Advanced Materials Research Vols. 941-944

Abstract: Cutting temperature always highly reaches over to 1000°C when high speed machining with PCBN tools. Diffusion of tool material element may have important influence on tool wear at such high temperature, the diffusion wear and oxidation wear have become the major wear mechanism. In this paper, the rules of diffusion wear and oxidation wear for PCBN cutting tools are proposed and analyzed based on thermodynamics theory. Dissolution concentrations in typical normal workpice materials of PCBN tool material at different temperature are then calculated. Diffusion reaction rules in high temperature are developed and analyzed using Gibbs free energy criterion. The machining tests were conducted using the PCBN tools at different cutting speeds of 50, 95,100 and 180 m/min, feed of 0.1, 0.2 and depth of cut of 0.1, 0.8, 1, and 1.5 mm respectively on PUMA300LM numerically-controlled lathe. It was found that the theoretical results were uniform with the experimental data; the results will provide useful references for tool material design and selection.

Abstract: Discloses the variation of the thermal stress of the ingot heating process to cylindrical body ingot, for example, the thermal stress change in the heating process of the modeling obtained the variation of the axial, tangential and radial thermal stress,the research results provide a theoretical basis for the corresponding set of process parameters.

Abstract: This paper reports a new way to conduct fracture mechanics experiments of welded thin-walled structure for aircraft fuselage applications made of the Al 6156 ally using lock-in infrared thermography. The heat wave, generated by both the themo-mechanical coupling and intrinsic energy dissipation was detected by an infrared camera. The crack growth rate measured by the lock-in infrared thermography is found to be consistent with that measured by conventional method. It is observed that the crack can either grow underneath the stiffener or grow into the stiffener web with the crack length measured at the same time. In addition, the crack tip plastic zone was observed before the specimen was about to be destroyed.

Abstract: Hot strip cooling temperature and its cooling rate is get by strip cooling system and coiling temperature of hot rolled strip is an important parameter on its performance index. A clew regarded as the laminar cooling control system is controlled by general linear analytical model. Under detailed analysis of its control system structure, basic theory, analytical method, system design and control method, the structure of the temperature control system is characterized by feed-forward control as the main combined with feed-backward control as the assistant, the configuration software for laminar cooling process is constructed, the mathematics model is present, the characteristic of emerging fieldbus control system is analyzed, and the configuration of fieldbus is brought forward and sketch of distributed structure of laminar cooling control system in a hot rolling mill based on fieldbus and intelligent sensor is presented.

Abstract: Heat efficiency and CO emissions of Crock-type Metal Fibre Burner of Chinese Cooking Appliance were experimentally investigated. Heat efficiency with different factors was analyzed. Primary air coefficient α and port heat intensity q are the most factors. If α or q increases, heat efficiency decreases. The influence of the distance is not significant. CO increases with q increasing and CO decreases with α increasing. Under the rated load, heat efficiency reaches to 48% and CO_(α=1) is only 0.004%.

Abstract: In the present work, detailed studies were made on the transformation characteristics, microstructure and mechanical properties of heavy shell ring (HSR) in the spray cooling process. The spray cooling device of HSR was designed. The 2.25Cr1Mo0.25V steel used in production of HSR for hydrogenation reactor was selected as the testing material. The simulation of spray cooling of HSR was carried out on ABAQUS. The constitutive model and continuous cooling transformation (CCT) diagram of 2.25Cr1Mo0.25V were determined. CCT diagram, metallograph and SEM results show that the bainite forms throughout the cooling rate range from 0.5 to 10 ℃/s, and martensite begins to be produced by increasing the cooling rate higher than 60℃/s; when the cooling rate is 10 ℃/s, with the increase of the deformation degrees, the ferrite grain size becomes small, the yield strength and tensile strength increase, the elongation decrease, So it is good for refining the grain to increase the deformation. The yield strength, tensile strength and elongation were obtained under different cooling technology.

Abstract: By using the Abaqus software, FEM calculation of the quenching process of non-standard component which has complex contour has been operated, the temperature field distribution which accompanies the quenching time has been obtained. The simulation process’s precision and efficiency is excellent, this method is applicable to the quenching technics’s improvement, and can offer the calculation basis to the analysis of the thermal stress field and residual stress. It can also provide the improving scheme for the intensity design of the coal winning machinery.

Abstract: In this paper, for the rail U75V rail head spray quenching process temperature field, we founded model, meshed, loaded, and solved the finite element simulation of the process by using ABAQUS finite element analysis software, and carried on the site test using the infrared thermal imager, we received the changing discipline with time of the temperature of rail. The results of simulation are close with actual process. The precise calculation for the future in the process of quenching heat stress and residual stress laid the foundation experiment.

Abstract: In order to analyze air conditioner energy conservation of subway station quantitatively, three-dimensional numerical simulations study is conducted by using CFD theory for air distribution of subway platform, and the flow field and temperature field of the platform under different environment conditions are obtained. The orthogonal experiment method is applied to the numerical simulation analysis for human comfort under different parameters. Based on those results, the functional relationship between human comfort and the boundary conditions of the platform is produced by multiple linear regression fitting method, the order of major boundary conditions which affect human comfort is obtained. The experimental verification is also carried out, the simulation results are well coincided with experimental results. The above study provides a theoretical basis for the final energy-saving strategies.

Abstract: Based on the FE software ANSYS, the coupling temperature fields of pin-disc friction pair were simulated and analyzed in pin-disc friction rig. The results show that the temperatures of pin-disc friction pair with magnetic field are higher than that without magnetic field, under the same relative displacement, speed and normal pressure. The maximum coupling temperature increase slowly and then increase quickly with the increasing of normal pressure, under the constant magnetic field intensity and speed. The maximum coupling temperature decreases with the increase of relative speed, when the relative sliding distance and magnetic field intensity are constant.