Advanced Materials Research Vols. 482-484

Abstract: The tensile behavior of friction stir joints containing root flaw in A6061-T6 aluminum alloys was investigated. First, plates of this material were butt-jointed by friction stir welding, and the metallographic observation and micro-hardness analysis were made on the cross-section of the weld. Then, tensile tests were performed in MTS 810 testing machine, and a digital CCD camera was used to monitor the process during testing.. Finally, the tensile fracture surface analysis was examined by scanning electron microscopy (SEM). The results show that the root flaw has no apparent effect on the tensile properties. However, it was observed that a crack about 0.3 mm in length occurred in the root part of the weld center in the early stage of tensile test, and the crack did not further propagate during the sequent tensile experiment. The tensile specimens were all fractured in the heat-affected zone (HAZ) of the retreating side, which is the area coincident with the region of maximum local strain and lowest hardness.

Abstract: The industrial manipulator has been introduced. The manipulator of cylindrical coordinate type provides with three degrees of freedom including rotation, lifting and expansion, which has corresponding rotation structure, lifting structure, expansion structure. All parts are drove and controlled by using hydraulic cylinder. FluidSIM-H is hydraulic simulation software and tightly integrated the CAD function and simulation function. To simulate and analyze the operation of hydraulic circuit which based on the physical model of hydraulic element and LOGO control. The results showed that the industrial manipulator can work reliably.

Abstract: It is a good way that the fluidized bed is used as a substitute for reduction shaft in Corex process. Which can reduce energy consumption, environmental pollution and construction costs further, and also improve the competitiveness of Corex and blast furnace. At present, the sticking problem is present in iron ore reduction process and interrupts the reduction process, it has become a major obstacle on the development of fluidized bed. In this paper, a visualization hot model of fluidized bed is introduced. The influence factors on sticking behavior were analyzed from reduction temperature, gas velocity, atmosphere, degree of metallization or reduction and property of iron ore, the research provided a strong theoretical basis for controlling the sticking.

Abstract: Vibrating sieve is a special kind of equipment which used to grading materials according to particle granularity. By the vibration acted on the sieve, the materials are loosed, are divided into layers, are transported and are permeated the sieve to screen the materials. Discrete Element Method (DEM) has been an effective numerical method to research the granule system motion. Using Particle Flow Code (PFC) based DEM, the screening process, the particle group motions on the screen, are simulated. How the amplitude, the frequency of vibration, the vibration direction angle, the decline degree of sieve effect screening efficiency are presented.

Abstract: In order to study the influence of large size aggregate on self-compacting rock-filled concrete, the compactness between self-compacting concrete (SCC) and rocks, as well as the whole workability of self-compacting rock-filled concrete, the experimental test in the present paper was carried out on the 500-ton electro-hydraulic serve testing machine and the sizes of specimens are 450mm×450mm×450mm and 450mm×450mm×900mm. The results show that the exterior damage of self-compacting rock-filled concrete specimens are different from that of standard concrete specimens; the damage sections are flat and rocks are cut through in some areas, which shows mainly bond failure at interfaces between self-compacting concrete (SCC) and rocks. The compactness inside is well and the strength of self-compacting rock-filled concrete can almost reach that of SCC, which provides theoretical basis for the application of self-compacting rock-filled concrete.

Abstract: The asphalt foaming is a nonlinear kinetics process under high temperature and high pressure with multi-phase medium and multi-field condition. It includes stages like transient contact, heat exchange, phase change and bubble generating process. In order to quantitatively describe the relationship between the asphalt foamability and the asphalt foaming equipment physical parameters, the engineering method for asphalt foaming modeling integrating gas-liquid phase change process is created. Meanwhile, the asphalt foaming dynamic model for design parameters and coupled field distribution, which can express multiphase contact, heat exchange and further phase change, is built. Compared to the old non-phase change model, the new model has a stronger correlation to the asphalt foaming experimental results. Therefore, the study is significant for the redesign of the asphalt foaming equipment.

Abstract: The need for fiber modification was described, and the principles about how the reagents act on the fibers was also shown, then a series of orthogonal experiments was designed, at last a comprehensive analysis and pictures about the surface of the fibers before treatment and after treatment from the microscope was finished, at last get the conclusion 50g/L friction-up reagent and 3% weight gain reagent is the best solution.

Abstract: It is very important that apply manipulator to transit material in certain high-temperature, multi-dust dangerous environment. Design a kind of manipulator which used PLC as main controller. Use this manipulator to replace manpower transiting material. It discourses in detail the composition of the control system and the software realization method. Practice shows that the application of manipulator not only reduced the labor intensity of the worker also significantly increased productivity.

Abstract: Microstructure evolution of Mg-5Gd-2Y-2Zn-0.5Zr alloy during high temperature heat-treatment at 500°C in the time range 10-70h was investigated. The results show that after adding the element Y, the as-cast Mg-5Gd-2Y-2Zn-0.5Zr alloy forms the Mg12Zn(Y,Gd) phase with 18R-LPSO structure at the grain boundary. During heat-treatment at 500°C, the stability of 18R-LPSO structure is weakened by Gd atoms, parts of LPSO phases dissolve gradually into the matrix with time prolonged and a new type Mg(Y,Gd)Zn phase come into being. LPSO phase in the grain boundary can ensure the ultimate tensile strength and elongation of the alloy, and effect of dissevering on the LPSO phase by Mg(Gd,Y)Zn phase results the decrease of UTS and elongation.

Abstract: Dichloromethane (DCM) is a toxic pollutant with prolonged persistence in air and water. The work focused on the cultivation of Methylobacterium rhodesiaum H13 which could utilize DCM as the sole carbon source. By comparison and analysis, R2A was chosen as the suitable culture medium for large-scale cultivation. Furthermore, the optimized composition of medium was established on the basis of biomass obtained and the DCM degradation activity of M. rhodesiaum H13, which contained yeast extract 1.5 g/L, peptone 1.5 g/L, glucose 1.5 g/L, sodium pyruvate 0.9 g/L, K2HPO4 0.9 g/L and MgSO4•H2O 0.15 g/L.