Research On Composite Technology Of Complex Aerospace Castings

In this paper,based on the precision casting process of gypsum type,the casting coatings,transfer coatings,and soluble gypsum cores based on?-hemihydrate gypsum are studied.The purpose is to improve the surface quality of the castings as much as possible without affecting the structure of the castings.Sand removal problem.For some complex aviation castings,a composite process is formulated,which combines 3D printing sand casting,transfer coating method,and gypsum casting process,and trial-produce qualified casting products.By screening materials with beneficial effects,and formulating an orthogonal experiment with four factors and three levels,the influence of talc powder,quartz powder,mica,and sodium pyrophosphate on the process performance of casting coatings was investigated.The results of extremely poor analysis show that quartz powder and mica will reduce the leveling performance of the coating.When the content of?-hemihydrate gypsum 27%,quartz powder 3%,mica 0.6%,and talc 16%are added,good surface strength can be obtained.A coating formulation with good leveling and suspension properties.The coating can effectively improve the surface quality of AC4B aluminum alloy castings.A three-factor and three-level transfer coating orthogonal experiment was established,and it was determined that when MgSO₄ is 10%,silica sol 10%,talc 30%,alpha hemihydrate gypsum 33%,the initial setting time is 16 minutes,and the average thickness is 1.53 mm.A transfer coating formulation with high temperature crack resistance level 1.The preparation of the soluble gypsum core,with a reasonable baking process,can reduce the porosity defects of the casting and improve the surface quality.After pouring,the core will collapse and dissolve when soaked in water,which is convenient for cleaning.This paper uses gypsum as a matrix to set up a single factor experiment to study the influence of different contents of MgSO₄,BaSO₄,and chopped basalt fiber on the bending resistance,collapsibility and baking water loss rate of the gypsum core.The length of chopped basalt fiber is controlled within 1mm and mixed with gypsum slurry.When the added content reaches 0.39%,it has a significant effect on improving the impact resistance of the gypsum core and effectively improves the strength of the gypsum core;the added content of MgSO4is 20%,the gypsum core can have collapsible performance in water,solving the problem that the inner cavity of the casting cannot be cleaned.According to the structure and performance requirements of complex aerospace castings,set traditional casting process parameters,use numerical simulation technology to simulate the casting process,and predict the possible defects of the casting;apply the research content of this article to the casting,formulate a composite process,and use Anycasting software Analyze whether the composite process can improve the predicted defects;finally,the pouring experiment is carried out to verify the rationality of the various research contents in this paper,and significantly improve the quality of castings.