Study On Investment Casting Process Of K4169 Superalloy Complex Circular Castings

At present,China's investment casting technology is gradually reducing the gap with foreign countries,However,for the whole cast of high-temperature alloy casing parts,the level is still relatively backward,the metallurgical defects,size control difficulty and short service life,It is of great significance to study the investment casting process for the casting of such casings and to further promote the use of such castings in aeroengines.Complex circular castings is an important part of the engine casing type,is made of K4169 superalloy casting forming,compared with previous research and similar castings,this part has the characteristics of overall wall thickness,the hot pot is dispersed,and a lot of blindness.Based on complex circular castings as the research object,this paper get a set of feasible investment casting process parameters,completed the development of the casting,processing and installation,Master the casting process of complex circular castings.The rapid prototyping manufacturing process and the shell manufacturing process of the complex ring are studied.Through the sintering parameters and molding parameters of the adjustment test,the use of rapid prototyping technology in a short period of time to complete the investment and the shell manufacturing.The study found that the surface quality and size of the 0.2mm-per-layer fusing mold is better than that of the 0.15 mm per-layer fusing mold commonly used for small parts.The secondary immersion in white paraffin at 100 ° C Wax can improve the surface finish of investment.The first six layers were made of shell by the alternating method of silica sol and ethyl silicate.The first four layers were made of 80-100 # corundum sand.At the relative humidity 40-60% and temperature 23 ± 2?,It is possible to create a complex shell without a ceramic core.The study found that the pouring temperature and speed and other related parameters to calculate and use the moduli calculation method of the gating system design,and then through numerical simulation technology to be amended,you can design a good gating system and used in actual production.The safety factor of the riser of the complex circular castings is between 1.2 and 1.5,which can meet the requirements of its shrinkage.according to the actual casting results of the simulation and correction,take the pouring temperature of 1480 ?,preheating temperature of 950 ?,the casting speed of 11 s process parameters,you can get a good quality metallurgical complex circular castings,the casting production cycle shortened by three months.The results show that the tensile properties at room temperature of the specimens obtained from various parts of the complex circular castings are close,tensile strength at room temperature is the highest 992 MPa,the lowest is 743 MPa.The highest yield strength is 885 MPa and the lowest is 671 MPa.However,the highest tensile strength of the single injection cast sample at 1430 ? is 1250 MPa,the lowest is 1092 MPa,the highest yield strength is 1135 MPa and the lowest is 987 MPa.rupture life of the thick parts at 650? is higher than the castings of thin-walled parts,but compared to the casting of a single sample of durable life decreased significantly.