Advanced Materials Research Vols. 154-155

Abstract: In this paper, numerical simulation technique was used to simulate the potential distribution when the X70 steel was influenced by stray current of different strength. The simulation results suggested that without cathodic protection, X70 steel was obviously anodic polarized in the current-out zone, with the potentials of -636mV, -559mV and -500mV respectively when the stray current was 15mA, 50mA and 100mA. The anodic polarization degree increased with the increasing of stray current density. The potential of the current-out zone was about -1000mV, -870mV and -780mV respectively when cathodic protection was adopted, and X70 steel was fully protected as the stray current corrosion controlled. The accuracy of simulation was proved by comparison simulation results with practical measurement results, which showed that the numerical simulation technique was an efficient, quick and convenient means for stray current corrosion study.

Abstract: A novel segregative carbide was discovered during the manufacture of high speed steel roll. The carbide with rectangular shape is a type of MC carbide not yet reported in the open literature. It is a face centered cubic carbide with a lattice parameter a=0.414445 nm, very close to the VC carbide but with a different chemical composition. The M represents the metallic elements (at.%): 91.80 V, 3.17 Cr, 2.19 Fe and 2.83 Mo.

Abstract: As the heart of the aircraft, aircraft engine is the decisive factors of aircraft performance. The turbofan engine technology is in the forward position of aero engine, and has become the main power of fighter and civil aircraft. In order to improve the processing efficiency of the aero engine fan blades, a high-efficiency and energy-saving technology was given to replace the traditional processing methods. The paper analyzed and researched the problems which appeared in the machining process of the aero-engine, and the high-efficiency and energy-saving methods was summarized which would become the technical guidance of high efficiency machining of the aero engine fan blades.

Abstract: The guiding forces will affect the stability of the ring rolling process and the quality of the product directly. In this paper, the guiding forces and the sector gear forces are analyzed by building theoretical equations and numerical value simulations. The variation tendencies of the guiding forces and the sector gear forces changing with the ring’s outer diameter in both steady and unsteady ring rolling phases are found out base on the theoretical and simulation analyses.

Abstract: The vacuum degree characteristics of venturi tube mixer are researched, and the factors affect the mixer vacuum degree and air-fuel ratio are analyzed. A new mixer is developed with the structural characteristics are the double channel and respectively control. The bench test and actual road test of the matching performance between the new designed mixer and LPG engine are conducted, and the test results show that the integrated matching performance is good, and possess the advantages of simple structure, convenient operation, reliable control. The mixer can control the air-fuel ratio simple and reasonable, so as to achieve good economy and emission performance under the premise of the LPG engine has adequate dynamic property, which according with the state development strategy of promoting low carbon economy.

Abstract: In this paper a Lab-On-Chip device using negative dielectrophoresis has been proposed for the focusing of particles at the center of the micro-channel. A 3D computational model was presented to simulate the focusing process. In particular, the model will solve for bioparticle movement and Joule heating. In the experimental study, the mixture of viable and nonviable yeast cells was used to demonstrate the focusing effect of the designed microfluidic device. The fabricated chip performs a desired focusing result for the conditions with the electric fields frequency of 1MHz, the medium conductivity of and the applied voltage , which validities the proposed 3D computational model. This Lab-On-Chip device provides a simple and effective mean of particle focusing.

Abstract: In order to develop an environmental friendly passive films on galvanized steel sheet, a chromium-free passive solution based on waterborne polyurethane (WPU) and Manganate was studied. The results show that the optimized compositions in passive solution are KMnO4 6g/L, (NH2)2CS 5g/L and WPU 150g/L. The passive films were prepared by dipping steel substrates into the passive solution for 10 seconds and drying at 120 °C for 30 seconds. SEM observation shows that the film’s thickness is about 1.5 µm. XRD patterns indicates that the chromate-free passive films mainly consisted of MnO2 and K2MnO4. Anticorrosion tests indicate that the chromate-free passive films can provide an excellent barrier to corrosive agents.

Abstract: Vibration characteristic of direct drive A/C bi-rotary milling head is been analyzed by finite element method (FEM), former four order vibration modes of the milling’s structure are given. The influence of the swing angle of the A-axis to the natural frequency of the milling head is analyzed. The natural frequencies when the milling head is working are interval values, the first order natural frequency is [120.48, 122.91], the second order natural frequency is [139.68, 142.08], the third order natural frequency is [328.68, 331.9], the fourth order natural frequency is [369.68, 372.45]. This computing provides technological support for design and improvement of this type of milling head.

Abstract: According to the actual situation of special resistance welding capp of nuclear power zirconium tubes, using nonlinear finite element analysis technology to establish an three-dimensional numerical analysis model. Analysising the distribution rules of welding residual stress and deformation. Simulation results can be explained a number of welding-related stress problems and also provide a favorable reference for optimizing the welding capp method and implementation of capp processes.

Abstract: Micromold manufacturing technology is very important for the mass production of micro parts. In this paper, modeling of micromold is established in 3D software firstly. The 3D modeling is input into machining simulation software Master CAM to simulate machining process. The machining parameters and cutting tool path are optimized in machining simulation. Machining G code of micromold obtained from post-process program of Master CAM is input into HMI system of Micro Machine Tool (MMT), and hence the micromold will be machined precisely in MMT.