Numerical Simulation Of YLC12 Alloy Steel Valve Body In Molding Process

In the process of oil conveying, YLC12 valve bodies are important connectors which under the bad service condition of high-pressure. In this paper, by using the numerical simulation of solidification technology, we predict the possible defects during the production of casting solidification and optimize the process in order to provide a reference for the enterprise production.According to the actual process production of YLC12 valve bodies, pouring temperature and pouring time are chosen three groups:1560℃,1600℃,1620℃ and 40s,45s,50s, respectively. The results of simulation show that the shrinkage volume is 89.9 cc when the maximum shrinkage rate is 0.992 with the temperature of 1600℃ and the pouring time of 45s that is the optimum technological parameters. To further optimize the casting process, we use insulating riser to replace the original riser, remove the bottom of the riser and add cold iron, the results show that the volume shrinkage of casting reduced to 71.61 cc. In addition, the new process scheme is optimized by changing the height and diameter of the riser. It can be find that when the riser height is 260 mm, riser diameter decreased 10%, getting the optimal Feeding Efficiency and increasing the technological yield of the casting by 6%.Besides, according to the results of simulation analysis and the structure characteristics of the casting, the casting process is redesigned. On the basis of the gating system design criteria, the sizes of the sprue, runner and ingate were redesigned. On the condition that the other processing parameters are invariant, the simulation results show that maximum shrinkage rate is 0.975 with process scenario one, and maximum shrinkage rate is 0.971 with process scheme two. By optimizing the process scheme two, maximum shrinkage rate reduced to 0.926 and the shrinkage volume reduced to 69.85 cc. Feedback to the casting production, its effect is obvious on the casting quality improvement.Finally, the change of residual stress after shakeout at the temperature of 700℃, 600℃ and 500℃ were studied. The results show that the residual stress increases with the increment of the shakeout temperature. The unpacking shakeout temperature is determined at 500℃ which having the minimum stress 307 MPa at the bottom of the riser. By choosing four points on the outside of the casting to analyze its displacement variation law, we find that the deformation of the casting in each direction is different. The statistical data of these points can be provided to enterprise for reference designs.