焊接接头疲劳强度改善技术在海洋工程中的应用

相对于船舶和普通海洋钢结构,深水和大型海洋工程结构面临的安全性更为重要.焊接结构很容易出现断裂问题,其中多数为疲劳失效,对于这个问题除了通过优化设计和提高质量要求之外,通过制造工艺对焊接接头疲劳强度进行改善也是很好的选择.在此结合部分海洋工程建造规范和应用实践,介绍了包括焊缝外观整体加工、焊趾打磨、TIG熔修和锤击等在...     

基于FNN智能型磨削参数决策系统

本文结合对磨削机理,模糊逻辑,神经网络的研究提出了一种基于ＦＮＮ的智能型磨削参数决策系统。在这个系统中,首先由上层专家系统决策出初始磨削参数,然后由两个ＦＮＮ单元对磨削参数进行修正。其中ＦＮＮ１利用磨削结果对磨削参数进行修正,ＦＮＮ２利用当前砂轮磨损状况对磨削参数进行修正。．     

发动机进、排气门锥形密封面的滚压加工

作为对传统工艺的改进,提出了一种针对气门锥形密封面的滚压加工方法。介绍了该工艺所采用的设备、工具及工艺参数,分析了该工艺的特点和经济效益,讨论了该工艺使用中可能出现的问题及解决方法。试验及分析表明,气门锥形密封面采用滚压工艺是一种高质量、高生产率,低成本,能提高进、排气使用寿命的新型加工方法。     

模糊综合评判在设备维修决策中的应用

根据设备的可靠性、维修性、经济性等影响因素,采用模糊综合评判,判断设备应该采用何种维修方式,并以实例验证这种决策方法的正确性。     

径向挤压的金属流动分析

以十字轴的径向挤压为例，较为详细地论述了径向挤压的流动规律，这些流动规律为径向挤压件工艺方案的制定和径向挤压件的有限元分析提供了实验依据。     

机械设计专家系统中机构类型方案的评价与决策方法

评价与决策是机械设计专家系统的重要组成部分,评价准则和决策模型是评价与决策过程中的两个核心问题.本文提出以层次分析法为核心,并在对该方法进行改进的基础上来解决机械设计中机构类型方案选择的问题.最后以某自动武器方案设计中机构类型的选择为例说明了方法的应用.     

ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY STUDY OF CORROSION INHIBITION OF MODIFIED LIGNOSULPHONATE FOR CARBON STEEL

1. IntroductionO pen circulating cooling w atersystem has been w idely used atchem icalplants in orderto utilizethe lim ited w aterm ore efficiently. H ow ever, thissystem , w ith longerrunning tim e athighertem pera-turesin the presence ofhigherdissolved…     

优势高技术金属矿产资源的策略性均衡价格及数值模拟

针对优势高技术金属矿产资源开发补偿价值体系及定价机制的扭曲,构建社会效用函数修止优势高技术金属矿产资源开发商决策效用函数,并把社会效用函数延伸到优势高技术金属矿产资源开发的斯坦克尔伯格产出决策博弈模型中。分析利他、非公平厌恶及序贯互动公平信念均衡对市场垄断程度的影响,进而分析产量与价格的变动趋势,并获得具有实验经济学意义的博弈公平均衡。通过数值模拟对博弈公平均衡进行算例验证。首次提出用生产者剩余变化来测度心理偏好产生的策略性价值的测度方法,为优势高技术金属矿产资源开发补偿价值体系完善提供技术支撑。     

固溶热处理对GH3535合金组织和性能的影响

对热轧态GH3535合金进行不同温度和时间的固溶处理,采用扫描电子显微镜(SEM)、电子背散射衍射技术(EBSD)和拉伸试验等手段研究了固溶热处理后的合金组织及其对力学性能的影响。经过1177℃,20 min固溶热处理后,合金发生再结晶与晶粒长大,一次M_6C碳化物发生部分溶解。在更高温度下(1220和1260℃)固溶热处理后,晶粒异常长大且一次M_6C碳化物数量明显减少。随着固溶温度的提高和固溶时间的延长,合金的抗拉强度随之降低,而延伸率提高。通过组织分析发现,不同固溶热处理后合金的拉伸性能的变化源于晶粒的长大和一次M_6C碳化物的溶解。     

Application of Multi－objective Optimization Method to Extracton Separtion Process

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Asymmetry of the roll gap as a factor improving work of the hydraulic gauge control in the plate rolling mill

Plate mill in the Steel Plant Cz stochowa has been recently equipped with the hydraulic gauge control system. Analysis of the work of the mill after the modernisation has shown an increase of the loads by about 20%. Additionally, changes in the geometry of the stand resulted in about 35% increase of the stress in the upper traverse of the stand and about 20% increase of the stress in the lower traverse and in the poles. These additional loads are due to the work of the hydraulic gauge control system which, on the other hand, decreases the variations of the thickness along the plate and improves the flatness of the plate.

Investigation of the possibilities of the decrease of the rolling loads is the main objective of the present project. An assumption is made that an introduction of the asymmetrical rolling may be one of the ways of solving that task. Research on the practical aspects of the implementation of the asymmetrical rolling in the plate mill Cz stochowa were carried out. The asymmetry was introduced by varying the angular velocities of the upper and lower rolls. In the present work, the theoretical analysis of that problem has been performed using the finite-element code Elroll. The code uses rigid-plastic flow formulation coupled with the numerical solution of the general heat diffusion-convection equation. It has been earlier successively applied to the simulation of the metal flow and heat transfer during rolling of the bimetalic plates. In the present project program Elroll has been used for the calculation of the loads in the symmetrical and asymmetrical rolling of steel plates. Analysis of the results obtained for the rolling of eight different carbon-manganese steels has shown that asymmetrical rolling results in a decrease of the rolling loads in the last finishing passes ranging from few to more than 70%, depending on the process parameters. It is shown that an application of the asymmetrical rolling in the stands with the hydraulic gauge control leads to: i) an improvement of the flatness of the plate, ii) a decrease of the thickness variations along the plate, iii) an improvement of the transverse profile of the plate.     

SM6000型空压机的故障分析与维护

介绍了4300mm宽厚板SM6000型空压机的结构和组成，论述了空压机常见的故障和解决方法。经过改进后，SM6000型空压机运行平稳，故障明显减少，保证了生产的顺利进行。     

Knowledge Management in Process Planning

Considerable research and development efforts have been devoted to Computer Aided Process Planning (CAPP). Nevertheless, because the CAPP problem is complex and is characterized by many interdependent technical and business parameters and variables, no viable off-the-shelf solution is yet available that can be easily or widely implemented in industry. This paper presents an overview of the CAPP field and describes a holistic component manufacturing process planning model based on an integrated approach combining technological and business considerations. The model was derived based on available literature, an overview of the state-of-the-art in Digital Manufacturing, Product Lifecycle Management (PLM) and CAPP solution providers, and a survey of Small Medium Enterprise (SME) manufacturers. This model will form the basis for developing improved decision support and knowledge management capabilities to enhance available CAPP solutions.     

Effect of Heat Treatment on Microstructure and Stress Rupture Properties of a Ni-Mo-Cr-Fe Base Corrosion-Resistant Superalloy

The influences of heat treatment and test condition on the microstructure and stress rupture properties of a Ni-Mo-Cr-Fe base corrosion-resistant superalloy have been investigated in this paper. Optical microscope and scanning electron microscope were employed for the microstructure observation, and X-ray diffraction, electron probe micro-analyzer, and transmission electron microscope were used for phase determination. It was found that the grain size increased and the volume fractions of initial M₆C carbides decreased along with the increase in solution treatment temperature. When tested at 650 °C/320 MPa, the stress rupture lives decreased with the increase in solution treatment temperature, but the stress rupture lives increased slightly at first and then decreased for the samples solution heat treated at 1220 °C when tested at 700 °C/240 MPa. The elongations showed the descendent trends under these two conditions. The stress rupture life and elongation for the aged samples all showed a noticeable improvement at 650 °C/320 MPa, but there was no noticeable improvement at 700 °C/240 MPa. The reasons can be attributed to the grain size, test conditions, and the initial and secondary carbides.     

A Porosity Test for Electrodeposits on Zinc-Base Die-Castings

A new method of determining the porosity of metal coatings on zinc-base die-castings has been developed. It uses a test solution consisting of ammonium chloride and potassium ferrocyanide. The ammonium chloride corrodes the zinc at the bottom of pores and keeps the zinc in solution; the ferrocyanide forms a white, insoluble compound with the dissolved zinc.

Irregularly shaped articles are first given a thin coat of shellac and are then completely immersed in the test solution; white spots grow on the sites of pores in the coating. For testing flat, cylindrical or conical surfaces, the solution may be applied by means of absorbent paper. The white compound shows up well on black paper; alternatively, if the compound is converted to suitably coloured salts (e.g., ferric, cupric), white paper can be used.     

The Properties of Copper Cyanide Electrolytes: A Comparison of Sodium and Potassium Formulations

The conductivity of copper cyanide electrolytes, using sodium, potassium and mixed formulations, has been measured. An all-potassium solution was found to exhibit a higher conductivity than a sodium solution of the same molarity, but the difference was relatively minor. Additions of free cyanide also had only a small effect. However, when carbonate was added there was a large improvement in the conductivity of the potassium solution, but very little for sodium. The properties of the mixed solutions were intermediate.

Anodic and cathodic polarization curves are presented for all these solutions. The results indicate that potassium formulations are generally superior for the cathodic processes, but that the opposite is true on the anodic side.

It is suggested that the optimum formulation for a commercial electrolyte may be based on an economic assessment of the various competing factors.     

68t加氢反应器电渣锭质量问题分析

炉号13ESR032加氢反应器电渣锭在电渣重熔过程中出现炉口冒黄烟,渣变黑,渣由还原性变为氧化性。通过分析电渣锭质量问题产生原因,提出解决措施并实施生产改进。改进后的电渣锭成分合格,成功交货。     

电场处理的强化晶界效应与唯象理论

以2090＋Ce铝锂合金为研究对象,重点探索了电场处理的强化晶界效应,研究了室温拉伸性能、显微组织对之的响应关系。结果表明,电场固溶处理可强化晶界,从而减弱沿晶断裂倾向,获得改善塑性的效应,但对强度影响甚微。唯象理论研究表明,电场有助于增强晶内溶质固溶能力,阻碍溶质、空位簇聚。     

Modeling of crevice solution chemistry on the initiation stage of crevice corrosion in Fe-Cr alloys

A theoretical model has been developed to evaluate transport processes and chemical reactions in crevices. The model is general in form, allowing applications to a variety of systems; even including 4 component stainless steel (e.g. alloy 316L). The model has been applied to recent experimental data and other simulated data on crevice corrosion in Fe-Cr alloys. The model considers the time evolution of the solution chemistry and electro-chemistry within crevices, and uses the method of finite elements to solve the complex set of mass-conservation equations describing the system. Activity is corrected in this model because relatively high current densities of Fe-Cr alloys cause high ionic strength in the crevice solution. The results of the model are a little different from those of Sharland model, but both simulated results are reasonable compared with the experimental results.     

AREM Shop Evaluation Method

A new tool has been developed to evaluate the reliability of assembly shop operation. It is a subsystem of AREM (Assembly Reliability Evaluation Method) [1] that can evaluate assembly fault occurrence rates by using product design information. This new tool uses approximately forty questions to assess quantitatively the influence of assembly shop operation reliability on assembly fault occurrence. This method is being used both to improve shop operation reliability and to select preferable shop, and is proven to be effective. The entire AREM system supports efficiently systematic improvement in assembly quality by examining both product design and assembly shop.