Advanced Materials Research Vols. 189-193

Abstract: In recent years, the hole-flanged components are not only fabricated for a thin sheet metal but they are also increasingly manufactured for a thick sheet metal especially in the automotive industry. However, most of the past researches have been studied the hole-flanging of thin sheet metal. In this study, the influences of material thickness were investigated using the finite element method (FEM) and laboratory experiments. Based on the stress distribution analysis, as the material thickness increased and the hole-flange forming ratio decreased, the effects of bending feature and the material stretching increased which resulted in the easy crack formation. The relationship between material thickness and hole-flange forming limitation was also investigated. In addition, the poor flatness on flange edge increased as the material thickness increased. The FEM simulation results showed the good agreement with the experimental results.

Abstract: Expanded graphite (EG) was prepared using fine flake graphite that could go through 50 mesh as raw material, perchloric acid as inserting agent and concentrated nitric acid as oxidant. The effects of amount of raw materials, reaction time and reaction temperature on expanded volume and sorption capacity of EG were studied, and microstructure of EG were characterized by X-ray diffraction patterns and scanning electron microscope. The results show the best process conditions are as follows: m(flake graphite):m(perchloric acid):m(concentrated nitric acid)=1:6:0.18, the reaction time is 50 min and the reaction temperature is 35°C. The reaction condition is moderate and is controlled easily. The sorption capacity of EG will increase almost linearly with increase of expanded volume. The largest expanded volume and sorption capacity of EG are 241 ml/g and 89g/g, respectively, when the expanding temperature is 800°C.

Abstract: The function of injection molding process is described in the quality, function and costs of injection products from the definition of function. Detailed analysis and evaluation are taken to investigate these three aspects, and the aspect of injection products quality is principally discussed. The analysis and evaluation of injection molding process function will be kept as the judgment of quality of the process.

Abstract: The application of the draw bead could reduce the concave/convex wall features. However, it also affected the wall thinning. Therefore, it is difficult to determine the suitable draw bead geometry to obtain a straight wall without the wall thinning. In this study, the effects of draw bead geometry of height and width on concave/convex wall feature and wall thinning were investigated by using the finite element method (FEM) and experiments. Based on the stress distribution analysis, the increasing in draw bead width and the decreasing in draw bead height lead to the concave wall feature increased; however, the application of the too small draw bead width and the too large draw bead height generated the convex wall feature. The wall thinning also decreased as the draw bead width increased as well as the draw bead height decreased. Therefore, the application of suitable draw bead height and width significantly suppressed the concave/convex wall feature and wall thinning, which resulted in the straight wall with the smallest wall thinning could be achieved.

Abstract: Ag-zeolite crystal have been obtained through immersing Na86–X (Na86[(AlO₂)₈₆(SiO₂)₁₀₆]₄₆ .2H₂O) zeolite in 0.1 M AgNO₃ solution for 12 h. Information on the interaction of Ag+ cations with framework oxygens was obtained by analyzing of IR spectra. SEM and EDS reveal that the microstructure of zeolite is tetrahedral with some little cluster between tetrahedral crystal and Ag element exists in the crystal.

Abstract: Based on the side hole and no flange and one-step drawing part forming analysis and comparison of the process, the compound die that can complete 4 procedures -blanking, drawing , punching and trimming at in the same forming-position was synchronously designed. Production testing confirmed that there were different levels of improvements in the product quality, production efficiency and economic efficiency. This paper describes die structure, die working process, design and manufacture of main pans of die.

Abstract: Numerical simulation is of great importance in sheet metal multistage deep drawing forming, optimizing mould design and improving mould research and development capability. Now researchers have proposed the numerical simulation general steps of multistage deep drawing, but there are still many problems to be resolved. This paper, comprehensively considering the two important factors of influencing the accuracy of the numerical simulation, introduces the numerical simulation simplified steps of two pass stamping forming. Results show that this new method is effective and successful in simulating two pass deep drawing forming, and the simulation results are more reasonable.

Abstract: The steering knuckle was hard to be formed because of complex shape and high quality requirement. This paper predicted fold defect in forging based on numerical simulation. The whole process was reviewed and the cause of fold and evolution was analyzed. Further more, the effect of different fillet radius as well as draft angles on fold was compared. Accordingly, the measures were presented. Finally, the process tryout was done at site. This was quite in accord with the results of simulation. As a result, the optimum analyzed technical parameters were obtained and the fold was avoided.

Abstract: Based on the application analysis of hydraulic pump CAT test-bench, an automatic testing system of hydraulic pump CAT test-bench combined with technology of measurement and control was raised, including the detailed introduction of its work principle, components and software. By this testing system, tests of hydraulic pumps were realized automatically, accurately and efficiently.

Abstract: LiFePO₄/C composite materials were synthesized by a solid-state method. The carbon source was selected from glucose, cauric acid, cinnamic acid and PVA and the influence of different carbon sources on the performances of LiFePO₄/C was investigated. The crystal structure, morphology and electrochemica1 properties of LiFePO₄/C were analyzed by XRD, SEM and galvano static charge-discharge method. The results show that the materials have olivine structure and that the LiFePO₄ material coated with carbon gives enhanced performance in terms of practical capacity and cycleability of the cell with lithium metal piece as an anode. The specimen used PVA as the carbon source has a fine and uniform particle size and shows excellent electrochemical performances. The first discharge capacity is up to 147.5 mAh•g^-1 at 0.1C rate, and after 20 times of cycling the discharge capacity is still 144.7 mAh•g^-1.