Research On Investment Casting Technology Of Nickel Based Alloy Thin-walled Ring Castings

In the aerospace field,the engine is required to have a larger thrust-to-weight ratio and long-term operation stability.Therefore,a large number of sophisticated thin-walled castings with complex structures are widely used in aerospace and other fields.In this paper,the K4169 precision castings are thin-walled ring castings of casing type applied in the field of aero-engine,which are required to withstand great stress and high temperature in the working process.This kind of castings has complex structure,large size,thin wall thickness,wide wall thickness difference,and many hot nodes,which is a typical large complex thin-walled casting.Using ProCAST casting about in 1430 ?,1450 ?,1470 ? temperature,the temperature field in the process of casting,the flow field,and the casting defects were simulated.The results show that the designed pouring system,with three pouring temperatures,is able to fill stably,and the filling state is good.The setting of the gate,riser and feeding channel of the casting system is reasonable,which enables the casting body to solidify in sequence and prevents the occurrence of large area shrinkage cavity and porosity.The metallurgical defects of the outer ring lug and the interface between the struts and the inner ring of the runner were found at three temperatures.According to the simulation results and the defects in the preliminary test,the pouring temperature,the gating and riser system,and the shell insulation method were tested to compare and analyze the effects of different schemes on the casting defects,and then to obtain the reasonable casting technology scheme.The results show that when the pouring temperature is 1510 C,not only the filling requirement of the casting can be met,but also the number of related casting defects is small.Adding stiffeners to the lug and using relatively thin insulation cotton can effectively control the cracks and shrinkage defects at the lug root.Meanwhile,the results of analysis and testing of the dimensional accuracy,mechanical properties and microstructure met the requirements of products.