索杆混合驱动并联机构的索拉力和刚度分析

分析一种索杆混合驱动并联机构的绳索拉力和刚度。考虑绳索单向受力和直线电机双向受力的特性,对机构动平台的位姿进行力学分析,得到关于绳索拉力与直线电机推力的关系式。通过规划动平台运动轨迹,得到绳索拉力与电机推力的分布曲线。结合刚度定义、机构结构参数和柔索拉力之间的关系,推导出并联机构的刚度矩阵模型;通过MATLAB仿真得到刚度评价指标,总结刚度在机构工作空间中的分布规律。     

控制棒驱动机构“Ω”环的焊接技术

1 焊接材料1.1 驱动机构“Ω”环的母材与填充材料的材质如下：这几种材料均属于奥氏体不锈钢，在固溶处理状态下使用时，一般看不到晶间腐蚀现象。但由于焊接电弧的加热，当温度达到450～850 ℃时，若钢中的w(C)超过0.02％～0.03％，且钢中的合金元素缺少Ti、Nb等能控制碳的元素时，往往就能见到晶间腐蚀现象。1.2 奥氏体钢的焊接工艺特点1.2.1 由于其导热系数小而线膨胀系数大，自由状态焊接时易于产生较大的焊接变形，为此应选择焊接热输入集中的方法，并以机械化快速焊接为好。1.2.2 由于导热系数小，在同样电流下可比结构钢时得到较…     

高速高精度印刷电路板表面贴装自动光学检测系统的研究

为满足高精密度、微型化印刷电路板表面贴装要求,实现全自动、可靠性高、速度快的贴装生产,研究了一种新的自动光学检测系统。该装置主要由光路系统、线阵摄像机、量化存储单元、模板库、专用高速图像处理单元、监视单元等模块组成,实现设备标定、缺陷识别、对中校正和位姿补偿等功能。实验证明：该检测系统可以满足高精密度印刷电路板的高速高精度贴装生产的实时检测要求,达到了较好的检测效果。     

深入开展学术交流 促进企业科技发展

文章介绍了本钢科协认真贯彻中国科协、中国金属学会的政策和精神,加强组织建设和制度建设,为学术交流提供组织保证和制度保证,以及为促进企业科技进步与发展,培养青年科技人才快速成长而采取的措施,积极组织参加中国金属学会各级学术会议、定期举办学术汇报、学术研讨、论文征评等方法和措施,为本钢的学术交流和科技发展做出了贡献。     

提高高频引弧可靠性的辅助电路法

本文分析了高频引弧的过程和高频引弧可靠性的影响因素，提出了提高高频引弧可靠性的辅助电路法，介绍了辅助电路的组成和工作原理。试验表明：这种方法简单易行，实用有效。     

An Approximate Analysis of the External Oxidation of Ternary Alloys Forming Insoluble Oxides. I: High Oxidant Pressures

The general properties of the isothermal thermodynamic phase diagrams for ternary A–B–C alloys exposed to a single oxidant at high temperatures are examined, assuming, for simplicity, the formation of insoluble p-type oxides, an ideal behavior of the alloy, and a common value of the self-diffusion coefficient for the alloy components, independent of the alloy composition, but disregarding the possibility of internal oxidation. Simplified two-dimensional phase diagrams are produced by projecting the lines and points of equilibrium of the complete three-dimensional diagrams on the base triangle, which gives the composition of the system in terms of the metal components only. Similar kinetics diagrams concerning the nature and the growth kinetics of the scales formed on ternary alloys as functions of the bulk substrate composition are also calculated for oxidant pressures above the stability of the oxides of all the alloy components and some of their general features are examined. The kinetics diagrams for ternary alloys exposed to a single oxidant contain seven regions, three of which correspond to the areas of stability of each single oxide, three to the possible mixtures of two oxides, and one to a mixture of all three oxides.     

The Internal Oxidation of Ternary Alloys. III: The Coupled Internal Oxidation of the Two Most-Reactive Components under High Oxidant Pressures

The kinetics of the simultaneous internal oxidation of the two most-reactive components B and C in ternary A–B–C alloys, where A is the most-noble and C the most-reactive component, in the presence of an external layer of the A oxide, AO, (high oxidant pressures) are examined assuming the existence of either a single or a double front of internal oxidation. For a single front a unique solution is obtained for the parabolic rate constant of internal oxidation under assigned values of all the parameters involved. When the front is double, a finite range of solutions is allowed with an upper limit equal to the single-front solution and a lower limit equal to the rate constant for the growth of external AO scales. In the case of a single front of internal oxidation, an increase of the rate constant for the growth of the external scales produces an increase of the rate constant for the internal oxidation but a decrease of the degrees of enrichment of the components being oxidized internally within the region of internal oxidation. The behavior in the case of a double front is more complex because it depends also on the actual value of the ratio between the rate constants of internal oxidation for the two fronts.     

高锰钢精密超精密镜面加工技术及试验研究

目的 利用ELID磨削技术对ZGMn13Cr2高锰钢进行精密超精密镜面磨削加工试验研究,解决其加工性能差的问题,以提升表面质量,采用二次回归通用旋转设计试验,探究不同试验因素对ZGMn13Cr2高锰钢加工表面质量的影响规律,并对各因素工艺参数进行优化。方法 对MSG-612 CNC超精密成型平面磨床进行ELID磨削工艺模块化改造后,采用240#、W10粒度的金属结合剂金刚石砂轮对直径f50 mm、厚度10 mm的样件进行ELID磨削加工,对比两种粒度砂轮的加工效果。应用二次回归通用旋转设计进行工艺试验,搭建表面粗糙度二次回归数学模型,探究不同试验因素对工件表面质量的影响程度,使用判定系数R2检验二次回归模型对实际情况的拟合程度。最后,由lingo软件对二次回归数学模型进行优化,得出ZGMn13Cr2高锰钢ELID磨削各试验因素工艺参数的最佳组合。结果 经W10金属结合剂金刚石砂轮加工后,样件获得较高精度的镜面效果,两种粒度所加工的样件表面均无烧伤。判定系数R2检验二次回归模型对实际情况的拟合度为99.24%,模型的预测结果对实际加工有指导意义。优化得出的最佳工艺参数组合为：砂轮线速度35 m/s,电解电压90 V,砂轮进给量2 μm,电解间隙0.734 mm。结论 ELID精密超精密镜面磨削加工技术可大幅提高ZGMn13Cr2高锰钢的加工效率和加工精度,减少工件表面烧伤,在高锰钢磨削加工方面具有良好的应用价值。     

采用TRC控制电源电压的恒流斩波步进电机驱动电路

介绍一种采用了恒流斩波技术的步进电机驱动电路,该电路的电源电压使用TRC(Time Ration Contr01)控制来改善步进电机的频率特性;并对其所用的恒流斩波电路及电源电压控制电路的工作原理进行了说明。     

The Internal Oxidation of Ternary Alloys. VIII: The Transition from the Internal to the External Oxidation of the Two Most-Reactive Components Under High-Oxidant Pressures

Ternary A–B–C alloys, where A is the most-noble and C the most-reactive component, exposed to oxygen pressures above the stability of the least stable oxide AO (high-oxidant pressures) may present two different types of internal oxidation, i.e. either a coupled internal oxidation of both B and C beneath an external AO scale or a single internal oxidation of C beneath an external scale of the oxide of B. This paper examines the conditions required to avoid the coupled internal oxidation of B plus C beneath external AO scales, considering both the case of formation of a single and a double front of internal oxidation. The analysis, based on an extension to ternary alloys of the criterion defined by Wagner for the transition between the internal and external oxidation of the most-reactive component of binary alloys, shows that the addition of B to binary A–C alloys is very effective in reducing the C content needed for this transition in comparison with binary A–C alloys. This results provides a basis for a possible explanation of the third-element effect. However, the actual possibility of its occurrence depends also on the ability to avoid other oxidation modes, not examined here.     

The Internal Oxidation of Ternary Alloys. V: The Transition from Internal to External Oxidation of the Most-Reactive Component under Low Oxidant Pressures

This paper examines the conditions for the transition from internal to external oxidation of the most-reactive component C of ternary A–B–C alloys by a single oxidant under gas-phase oxidant activities below the stability of the oxide of the two most-reactive components using Wagners criterion. For this, approximate relations between the solubility and diffusivity of oxygen and the composition of the binary A–B alloy matrix in the zone of internal oxidation, already developed previously, are used. The critical C content needed for the transition in ternary alloys is calculated as a function of the many parameters involved. At variance with the behavior of binary alloys, for ternary alloys this critical C content depends also on the ratio between the concentrations of A and B in the bulk alloy. The results calculated for ternary alloys are compared with those obtained for binary A–C and B–C alloys under the same values of all the relevant parameters. Finally, complete oxidation maps for ternary alloys under low oxidant pressures,including the condition for the stability of external scales of the C oxide, are also presented.     

采用卸料小车布料的粉矿仓防尘装置设计

通过对胶带输送机卸料小车的排矿漏斗以及粉矿仓的卸料孔进行改造,有效地防止粉矿仓在卸料过程中的粉尘逸出,对现场环保及清洁生产具有重要意义。