Research On Forming And Internal Quality Of Characteristic Structural Parts Of Superalloy

In recent years,with the rapid development of my country's aerospace industry and shipbuilding industry,large-scale,light-weight,and internally complex high-temperature alloy components are being widely used.Therefore,the casting of large-scale and complex thin-walled high-temperature alloy castings has always been One of the focus of research in the manufacturing industry.This paper takes K418B superalloy as the research object,designs a scale model of characteristic structural parts based on similar theories,and uses experiments and digital simulation technology to carry out research on casting of characteristic structural parts.The purpose is to reduce the production cost and production cycle of characteristic structural parts of superalloy.To provide guidance for the forming of high-temperature alloy large-scale thin-walled actual components.In order to verify that the forming and internal quality of the scale model are similar to the characteristic structural parts of superalloy,this paper uses a combination of similar physics,numerical simulation and experiment to calculate.First,an internal step gating system and a top-injecting gating system are designed for the characteristic structure of superalloy with a diameter of 1500mm and a height of 1500mm.The filling and solidification of the characteristic structure of the superalloy is calculated by means of numerical simulation and investment casting process.According to its filling and solidification characteristics,the above two gating systems were optimized,and the optimal gating system with the slot gating system as the characteristic structure of the superalloy was finally determined.The shrinkage volume of the casting under the slot gating system was1.769 cm~3,The shrinkage porosity is 3.04%.The similarity theory calculation is used to determine the similarity criterion between the characteristic structure of the superalloy and the scale model,that is,the length scale?_L=the kinematic viscosity scale?_?=the speed scale?_v=1.The size parameters of the scale model are determined based on the length scale?_L being1,that is,the height of the scale model is changed from 1500mm to 300mm,the diameter is changed from 1500mm to 300mm,the wall thickness is unchanged 5mm,the thickness of the boss and ribs is unchanged 20mm,and the square convex The length of the table side is changed from 200mm to 40mm,the diameter of the inner circle of the flower-shaped boss is changed from 190mm to 38mm,and the distance between the ribs is changed from the original 340mm to 68mm.According to the kinematic viscosity scale?_?=1,it is concluded that the temperature field of the original superalloy characteristic structure should be consistent with the temperature field of the scale model.In order to achieve the same temperature field,by establishing a fitting equation between the pouring temperature of the scale model and the temperature field distribution of the scale model,combined with the temperature field distribution of the original superalloy characteristic structure at 1500?,the characteristics of the original superalloy In the case of similar temperature fields in the filling process of structural parts,the pouring temperature of the scale model should be 1456°C.In order to verify the reliability of the similarity criterion and the fitting equation,the correlation coefficient between the temperature field distribution of the proportional model and the temperature field distribution of the original superalloy characteristic structural parts is calculated using the CORREL function as R=0.999251371,and the correlation coefficient is close to 1,so it is guaranteed The reliability of the fitting equation and the kinematic viscosity scale?_?=1,so the simulation calculation results of the proportional model can fully reflect the forming process and internal quality of the original superalloy characteristic structural parts.Through similar theoretical calculations and fitting verification methods,it has been shown that the scale model can fully reflect the forming process and internal quality of the original high-temperature alloy characteristic structural parts.Therefore,in order to achieve the purpose of"seeing the big from the small"and shortening the production cycle and reducing costs,The forming characteristics and internal quality of the scale model at 1456?were simulated and calculated.The actual casting experiment was carried out on the scale model.The actual defect detection results show that the experimental results are highly consistent with the simulation results.It is proved that the combination of similar theories and numerical simulations and actual experiments can effectively guide the production of actual parts,especially large thin-walled castings.The production can effectively reduce its production cost,increase the yield,and reduce economic losses.