Research On Squeeze Casting Technology For High Strength And Toughness Aluminum Alloy Parts

With the development of modern industry, strengthening-toughening and lightweight are urgent requirements for parts manufacturing, and becoming the development direction. High strength aluminum alloy has the advantages of low density, high strength and good hot workability, which can commendably meet the requirements. Squeeze casting is new process with the advantages of good forming quality, wide adaptation range and high production efficiency. It's significant for academic circles and industry circles to organically combine high strength aluminum alloy with squeeze casting.In this paper, a direct punch squeeze casting mold for bearing hook parts is designed. The mold has precise dimension, rational structure and runs stably, which can complete the squeeze casting process with different materials in different process conditions.In this paper, the form ability of ZAlCu5Mn by the direct punch squeeze casting under different process conditions was studied. The microstructure and mechanical properties of the casting, which were repeatedly prepared by casting experiment, were analyzed and compared, and then, process parameters of direct squeeze casting were optimized: specific pressure is 60MPa, mold temperature is 250~300℃, the alloy pouring temperature is 710~720℃, pressure-holding time of the punch is 15~20S. Castings with smooth surface, precise overall dimension, compact internal tissue, small grain, non-structure defect such as shrinkage cavity and porosity can be obtained. The tensile strength and elongation of the castings are 293.75MPs and 8.25% under that process condition after T4 heat treatment,which was increased by 45.2% and 6.96 times respectively. The properties of tensile strength and elongation are also superior to those obtained under conditions of resin sand casting or green sand casting, which were 276.69MPa, 4.69% and 281.94, 6.68% after T4 heat treatment.The direct squeeze casting of high strength wrought aluminum alloy was also explored and researched. The existence of oxide inclusions is the important factor of casting quality after performance and metallographic being analyzed.At the end of the paper, the characteristics, formation mechanisms and influencing factors of six extrusion casting defect during the experiment were analyzed, which included shrinkage cavity and porosity, crack, foaming, slag inclusion, cold shut and sticking, and solutions were proposed.