Study On Low Pressure Casting Of ZL205A Alloy Used In Large Unitary Hull And Typical Disfigurement

Because of its excellent mechanical properties, the shelly casting of ZL205A alloys meet the need of light weight, low cost and develop rapidly in space and aviation. This study mainly analyzes the shelly casting of ZL205A. Its bad foundry capability leads to the instability of inside quality of the shelly casting. Because of shrinkage, cavity and cracked segregation, the castings scraped seriously, the rate of eligible cast was only about 20%. The serious problems of inside quality did not only cause great economical losses, but also became the bottleneck of manufacturing. The designing, low pressure parameter of cast processing and the casting quality control of shelly ZL205A alloys were also studied in this paper.At the same time it was studied about the reason and prevention of shrinkage, cavity, cracked segregation and the influence of mechanical properties. Several measurements were performed to reduce the shrinkage, cavity, including increase the number of gating and adjusting the low pressure parameter and add the round and design the technical patch. Through reinforcing the mix and shortening the time of silencing of alloy and adjusting the gating parameter, crack and segregation were avoided evidently. The influence of different levels of dispersible shrinkage and point segregation on mechanical properties was obtained through the study of mechanical properties of different level disfigurement. The average tensile strengthσb, yield strengthσ0.2 and elongationδ5 were all dropped and they influenced elongation greater than tensile and yield strength. The mechanical properties of ZL205A were not influenced very much by the point segregation.