Papers by Author: Jian Mei Wang

Abstract: The FEM model of lubricating oil film was built with mill oil-film bearing as the research target, the analysis system of magnetic-fluid lubricating oil film for oil-film bearing was developed. APDL and CEL languages were applied to compile the inner analytical programs, and the combination of VB, ANSYS Mechanical with ANSYS CFX was perfectly realized. Through the numerical simulation of magnetic-fluid lubricating film, the load-carrying performances of oil-film bearing with magnetic-fluid lubrication were analyzed, and the relationship among magnetic field intensity with oil-film pressure and temperature was quantitatively calculated. The numerical results have shown that the magnetic-fluid lubrication has obvious influences on oil-film pressure when magnetic field was applied on oil-film bearing, the lubricating viscosity increases with the magnetic-fluid intensity, and the oil-film pressure and temperature also increase with magnetic-field intensity. However, the increasing increment of oil-film temperature is far lower than that of oil-film pressure. The above conclusions prove that magnetic fluid with proper magnetic field can effectively improve the load-carrying capacity of lubricating oil film and enhances the stability of oil-film pressure. Moreover, the adjustable intelligent oil-film pressure with magnetic field is deduced to be feasible.

Abstract: Based on experimental results and theoretical analysis at different temperatures and time of unit diffusion quantity，the chemical reaction rate in the reaction process between iron and molten tin, is investigated within the range of 260～350°C. The results indicate that the chemical reaction rate at different time decreases rapidly with the time at the same temperature, it take about four minutes to cease. Morever, the numerical value of the reaction rate at different time are close and decrease with the increasing of the temperature.

Abstract: The accuracy of the max shear force of rolling shear is of vital importance to the proper selection of motor power and the optimization design of structure strength. The test on shear force during the shearing process of stainless steel was done on 3000 mm cut-to-length rolling shear of some Large-scale Iron & Steel Co., Ltd. The test results have shown that the weight of upper-blade carrier can bring about the fluctuation of measuring signals of shearing force at the start and end instants. Meanwhile, the shear force during the shearing process will gradually increase with the increment relative cut-in depth, and the process from the bite-in of upper blade into steel plate to the fracture of steel plate is very short, thus the link force on the side of firstly-fallen-off blade will initially increase and then will decrease by large increment amplitude. The shear force at the cut-in stage will dramatically increase. During the cut-in stage, the shear force is basically a constant due to the constant shear angle. In summary, the above test results have important referential value to the calculation of shear force and the design of structure strength.

Abstract: The evolvement of plate in 15-roller combination leveler has been studied in this paper using both geometrical analysis and FEM. The results show that the bending deformation and curvature evolvement are different from those obtained by general leveler. The technologies of parallel leveling and tension leveling are adaptive to the roll system of combination leveler, which not only can improve leveling precision, but also can erase the influence of negative torque on leveling roll, thus improving the leveling strength capacity of leveling materials. Meanwhile, a new calculating method of leveling process was pointed out, whose results were basically consistent to those of experimental results.

Abstract: In this paper, the diffusion quantity of different temperatures and unit time have been investigated basing on experimental results and theoretical analysis. The diffusing parameters of molten tin in the reaction process is investigated according to diffusing formula. The results within the range of 260～350°C indicates that the diffusing activation energy is increased with the time until the reaction ceases and it is decreased with the increasing of the temperature and substrate vacancy, but the average diffusing constant of tin increased with the temperature.

Abstract: To prolong the service life of large-scale journal bearings, the major factors that have influences on bearing performances should be taken into account. By consideration of the variations of viscosity and density with pressure and temperature, a more thorough thermo-hydrodynamic lubrication model was established. With designation of variables with nondimensional parameters, a series of equations were nondimensionied, and the corresponding energy equations at different oil-film layers and boundaries were obtained respectively according to proper difference formats, and then solved by the integration of Finite Difference Method (FDM) with Boundary Element Method (BEM). Calculation results have proved that such complete mathematical model could provide great theoretical guide meaning to improve the lubrication performances and to prolong the service life of contact components of heavy journal bearings.

Abstract: Tension reducing is one of the important processes in the production of steel tube, especially for the production of small diameter and thin-walled tube. Tension reducing mill has wide work speed range. A series of finished tube with different diameters and wall thickness were produced from a pierced billet by changing the velocity ratio between the rack. It is important to obtain the relationship of the wall thickness variation and tension for the production of satisfied steel tube. A speed calculation model was established for a suitable tension. The setting of the initial velocity field has great effects on the convergence of iteration process or iterations, so it must strictly satisfy the velocity boundary conditions, and must not break continuity condition and approximately meet the constancy of volume.

Abstract: The heat deformation failure form of workroll bearing chock in Bao Shan steel 2050mm hot strip mill was studied by using finite element method. This phenomenon indicates that the internal friction heat in the bearing is the major heat source that results in temperature rise. With the establishment of reasonable temperature boundary conditions on free and contact surfaces, the heat conduction model of bearing chock was built and discreted. By means of finite element method and three dimensional FEM program, the rules of temperature distribution and heat stress distribution of bearing chock were discussed. Moreover, some suggestions on bearing improvement were brought up.

Abstract: A new coupling numerical algorithm has been developed to integrate Finite Difference Method (FDM) with Boundary Element Method (BEM) to analyze shear performance of oil film by iteratively solving a series of equations such as the film flow velocity and shear stress equations for contact bodies in bearing system. With consideration of the variations of viscosity and density with pressure and temperature, the effects of shear stress of oil film layers on lubrication performance of contact surfaces under different loadcases were discussed. Moreover, Germany-made Anton Paar MRD (Magnetic Rheologic Device) was used to determine the relationship between the viscosity and shear stress of lubricating oil. The conclusions were verified to be beneficial to the further study on lubricating performance of heavy contact components and to prolong their service lives.

Abstract: To internal magnetic abrasive particles surface finishing, the motion of magnetic abrasive particles was influenced not only by the intensity of magnetic induction, but also by the internal diameter, and the magnetic inductive capacity was also an important factor that influences finishing quality. In this paper, under the same experimental conditions, electromagnetic field and permanent magnetic field were respectively used to magnetic abrasive particles surface finishing on thin stainless steel bush and 45 steel bush, new thoughts on inserted permanent magnetic pole and butted permanent magnetic pole were pointed out. The finishing quality of two kinds of work pieces under three different magnetic poles was compared. The results have shown that permanent magnetic pole could decrease the surface roughness Ra of work piece from 1.6μm to 0.2μm, which could solve the puzzles encountered in internal magnetic abrasive particles surface finishing on magnetic inductive work piece and had good promising application value.