Abstract: A computer software on solid/solid reaction kinetics, KinPreSSR, is one of subsystems in the software, Intellectualized Database Management System on Kinetics of Metallurgy (IDMSKM). KinPreSSR is a Windows application developed using Visual C++ and FoxPro, and includes two main modules, “DIFFUSION” and “REACTION”. KinPreSSR deals with the kinetics on the diffusion in solid state as well as solid/solid reactions. In the ‘REACTION’ module, the system has organized the commonly recognized kinetic models, parameters and employed both numerical and graphical methods for data analyses. The proper combination between the kinetic contents and the analytical methods enables users to use KinPreSSR for the evaluation and prediction of solid/solid reactions interested. The ‘DIFFUSION’ module includes two sub-modules of “database management system (DBMS)” and "Evaluation & prediction". The “DBMS” deals with the diffusion coefficients gathered from reported documents and the data evaluated according to some rules, besides, it can provide users with retrieval of diffusion coefficients. Based on the solutions to the Fick’s first law and the Fick’s second law in the four typical critical conditions, the "Evaluation & prediction" sub-module gives the predication of concentration distribution after diffusion process in solids or computation for diffusion coefficient.
Abstract: The instantaneous speed ratio between roller and workpiece is not only the basis of the relative movement relationship but also the key to deriving the curve of non-rotating shafts with cross wedge rolling. In the paper, the instantaneous speed ratio was analyzed by using FEM. Then, the equation of instantaneous speed ratio equation was regressed by using the statistical analysis software. In the meantime, the experimental rolling equipment was designed to verify the accuracy of the regression equation. Satisfactory consistency was demonstrated by comparison of the theoretical values and results obtained from experiments.
Abstract: In the study, thermal efficiency in MIG welding of aluminum alloy with longitudinal magnetic field was analyzed, as well as softening behavior of heat-affected zone (HAZ) and base metal were investigated. The results showed that welding current decreased and resultingly total heat input reduced as the exciting current increased, meanwhile arc thermal efficiency increased and melting efficiency decreased. As a result of action of the magnetic field, the trend of grain growth of HAZ slowed down and the influence on base metal of heat input decreased. When the exciting current was 20A, microhardness of HAZ and base metal improved evidently. However, as the exciting current continued to increase, the effect of magnetic field on softening behavior did not change significantly.
Abstract: In the present research, the influences of different extrusion ratios (15, 30, 45, 60, and 75), extrusion temperatures (300 , 340 , 380 , 420 , and 460 ), and subsequent heat treatment on the mechanical properties and microstructure of as-cast ZK60 magnesium alloy have been investigated through the tensile tests and via metallographic observation. The results show that forward extrusion process can refine the microstructure of as-cast ZK60 alloy effectively. If as-cast ZK60 alloys have been extruded with the extrusion ratio 45 at 380 ,420 and 460 , respectively, and then post-heat treatment was conducted, the ZK60 alloy’s strength is higher under T5 than T6 treatment. For as-cast ZK60 alloy processed by extrusion and T5 method, the most appropriate temperature for extrusion processing is 300 , at which its tensile strength are highest provided the extrusion ratio is 30 but yet its plasticity is best provided the extrusion ratio is 45. If forward extrusions were conducted at 380 , mechanical properties of ZK60 alloy have little difference as the extrusion ratio varies. When T6 treatment was conducted for the extruded bars, their mechanical properties were improved little, moreover, the bigger the extrusion ratio is, the higher the tensile strength and elongation of the extruded bars become.
Abstract: In order to solve the problem that powder hardeners for no-bake phosphate binder sand cause powder pollution, preparation of suspended liquid hardener has been studied in this paper. Orthogonal array L9(34) was selected to arrange the experiment. Under every factor and level an experiment was done, and suspension rate after four hours of the suspended liquid hardener was taken as experimental target. Results show that the addition of suspension agent and interaction between vector and suspension agent are significant factors at significance level α = 0.05. The best scheme is the one which contents 500g powder magnesia, 500g industrial alcohol vector and 20g SN suspension agent.
Abstract: In order to increase the lifetime of oil pipelines with a length-radius ratio of 153, a special ion nitriding experiment instrument with “auxiliary anode” was designed for nitriding pipelines inside walls. The research and test results indicated that the nitriding depth and surface hardness were increased. Field tests showed that the lifetime of such treated oil pipelines increased by more than five times. This technology offered a new surface strengthening method for increasing the anticorrosive ability, wearable ability and lifetime of oil pipelines in petroleum exploitation industry.
Abstract: The semi-solid slurry of AZ91D magnesium alloy was prepared by twin-screw stirring mixer, the microstructure and mechanical properties of semi-solid formed magnesium alloy AZ91D produced by rheo-diecasting and conventional liquid die casting were investigated, respectively. The strengthen mechanism of the semi-solid formed magnesium alloy after heat treatment was analysed by EDS. The results show that the mechanical properties of semi-solid formed magnesium alloy can be enhanced markedly by T4 and T6 heat treatment, owing to decrease of the porosity and less segregation in casting, brittle eutectic compounds dissolves gradually into α-Mg matrix, and the primary phase α-Mg decomposes in the course of heat treatment. In as-cast state, the tensile strength, elongation and hardness of semi-solid formed magnesium alloy AZ91D are 222MPa, 2.3% and 74 HBS, respectively. In T4 heat treatment state, the tensile strength and elongation are increased by 13% and 210%, and in T6 heat treatment state, the tensile strength and hardness are increased by 11% and 16%. The mechanical properties of castings formed by conventional liquid die casting are deteriorated distinctly after T6 heat treatment due to its porosity and crack defects.
Abstract: At present, in the field of engineering calculation, the methods of calculation "probability" is the important analytical method. However, these are many uncertainties in the actual work; the results of analytical methods are often more serious deviation from the actual situation. With the development of computers, computing staff find out a new approach to calculation "probability" - simulation method. This method simulates the whole process of practical work through to calculate the probability. However, this method has not been verified whether or not to apply in the calculation of torpedo hit probability. To address this situation, this paper find out an acoustic homing torpedo for hit probability simulation methods, with the Matlab Simulink simulation module, and verified by example to prove that equally can be applied in the calculation of torpedo hit probability.
Abstract: Air cooling may decrease rolling efficiency in controlled rolling for needing long holding time to obtain the correct rolling temperature because of small cooling rate. The intermediate cooling can increate the cooling rate, and improve rolling efficiency. Experiment was carried out to research the effect of intermediate cooling on rolling efficiency. The influence of different cooling mode on the temperature distribution and the temperature profile characteristics of different cooling strategy are analyzed with FEM. It shows that intermediate cooling can decrease the holding time effectively, and improve rolling efficiency; the temperature homogeneity in thickness direction can be improved by opening the header one after another and cooling the plate by oscillating cooling.
Abstract: Joint grinding system is the preferred cement grinding system of current cement process design, the advantages are high productivity, low energy consumption of system and low noise, etc. It meets the industrial policy of domestic energy-saving and reduction emission, so the development prospects is broad.