| The divided axle is mainly used in tractor.According to statistics,the occurrence rate of casting shrinkage porosity and shrinkage hole defects of the axle is as high as 70%.in the process of casting,which causes oil leakage and oil leakage of the axle shell in the process of using,and the annual economic loss is up to more than RMB 1 million.In this paper,in view of the problem of shrinkage cavity and porosity in the casting of the divided axle,based on the design of the pouring system,the simulation analysis of the filling and solidification process of the metal liquid is carried out by using the ProCAST finite element analysis software,and the optimization scheme of the casting process is put forward,which is of great practical significance to fundamentally solve the problem of shrinkage cavity and porosity in the casting of the axle and improve the quality of the axle products Promotion value.The specific research and conclusions are as follows:(1)Based on the analysis of the process property of the axle structure,three schemes of pouring system are designed.Including design process rationality of axle structure,quality control of main raw materials and auxiliary materials,process parameters,pouring position,parting surface,pouring temperature,etc.According to the theory of pouring system,the reasonable internal gate is determined to be the middle pouring type,and the minimum design value of the average static head is 246 mm.Three kinds of pouring systems with different cross-sectional area proportions,namely,closed type,semi-closed type and open type,are designed with the method of pouring speed.(2)The numerical simulation and analysis of axle filling solidification process were carried out,and the semi-closed system was obtained as the best casting system.Procast simulation software was used to simulate and analyze the mold filling and solidification process of axle in open type,semi-closed type and closed type gating systems,and the change rules of flow field and temperature field in each gating system were obtained.Easy formation on the surface of hot section on the axle parts,shrinkage cavity location near add riser,axle in internal heat section,in the isolated liquid zone setting induced cold iron,further using the simulation software Procast to enclosed gating system and semi-closed gating system for secondary simulation,simulation results show that the semi-closed pouring system can better realize the order eliminate shrinkage of solidification shrinkage of casting defects.(3)The optimized parameters of semi-closed gating process system were determined.The casting system has a total of 1 straight runner,1 cross runner,and 1 internal runner.The cross-sectional area of the inner runner is 22.5 cm2,the cross-sectional area of the transverse runner is 18 cm2,and the cross-sectional area of the direct runner is 27 cm2.The blind riser is arranged in the inner runner,the open riser is arranged on the upper surface of the bridge housing,and the cooler is arranged in the inner cavity of the bridge housing.The pouring temperature is 1580 ? and the pouring time is 10 s.(4)The air tightness test was carried out with the broken axle cast by the optimized semi-closed casting system as the test sample.The test results show that the optimized semiclosed casting system can effectively reduce the shrinkage cavity and shrinkage porosity of the semi-shaft oil seal in the axle,and the failure rate can be reduced from 70 % of the original process to about 3 %. |
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