喂线技术在ADI凸轮轴生产中的应用

ADI凸轮轴良好的耐磨性、强度受到铸造领域中人们的重视.为了更好地满足等温淬火球墨铸铁件生产工艺要求,以及形成从生产优质球铁凸轮轴到等温淬火的整个过程的成套技术,分别应用喂线法与冲入法生产优质球墨铸铁凸轮轴.对比结果表明用喂线法生产的球铁凸轮轴球化率、石墨球的圆整度及大小和数量都优于冲入法,结果稳定,铸件亦有很好的力学性能.并在相同等温淬火工艺和等温淬火设备下,等温淬火以后喂线法试样的力学性能优于与冲入法.     

QT700悬挂式喂线球化处理方案设计

设计了悬挂式喂线球化处理工艺流程方案及满足本方案设计要求并适应于用户实际生产需求的喂线球化处理装置,替代原有的冲入法球化生产工艺。经实际生产考核,在保证产品质量的前提下,有效地提高了QT700球墨铸铁产品的生产效率,达到了节能减排的生产设计要求。     

喂丝球化在离心球墨铸铁管生产中的应用

本文介绍了喂丝法与冲入法两种球化工艺的特点,介绍了离心球墨铸铁管生产中用喂丝法进行球化处理的有关设备、工艺、质量控制方法及结果.两种球化法对比证明:用喂丝法进行铁水的球化处理不仅大大改善作业环境,减小工人劳动强度,而且还能提高产品质量.     

一次冲入法生产球墨铸铁件

多年来,我们遵循用二次冲入法生产球墨铸铁件的规律,生产过程中常常产生球化不良现象。分析认为,主要是由于没有专用球铁浇包和第一次放出铁液数量控制不够准确造成的,同时二次冲入法也有它自身的缺点。为此,我们采用了一次冲入法生产球墨铸铁工艺,取得了满意效果。 球化处理前,把预热过的球化剂合金放在浇包底堤坝的一侧,合金上面覆盖预热后的75Si-Fe并用砂冲子捣紧,使75Si-Fe粒填入合金间隙,最后用     

洞穴式包底冲入法及炉前控制

用包底冲入法处理球墨铸铁一般的特征是铁水一盖过球化剂即开始起爆,使铁水翻动进行球化反应。因此从某种意义上说,控制球化剂与铁水作用的时间是冲入法处理球铁的关键之一,而当球化剂成分和铁水温度等主要因素大体相同时,反应时间又取决于球化剂的装载与覆盖条件。因此,改善球化剂的装载和覆盖条件对提高球化剂的吸收率、减少加入量、稳定球化都是有益的。随着对铸件质量要求的提高,特别是为了适应使用铸造焦熔炼后,铁水温度普遍提高20～     

基于全局响应面法的排气歧管流体分析优化设计

对某1.4L增压汽油发动机排气歧管进行了计算流体动力学(CFD)优化设计研究。首先采用基于有限元法的CFD求解器AcuSolve对初始排气歧管模型进行了流场分析,根据流场特征确定排气歧管外形需要重点优化设计的两个区域。然后对区域外形进行了模型参数化,创建了2个形状变量。最后调用全局响应面法以减小压降为目标进行排气歧管CFD优化,优化收敛后新设计排气歧管压降减小4.35%。研究方法对于排气歧管CFD优化设计具有一定的工程应用价值。     

冲入法球化处理稳定镁吸收率的工艺措施

冲入法是球墨铸铁生产中应用最多的球化处理方法。该方法简便易行,但因影响因素多,使工艺稳定性较差。文中总结了长期生产中的经验教训,提出了提高球化处理稳定性的工艺措施。     

喂线法生产CADI的经验探索

利用喂线法生产CADI的铸态组织,不仅可以细化石墨、保持石墨球的圆整度,同时能有效地防止球化孕育衰退,减轻组织的白口化程度。对该球铁采用合理的等温淬火工艺,将得到耐磨性好、强度和韧性更高的CADI。     

中硅钼耐热球墨铸铁的生产控制

正中硅钼球墨铸铁具有良好的高温力学性能、高温稳定性能和抗氧化性能,因而被广泛地用于发动机排气歧管的制造,已成为国际上排气歧管的首选材料。我公司长期为国外某大型发动机企业提供中硅钼耐热球墨铸铁排气歧管,在多年的生产实践中得出:通过严格的炉料选择,合理的成分控制,选择合适的球化剂、孕育剂,以及球化处理和孕育处理工艺,可以确保排气歧管本体材质合格,不出现显微缩松等缺陷。1.材料技术要求     

简易复包-夹心球化处理新工艺

我厂自从生产球铁以来,一直采用,“冲入法”球化处理工艺,这种工艺虽然有一定优点,但存在着镁光大,空气污染,镁和稀土吸收率低等缺点。我们学习了国内外的先进经验,把“冲入法”改成了简易复包一夹心球化处理工艺,克服了“冲入法”的缺点。这种新工艺,实质上是复包球化处理法与国外夹心冲人法的综合应用。简易复包是在普通铁水包中,安设一个形似小     

从过程序列、过程链到过程流

研究了产品开发设计过程集成的两项关键技术,即建立面向产品全生命周期的虚拟产品模型,以及项目模型、工作流模型和产品模型的集成问题,提出了虚拟产品模型的结构,以及项目模型、工作流模型和产品 集成框架。在此基础上,可以进一步开发出实现上述功能的软件系统。     

基于工艺过程的工序尺寸确定方法

在制定零件机械加工工艺过程中,当定位基准与设计基准不重合时,需要建立工艺尺寸链来计算工序尺寸。当零件同一方向上设计尺寸较多时,定位基准需要多次转换才能保证这些设计尺寸,其工序尺寸的确定就变得比较复杂。本文通过实例介绍一种基于工艺过程的工序尺寸的确定方法,用这种方法建立工艺尺寸链、确定工序尺寸非常实用,具有一定的推广价值。     

工艺数字化系统中的工序质量管理

工序质量管理是工艺数字化系统中的一个子系统。该子系统提供了采集器采集和手工输入两种数据输入方式，并经过一系列统计分析得到与质量特性数据有关的完整图表。该图表可帮助质量管理人员及时准确地发现加工过程中的质量问题，进而实现对工序质量控制点的管理，并通过数据库实现了与工艺数字化系统中其他子系统的集成。     

Optimal Process Tolerance Balancing Based on Process Capabilities

An optimal approach for process tolerance balancing is presented. The new approach is based on process capabilities and is to be used in the stage of process planning. A nonlinear programming model is used to simultaneously optimise process tolerances of required operations. In the optimisation model, the objective function is to minimise the total manufacturing cost with different weighting factors. Using the estimated standard deviations of the dimensions and the manufacturing cost-tolerance functions, the constraint equations for the process tolerance chains and the manufacturing capability indices are established, together with a model for the economical tolerance bounds of machine tools. A practical example was used to verify the usefulness of the proposed approach. The results of the comparative study show that the proposed approach is more advantageous in relaxing tolerance requirements and in reducing scrap rates generally, compared with the existing methods. ID="A1"Correspondance and offprint requests to: Dr Y. Gao, Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. E-mail: meygao@ust.hk     

工序尺寸、工序废品与工序能力

将工序尺寸和工序废品分为两类；对两类工序尺寸及其超差品的特征、产生原因和处理办法进行了讨论；同时对两类工序尺寸所要求的工序能力指数提出了新的见解．     

Business Process Versus Coordination Process in Organizational Change

Organizational change has been a key component in enhancing performance and organizational design. Previous process-oriented organizational change methods, however, focused on simplifying process flow without examining how it affects other organizational elements. Since an organization consists of several interdependent elements, a change within an organization can affect the other dependent organizational elements. Lack of coordination within an organization can result in unexpected poor performance and high coordination cost. In this research, we suggest a coordination theory approach to organizational process change by applying the Massachusetts Institute of Technology Process Handbook with simulation technique. For the validity test, we applied the Process Handbook to a real hospital. From the application case, we saw that the proposed approach is useful in minimizing the risk of the change project by validating change alternatives using simulation technique, coordinating the dependent organizational elements, and managing change effects on other organizational elements. In this article, we discuss the proposed method and the transformation of a new organizational design to the workflow system development.     

工艺控制：管理现代化工艺

当加工工业面对控制系统的现代化时,他们也面临着不可避免的决策机会。变化的范围从简单的元件更换到成熟的大修。     

Determining the Optimum Process Mean for a Poor Process

Wen and Mergen have presented a method of determining the optimum process mean for a poor process. Wen and Mergen balance the costs of products out-of-specification by setting the optimum process mean in the short term. However, they have not considered the quality loss for products within specification in the model. In this paper, a modified Wen and Mergen’s cost model is proposed with linear and quadratic asymmetrical quality loss of products within specification for determining the optimum process mean. Two specific conditions are considered: 1. The process standard deviation is proportional to the process mean (constant coefficient of variation). 2. The autocorrelated process. ID="A1"Correspondance and offprint requests to: Dr C.-H. Chen, Department of Industrial Management, South Taiwan University of Technology, 1 Nan-Tai Street, Yung-Kang City, Tainan 710, Taiwan. E-mail: chench@mail.stut.edu.tw     

Fuzzy Design of Process Tolerances to Maximise Process Capability

A novel formulation for designing process tolerances to maximise the process capability index is presented in this study. The proposed model simultaneously optimises the process capability of each operation, and is consolidated into a single objective fuzzy programming. A step fuzzy membership function is employed to represent the lower and upper bounds of the process capability index, the problem is then solved by finding the maximum value of the fuzzy number. This study is believed to be the first attempt to design process tolerance with the maximisation of process capability index. A comparison of the results shows that the fuzzy model is suitable for assigning tolerances to an existing process.     

强化拜耳法种分过程的研究进展

介绍了在拜耳法种分过程中,工艺参数优化、添加剂强化、活化晶种强化以及物理方法强化的作用,以及国内外对其研究的一些新成果。