Numerical Simulation Studies On Casting Process And Effects Of Process Parameters For Horizontal Centrifugal Compound Casting Rolls

Centrifugal compound casting is one simple method to make double layer or multilayer composite casting. And the method has been widely applied to made composite roll, composite pipe casting. In the double or multilayer layer compound roll production industry, due to the material of inner and outer layers is different, the key to the technology is how to control the interface bonding quality of heterogeneous metals during the process of duble and multilayer compound casting. On the one hand it will be very high cost and waste resources using trial and error method to determine the process parameters, on the other hand it requires a lot of basic work to develop special software then extension and application of the sofrware is limited. In this paperjfinite element models of horizontal centrifugal compound casting would be established based on general finite element analysis commercial software ProCAST. Then the simulation model provides a general, simple technology to simulate flow field, temperature field and stress field of horizontal centrifugal compound casting process, optimize of centrifugal casting process and improve the quality of the roll.Horizaontal centrifugal casting is an important stage in roll production, but there is serious distortion during simulation of horizontal centrifugal casting process in Procast software. To solve this problem, stages modeling method is proposed in this paper to simulate the horizontal centrifugal casting process by using ProCAST software. In this model according to force analysis of the liquid under centrifugal casting process, horizontal centrifugal casting of cylindrical parts was divided into gravity flow(before the metallic melt contacts the revolution mold, the flow behavior of the metallic melt is gravity-casting process) and centrifugal flow(after the metallic melt contacts the revolution mold, the metallic melt moves with the revolution mold; the flow behavior of the metallic melt then changes to centrifugal casting). Filling process of cylindrical part during horizontal centrifugal casting was simulated using stages modeling method, and this model was verified using the existing hydraulic test, the results show that the method can realize the cylindrical horizontal centrifugal flow simulation.Using stages modeling method flow field and temperature field of typical cylindrical parts(wet-type cylinder liner shorthand for WTCL) horizontal centrifugal casting process are simulated, temperature field which were well in agreement with that of the practical production is obtained, and then the validity and rationality of the model in horizontal centrifugal casting filling and solidification process simulation is further testified. The factors that affect the depth of the defect were analyzed, the question that large casting defect and high rejection rate of WTCL during horizontal centrifugal casting was solve.An finite element to simulate compound casting process of roll using ProCAST software is proposed, on the basis of horizontal centrifugal casting simulation. The development of mold filling, solidification of melt and evolution of temperature field in Cr4 compound roll and the temperature field in the mold outside of roll were computed with the model. Temperature history on the surface of the mold and the microstructure of the CR4 layer on corresponding position were measured. comparing the simulation results and the experimental results, simulated and experimental results agree well.Stress field model of roll compound casting process is established using ProCAST software, on basis of mechanical properties of Cr4 material and intermediate layer material were measured, and carried on the stress field simulation. Then the stress field during compound casting solidification process and the residual stress field of cast rolll is obtained. A comparison between simulation and measurement of roller surface layer stress were made, simulation results are identical distribution with the measured results.According to bonding quality analyzed of the interface between roller outer layer and intermediate layer, the criterion of if the metallurgical bonding is complete and the minimum thickness of bonding layer is given. The influence of compound cast parameters to the centrifugal time of outer layer on fully combine and effective thickness of outer layer were studied. The major-minor sequence among factors on effective thickness of outer layer was decided, and which was the intermediate layer pouring temperature> inner surface heat transfer coefficient> thickness of intermediate layer> thickness of coating> end cup sand materials. To eliminate roll shaft neck shrinkage, and the influence of process parameters such as the wall thickness, material and length of chiller, and the sand materials in lower box on shrinkage cavity size and location were studied. Design the reasonable processing technology, which can completely eliminate shrinkage cavity in the lower roll chsft neck.