Applied Mechanics and Materials Vols. 633-634

Abstract: Aiming at the issue on grinding burn of tooth face, the temperature field formed in helical gear form grinding was analyzed. The finite element model of the single tooth of helical gear was firstly established. Considering the nonlinear relation of the physical properties of gear material to temperature, 3D finite element simulation of transient temperature field was performed by using the rectangular moving heat source model. Finally, the temperature field distribution on tooth face was achieved. The study results show that the temperature is relative low when grinding starts, then the temperature increases rapidly, and the temperature reaches the maximum value at the end of grinding; the increase of grinding depth can result in the rise of temperature when other parameters are the constants.

Abstract: The fracture samples of spring steel stabilizer bars in 60Si₂Mn were researched in this paper. Through the methods such as macro-and micro-fracture analysis, SEM fracture morphology observation, microstructure observation (surface and internal organization), and macro-hardness testing to analysis the failure causes for earlier fracture of the stabilizer bars. The results were showed that the fatigue crack source for the non-stress stabilizer bar was on the surface. The earlier fracture cause was due to the decarburized layer on the surface and the uneven organization in the internal, which lead to the fatigue resistance at the non-severe stress, was greatly decreased. And the fatigue crack of stabilizer bar in the normal stress was originated at the deformation on the surface in the processing.

Abstract: To improve the corrosion resistance of Ni-P electroless coating, the KI was added in the electroless solution. The surface micrograph was observed using scanning electron microscopy (SEM), and the corrosion resistance of Ni-P coatings in 3.5%NaCl solution was examined by polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that KI reduced the amount of defects and the size of crystal grain of Ni-P coating, and the surface of Ni-P coating became more homogenous, smoother and compact by KI. In addition, the phosphorus content of Ni-P coating was increased by KI. These factors increased the ability to corrosion protection of Ni-P coating.

Abstract: 5183 welding wire micro-alloyed using Sc, Zr, Er and automatic MIG welding system applied to weld 7A52 aluminum alloy. Optical microscope and universal tensile testing machine utilized to investigate microstructure and tensile property of welded joint, respectively. The results indicated that welded zone and fused zone was composed of uniform isometric crystal and tiny isometric dendrite crystal when the welded joint was fabricated by using 5183 welding wire micro-alloyed via rare earth element, respectively. Tensile strength and specific elongation of welded zone was improved utmostly when the 5183 welding wire micro-alloyed treatment via single Sc or Zr, respectively. Owing to mirco-alloyed treatment of 5183 welding wire by using Sc, Zr or Er, a large number of Al3Sc, Al3Zr, Al3Er granules had generated in micro-poll, which played heterogeneous nucleation role and refined microstructure of welded zone. Meanwhile, there emerged nanoscaled A13Sc, A13Zr, Al3Er strengthening phase dispersed in welded zone, which had led welded joint to exhibit exclent tensile strength.

Abstract: To achieve the effect of anti-fatigue manufacturing for hypoid gear, the author put forward a new type cold rotary forging technology, the method simplifies the die structure and adopts the local line contact continuous plastic forming. Based on the basic theory of elastic-plastic finite element method (FEM),the author uses ABAQUS to carry out numerical simulation of cold rotary forging and discuss how to build finite element geometric model and grid it in detail, and analyse the definition of workpiece material model in ABAQUS and the merger technology of Abaqus / Explicit and Abaqus / Standard. In order to measure springback error accurately, the alveolar surface shap after springback was got through the technology of surface reconstruction, it was put into Geomagic Qualify software and compare with target CAD model,then the springback error can befully assessed through comparing results.The examles proof that ABAQUS can simulate the deformation and springback process accurately, springback error of cold rotary forging can not be ignored,so springback error must be compensated.

Abstract: In this work, cutting experiments were carried out on titanium alloy Ti6Al4V by using single crystal diamond tools to investigate the effects of cutting parameters on machined surface roughness. Experimental results show machined surface roughness decreases with increases in the cutting speed within a limited range, begins to increase as the factors reaches to certain values respectively, and decreases with increases in feed rate. Cutting depth has no significant influence on the machined surface roughness. The results also show that dominant mechanisms of the single crystal diamond tools are abrasive wear and adhesion wear.

Abstract: In order to improve the acoustic attenuation performance of agricultural diesel engine exhaust muffler, take the 175 series air-cooled diesel engine as the example. Based on the original exhaust muffler structure and kept the same size of mesh partition aperture and mesh radial distribution, the four groups of different pore density schemes (14 pores/cm2,19 pores /cm2,10 pores /cm2,15 pores /cm2) are designed. The laboratory measurements are used to research the influence of different pore density exhaust muffler effect on the acoustic attenuation performance of the diesel engine. The tests indicated that the No.4 scheme did not increase the power loss, meanwhile, improved the performance of exhaust muffler noise reduction effectively, and the amount of noise elimination increased about 2~4dB(A), which provide theoretical basis for further research of performance optimization of the exhaust muffler.

Abstract: In order to realize the objective of lightweight manufacturing, the forming methods of thin-walled tubes are studied in this paper. Liquid impact forming, a compound forming technique of thin-walled tube using stamping and hydroforming processes, is presented in order to reduce the forming difficulty and increase the forming efficiency. A simple experimental tooling, including stamping device and tube hydroforming apparatus is developed. Forming experiments of stamping and liquid impact forming processes in rectangular cross-section dies are performed for 304 stainless steel tubes. The results of experiments show that the liquid impact forming technology is feasible, and it will be widely applied in the future.

Abstract: It plays an important role in guiding laser remanufacturing process and process control to research temperature field of laser remanufacturing. A numerical simulation method of temperature field based on MATLAB PDE Tool is proposed. Theoretical model of temperature field is presented. The temperature fields at different times are calculated and simulated with finite element method and MATLAB software with PDE Toolbox. The results show that this method can accurately calculate the temperature distribution of the laser remanufacturing process. The simulation results are helpful to optimize process parameters and to improve the quality of laser remanufacturing.

Abstract: In this study, recovery of high grade nickel and cadmium products from the multi metal hazardous waste was carried by pyrometallurgical and hydrometallurgical process. Semi-finished products of nickel carbonate and cadmium carbonate were firstly treated from multi metal hazardous waste. Ni-CdO system could be achieved during carbonization in medium temperature reduction. After acid leaching, Cd²⁺ could be separated from nickel. Then the high grade nickel and CdCO₃ products were obtained by smelting and precipitation respectively. The effects of the reducing agent, time, acidity, temperature were investigated. At the optimum conditions, recovery rate of nickel and cadmium is greater than 98%. This process is simple and don't require high temperature, pressure and special complex equipment.