究了铝矾土料浆的离心喷雾造粒过程,考察了料浆固含量、粘度、喷雾头的旋转速度对粉体干燥的影响.从颗粒内部水分迁移的距离、空气进出口温度两方面,分析了蘑菇头颗粒、变形颗粒、球形颗粒和破裂颗粒等颗粒形貌的形成原因,并优化了一组工艺参数:喷雾头转速为12000r/min,料浆固含量为50%,热风入口温度为300℃,废气出口温度为115℃,塔内负压为-350Pa,料浆流速为4L/h,料浆的粘度为14s,在此条件下能制备出球形度高、颗粒粒径集中分布在55μm左右的粉体.     

陶瓷球研磨过程中的球形误差修正

通过建立研磨过程中单颗球的球形误差修正过程模型,对影响研磨成球过程中球形误差的因素作了分析,结果表明,采用质量较小的研磨盘有利于提高球形误差的修正能力;较低的系统固有频率和较大的阻尼可以获得较好的球形修正效果.     

Minimum centroid neighborhood for minimum zone sphericity

The minimum zone sphericity tolerance is derived from the ANSI and ISO standards for roundness and has extensive applications in the tribology of ball bearings, hip joints and other lubricated pairs. The worst-case proposed in this paper provides theoretical evidence that the minimum zone center of the two (circumscribed and inscribed reference) spheres with minimum radial separation containing the sampled spherical surface is included in a spherical neighborhood centered in the centroid of radius 2π⁻²E_C, where E_C is the sphericity error related to the centroid, which can be determined in closed form.     

中碳冷镦钢软化的发展现状和趋势

中碳冷镦钢采用球化退火工艺实现软化,其具有生产周期长、能量消耗多等特点.为了提高生产效率和线材质量、保护环境、节省能源等,中碳冷镦钢软化越来越受到紧固件厂和钢厂的重视.对此,国内外近年来开展了大量的研究工作,希望能开发出免退火或大幅度缩短退火软化时间的优质线材.评述了中碳冷镦钢软化的片改球、微细化、在线软化3种方法和软化机制,得出在线软化是今后中碳冷镦钢球化发展的必然选择.     

Estimation of sphericity by means of statistical processing for roundness of spherical parts

In the industrial standard of “balls for rolling bearings,” deviation from spherical form (sphericity) is defined as follows. It is usually determined by numerically evaluating the ball profiles, in two or three equatorial planes at 90° to each other, and recording them on a polar chart. Furthermore, the standard indicates that the minimum circumscribed circle method is relatively simple and generally satisfactory for ball profiles, and the method is also based on the assumption that two or three equatorial profiles at 90° to each other are a good indication of the deviation from spherical form. The measurement method for three-dimensional (3-D) spherical profiles is two-dimensional (2-D), because a practical (3-D) measuring system for spherical forms remains to be developed. This is another important problem. Using the method recommended in the standard, the deviation value is significantly underestimated, because the major part of the 3-D surface is not measured. Verification of the above-mentioned assumption is also difficult in general. If numerous measurements of 2-D profiles are performed, the degree of underestimation decreases. However, this requires much time and labor. In this study, a 3-D deviation value from spherical form is calculated from a few 2-D roundness values obtained using a general roundness measuring system with a statistical technique. Furthermore, an appropriate number of measuring cross sections necessary to estimate the sphericity with high reliability are presented.     

HMX晶体颗粒球形度的定量表征

采用数字光学显微镜成像技术、图像处理技术以及统计技术对HMX晶体颗粒形貌进行了定量分析,对280~400μm,400~450μm粒径范围数千个球形化处理前后的HMX颗粒球形度进行了统计计算,其颗粒平均球形因子分别为0.785和0.816及0.790和0.810,建立了HMX晶体颗粒球形度的定量表征方法,定量表征了HMX颗粒的球形化效果。