Applied Mechanics and Materials Vols. 275-277

Abstract: The behaviour of the surface defects on the continuous casting slab during hot rolling is investigated using the commercial FE-code LS-DYNA. The thermo-elastic-plastic material model is chosen in the simulation models, and the material implemented in the simulation is the austenitic stainless steel 304. The numerical results show the significant morphological changes of the surface defects during hot rolling and afford valuable indications for a deeper understanding of the underlying process. An accelerated crack growth and propagation are observed for the edge cracks, and the closure behaviour is found in the transverse and longitudinal cracks. The effect of temperature is significant on both the roll and the strip in hot rolling process. The developed models consider different types of mesh and element, thermal conditions, and rolling schedules. The predicted relationship between rolling conditions, the temperature distribution of crack, and the full history of temperature variation are discussed in this study.

Abstract: By the use of YH₂ and NiO, oxide particles were introduced in Ni-base ODS alloys through reactive ball milling, which shows the advantages of energy-saving and uniform distribution of the oxide dispersion. The mophological and size evolution of ball milled powder were investigated, and the synthesized oxides were characterized. The results shows that the ball milled powder exhibits the feather of severe deformation. The disintegration of particles occurs after 10 h, and the balance of powder welding and fracturing is achieved around 25 h. the formation of Y₂O₃ with the size of 20~50 nm was confirmed by XRD and TEM results.

Abstract: Through running anaerobic ammonia oxidation reactors for a few days, we found that inorganic carbon source has great influence on anaerobic ammonia oxidation reactions. The inorganic carbon source increasing, the effect of anaerobic ammonia oxidation bacteria reaction is much better and the processing rate is high. And if there are no inorganic carbon source, anaerobic ammonia oxidation reactions are running anomaly. The processing rate of nitrate nitrogen is about 80%, and the processing rate of ammonia nitrogen is only 30% or so. The anaerobic ammonia oxidation bacteria metabolic is getting worse and worse.

Abstract: Durability of the cutting tools is very complex process that is influenced by more factors. To the Identify these factors is necessary execute many experiments. The technical science defines the basic method for determining durability of the cutting tool according to results and knowledge F. W. Taylor. The Literature from renowned authors indicates that durability of the cutting tool is defined on the base of T-vc dependence. T-vc dependence like a elementary durability dependence was described according to Taylor´s graphics dependence VB=f(s) for different cutting speeds in 1906. From this theory were later derived others theories, that became the basis of theories durability of cutting wedge for the different cutting materials. For the durability identification of the cutting tool are in technical practice used two basic tests. The First is the short-term durability test and second is machining long-term test method. Both these tests have some advantages and some disadvantages that are described in Introduction of this paper. This paper describes how to create and analytically express new durability dependence for ceramic cutting tool on the base of vc-VB dependence. This dependence consists from vc - cutting speed and VB - criterion of blunting. The whole procedure and its analytical expression is the subject of this paper.

Abstract: In this study, a recycling process for stabilized secondary aluminum dross is proposed. Calcium oxide-containing materials, such as de-sulfur slag produced from steel manufacturing process, are used as stabilizing agents for secondary aluminum dross. The de-sulfur slag was first hydrolyzed. Due to the high content of calcium oxide (about 45%), hydration of de-sulfur slag can produce a solution with strong alkalinity (pH≧12). In the strong alkaline environment, the residual pernicious components in the aluminum dross, such as aluminum nitride, aluminum carbide and metal aluminum, are hydrolyzed and decomposed rapidly, resulting in the stabilization of secondary aluminum dross. The stabilized aluminum dross, therefore, was used as the raw material for preparing concrete bricks. In the subsequent concrete brick manufacturing process, the hydration reaction between stabilized aluminum dross and other raw materials can also produce strong alkaline environment (pH≧12), which further stabilizes the aluminum dross wastes, and produce high-pressure concrete bricks with satisfactory performance.

Abstract: Ball swaging is a general method in head stack assembly process to permanently attach Head Gimbal Assemblies (HGA) on the actuator arm. In this process, the swage ball is guided by a pin through the inner base plate’s hole in order to deform the base plate to tightly attach to the actuator arm. However, the loosing problem can still be found quite often in the current swaging process. This research focuses on ball sizes and the number of balls used which currently no theoretical guidance in choosing the both parameters. Besides, the best combination of the both parameters can give the best swaging performance. The three-dimensional finite element model is created and analyzed to estimate the swaging performance according to the variation of both parameters by using the tightening torque and the fixing distance of base plate to determine the quality of the ball swaging process. The results from finite element method are treated as the sampling points which are used to create the interpolation in order to increase the considered cases to cover all happening cases from both parameters. After that, a searching algorithm is implemented to determine the most suitable ball size and the number of ball used for the process. By using the finite element analysis together with the interpolation and a searching algorithm, the optimal design parameters for a complex problem with multiple conditions of consideration can be easily found.

Abstract: A type of cutting technology of manual thermite cutting technology is developed which is meet the incise requirements in especial environmental .The combustion cutting ammunition is made from cutting medicament, cartridge, nozzle. There are two synchronism courses of events to form the hole. Firstly, specimen is melted by megathermal jet stream, and then heating specimen to its burning point so that it burns with oxygen which is from jet stream and reduces melting point of specimen with alloy agent. The bright and clean hole comes into being after blowing off the slag by high-speed airflow. The paper ensured proper length of the cartridge and analyzed burning characteristics of cutting medicament by different length. The best cutting Performance be obtained While the length of cartridge is up to 90mm test on steel of Q235 which area is 2800mm2 and thick is 20mm.

Abstract: Camshaft is a key part of heavy duty diesel engine. The conventional process applies the profiling modeling grinders and universal milling machines to manufacture the cam. The weaknesses of this process include unstable cam profilogram, low accuracy, low flexibility, long product cycle and undesirable adaptability. M40 turn-milling centre and CN320 cam grinder are applied to upgrade the process. Compared with the conventional process, the improved process has evident advantages such as higher machining accuracy, surface quality and efficiency. And the compatibility with diverse product category was greatly promoted.

Abstract: This paper discussed the fabrication of cesium iodide (CsI) and nickel (Ni) tubes in the anodic aluminum oxide (AAO, Al2O3) template by dropping-drying, electroless deposition, and anodization processes. The CsI dopes with Tl as scintillator can converts incident X-ray into visible light with very high conversion efficiency of optical photons. The CsI compound is so soft and extremely hygroscopic, it is very difficult to polish to obtain a smooth and optical flat plane. However, the nano-scale flat plane can be achieved when CsI was deposited in AAO template. The ionic compound of CsI can dissolve in water to form I- and Cs+. And, I- and Cs+ can absorb on AAO to form crystalline CsI after removing or drying water. Because CsI has a good wetting adhesion with AAO CsI can easily form nanoparticles and further thin film on AAO wall.

Abstract: Shock compaction is an important industrial manufacturing technology for metal powder mixture. In order to analyze the thermodynamic response of W/Cu powder mixture during the shock compaction process, numerical simulation is conducted based on the mesoscale model. The model is generated randomly according to the real morphology distribution statistics regularity. Shock wave is achieved by introduce a rigid wall moving towards the model. Therefore, effects of deformation morphology, temperature distribution and pressure distribution under different shock velocities are presented and discussed. This work could provide a detail understanding of thermodynamic response during shock compaction process in granular-level.