Advanced Materials Research Vol. 1088

Abstract: This paper presents the research results regarding the dependence between CTWD and penetration, bead height and bead width during GMAW cladding.

Abstract: The experiment of cutting mechanical properties of single crystal silicon surface in the micro-nanoscale is researched using nanoindenter and atomic force microscopy. The result of the experiment shows that: in the constant load, the impact of different scratching velocity for single crystal silicon surface scratch groove width and chip accumulation volume are not big; but the cutting force and friction coefficient are not increases with the scratching velocity increases; when the scratching speed is certain, the size of load has a greater impact on the cutting mechanical properties of single crystal silicon surface, with the increase of the load, the cutting force increases, but the cutting force is not linearly growth.

Abstract: According to the actual operating parameters of tundish in a steel mill, the flow pattern and temperature distribution of molten steel in tundish were studied by CFD and heat transfer calculation method. Changing the height of parapet hole, the effect of parapet hole on flow field and temperature field were simulated. The simulation results show that: the parapet hole height has large influence on flow recirculation position, which can impact surface temperature and outflow temperature of molten steel. When parapet hole height increases, the recirculation vortex moves towards the surface of molten steel in outflow zone, surface temperature rises, but outflow temperature decreases near the narrow wall. Comprehensive analysis show that, when the parapet hole height is 480mm, surface temperature is high, molten steel will not solidify at corner; the reduction of molten steel temperature is small at outflow hole.

Abstract: The flow pattern and temperature distribution of molten steel in tundish were calculated by CFD and heat transfer method. Comparing the tundish flow field and the temperature field of empty packet and turbulence inhibitor installed, the role of turbulence inhibitor in tundish was analyzed, and the advantages and disadvantages of turbulence inhibiter were illuminated. The results show that: the turbulence inhibitor can eliminate the short circuit flow at tundish bottom, stabilize flow, and homogenize molten steel composition; but the turbulence inhibitor can consume energy of molten steel, and reduce the temperature of molten steel in the tundish. Without the turbulence inhibitor, the surface minimum temperature is far from the narrow corner, it is not easy to knot cold steel; installing turbulence inhibitor can raise the molten steel temperature near inlet, steel flow will scour inlet refractory intensively, service life of which shortens.

Abstract: The temperature-heat duty (T-Q) graph method is provided to save energy for the distillation process of the mixtures with wide-boiling range. It is a visual method to find the heat sources and heat sinks, to use different utilities reasonably, and to realize the energy recovery, such as the steam generation or the heat integration. Through adjusting the operating pressures of some different column sections, the heat integration can be realized, and the multi-effect distillation flowsheet can be obtained. One case is studied and the result showed that the given method is easy and convenient for the engineers to design or to retrofit the distillation process in the interest of energy saving.

Abstract: Various types of shielding gases mixes are used for the industrial GMAW applications. The use of the direct current welding process with reverse or direct polarity influences the geometric characteristics of the beads as well as process dilution. In certain situations, such as weld deposits, the penetration should be as shallow as possible and the heat affected zone of the bead should be reduced. The paper presents the experimental procedure, the obtained results and the conclusions concerning the influence of polarity on the shape and geometry of the welding beam, while using various shielding gases and various welding parameters and by changing polarities.

Abstract: The Simpson model proposes that the rate of wood drying is directly proportional to average moisture content. In this work was done the fitting and the reproduction of drying curve for Hevea brasiliensis wood through of Simpson model and the chi-square statistical method. The curves were obtained by drying 108 specimens Hevea brasiliensis wood with size 10 mm x 20 mm x 100 mm that were drying in a laboratory kiln. The drying control was performed through gradual temperature increase in order to minimize the errors arising due the drastic loss of moisture by wood. The gravimetric method was used to evaluate the drying process, the specimens have theirs mass measured every 6 hours until the timber reached the theoretical anhydrous state. The drying curve of rubber wood obtained here can be used to estimate the drying time of this species for different kiln temperature settings.

Abstract: In this work, effects of major welding parameters, such as laser power, defocus distance of laser beam, inter-heat sources distance and welding speed, on weld geometry were investigated for pulsed Nd:YAG laser/GTAW hybrid welding of 304 stainless steel. Heat transfer efficiency of pulsed Nd:YAG laser/GTAW hybrid welding process was quantitativly analyzed based on rosenthal equation. Furthermore, melting efficiency was determined from the measured welding seams cross section area.

Abstract: In this paper we consider using multi scale modeling methods for reproduce structural and composite defects of amorphous metal alloys for quality improvement to improve process of getting information from experimental electron microscopic images. We used amorphous metal alloys with known structural defects as a studying objects. Also for this objects were generated models, which were designed for simulating real defects. For final model there was calculated the electron microscope images, which then was compared to the experimentally obtained one, after that were made conclusions about similarity of the real defect and the modeled one.

Abstract: With the development of economy, the seam tracking technology for arc welding becomes one of the major research tasks in the manufacturing area with robots. In this study, the objectives aim to develop an intelligent and cost-effective algorithm based on the laser vision sensor for image processing in Gas Metal Arc (GMA) welding. Images of welded seam were captured from the CCD camera. These images were then processed by the algorithms in the proposed image processing. To optimize the effective image process, popular algorithms in use were verified, compared and finally selected for every step in the image processing. Moreover, owing to the simple interactive environment and abundant toolboxes, MATLAB was employed to realize those algorithms, which offer a sample for engineers to achieve the goal of algorithm developed by this new but easier approach. Finally, weld seam images obtained with different welding environments were processed to enhance the proposal validity, and it’s proved to have significant effect of getting rid of the variable noises to extract the feature points and centerline for seam tracking in GMA welding and is capable for industrial application.