Advanced Materials Research Vols. 418-420

Abstract: Pure magnesium and AZ31B magnesium alloy were irradiated by a high current pulsed electron beam (HCPEB) device with pulse times 10, 15 and 20 respectively. The microstructure changes of the surface and modified layer after HCPEB treatment were investigated, and the evolution of temperature field during the electron beam modification process was numerically simulated based on experimental and theories. Numerical simulation analysis is close to experimental results and the special surface morphology arising from treatment is interpreted.

Abstract: After Fluoride, Bromide, Iodide treatment and mixture treatment on the surface of nitrile rubber, the reaction mechanism and threatment effect on the heat oil resistance of nitrile rubber are explored. Several methods are introduced to compare the modification effect, and the SEM equipment is adopted to analyze the reasons. The results show that, Fluoride, Bromide, Iodide treatment on the surface of nitrile rubber, did not significantly improve the oil resistance of the material, but mixture treatment made NBR oil resistance improved significantly. Chemical treatment, especially fluoride treatment and mixture treatment, can significantly improve the tensile strength, elongation, hardness and other physical properties.

Abstract: In order to protect the slider and disk from excessive wear, a numerical scheme is proposed for transient dynamics at slider/disk interface with the emphasis on the slider wear mechanism and the surface topology optimization of sub-ambient pressure slider. For each transient flying height and slider attitude, the modified Reynolds lubrication equation is solved by the control volume method to obtain the simultaneous pressure distribution in the slider surface. Then the dynamic flying attitude of the slider subject to the calculated pressure distribution can be solved by the Quasi-Newton iteration method at each time step. On the basis of above work, the optimization of the slider surface topology is implemented, and it’s concluded that slider crown has the most significant impact on the dynamic flying attitude and stability. Finally, a sub-ambient pressure slider is designed, which can effectively avoid the slider wear and severe fault of hard disk drive.

Abstract: Many experiments in research and development in the paint preparation involve mixture components. These are experiments with mixtures in which the experimental factors are the components of a mixture and the response variable depends on the relative proportion of each components, but not on the absolute amount of the mixture. Thus the mixture components cannot be varied independently. A common variation of the mixture experiment occurs when there are also one or more process factors that can be varied independently of each other and of the mixture ingredients, to bring about a mixture–process variable experiment. We discuss the design and analysis of these types of experiments, using flame-retardant coating formulation as an example. Goal of this paper is to encourage greater utilization of these techniques in paint preparation research and development.

Abstract: In this study, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to measure the inclusion size and identify the inclusion type respectively. The evaluated maximum nonmetallic inclusion size of bearing steel has been obtained by using statistics of extreme values (SEV). The influence of argon flow of the continuous casting process on the inclusion characteristics of bearing steels has been estimated, the influence of size and type of inclusion of bearing steel on its fatigue life have been discussed as well. It was found that most inclusions in steels are oxysulfide and alumina cluster. With the decreasing of the argon flow, the inclusion size gets larger and the amount of cluster-type inclusion also increases. In addition, by adopting the criterion of return period (T) at 200, the serial analyses show that the relation between predicted inclusion size for max and the argon flow is inverse proportion, but the fatigue life of steel is proportional to argon flow. A correlation among argon flow, inclusion size and fatigue life of bearing steel has been established in this study.

Abstract: Working fluid is commonly used in the making and using progress of cemented carbide tool. The tungsten carbide leaching of cemented carbide tool will be resulted in by the sodium carbonate in cutting fluid, because of the tungsten carbide will occur oxidative dissolution. The inhibitor that suppress tungsten carbide leaching of cemented carbide tool is investigated by soaking experiments, friction experiments, SEM analysis, and energy spectrum analysis. The test result shows that aqueous solution and sodium carbonate will cause tungsten carbide leaching through oxidative dissolution; but compound boricacidester contain benzotriazole could suppress tungsten carbide leaching. The Inhibition mechanism is that compound boricacidester contain benzotriazole could generate complete and compact protective film on the surface of cemented carbide tool, therefore, tungsten carbide leaching is inhibited. Add compound boricacidester contain benzotriazole to the water-based cutting fluid could suppress tungsten carbide leaching effectively.

Abstract: In this paper, the planning and sanding properties of Mytilaria laosensis, compared with Castanopsis hystrix, were tested. The properties were conducted according to the criteria ASTM D1666-87. The results show as follow: the planning and sanding properties of Mytilaria laosensis and Castanopsis hystrix all show excellent; in the evaluation system for full marks 5 points, the planning marks of Mytilaria laosensis and Castanopsis hystrix was separately 4.8 points and 4.7 points, and the sanding marks was separately 4.47 points and 4.3 points, so the planning and sanding properties of Mytilaria laosensis were slightly better than Castanopsis hystrix; feeding speed had remarkable influence on the planning properties of Mytilaria laosensis and Castanopsis hystrix; The wood quality had important influence on the sanding properties.

Abstract: Several different kinds of flue-gas side abrasions occurred in thermal power plant were discussed. And the occurring positions, characteristics, influence factors as well as identification and prevention methods were also introduced in detail. So some advice may serve a reference for efficiently identificating and preventing boiler failure caused by flue-gas side abrasion.

Abstract: To find out the cause for fatigue failure of a drill string used in oil field drilling, and considering the actual working conditions, axial, radial and circumferential cyclic stresses borne by the drill string in borehole of oil and gas well, fatigue strength of drill string is analyzed based on multi-axial fatigue assessment method. Then the formula to calculate the mean stress of multi-axial load of the drill string is obtained, and the formula serves as a method to calculate multi-axial fatigue life of the drill string, which has been verified through field data. It is realized that multi-axial stress has significant influence on drill string fatigue. When on drill string fatigue, Soderberg equation shall be employed to calculate the stress amplitude of drill string fatigue.

Abstract: The top of COREX-C3000 gasifier was simulated with a finite element analysis technique. It is studied of the influence of thermal expansion coefficient of the refractories on the temperature field and stress field and the function discipline with different parameters. The results of the simulation indicated that when the coefficient of thermal expansion of working lining and permanent lining are respectively 3.5×10^-6/K and 4.5×10^-6/K, the distortion and initial stress of the gasifier top are much less.