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Lightweight train railway traffic has become hot research field , but as one of the components of the drive train is important lightweight hollow shaft profound . In this paper, lightweight aluminum drive train hollow shaft research project on 2024 aluminum alloy hollow shaft gear scaled pieces squeeze casting process and subsequent heat treatment system has been systematically studied . On the main squeeze casting process parameters pouring temperature , mold temperature and compacting pressure studies showed that: pouring temperature is too low, increase the freedom of solidification of the metal shell thickness , obstruct punch pressing , casting core part residual shrinkage porosity defects , low density alloys ; casting solidification temperature is too high then the extended time , grain coarsening serious, and the casting mold resistance increases . Squeeze casting mold temperature is too low feeding difficulties ; too high reduce the life of the mold , and makes Alloy bulky. With increasing pressure to suppress the grain castings can be refined to reduce the micro- porosity and other defects. When the pressing pressure is small , with the pressing pressure (≤ 120MPa) increases, the squeeze cast alloy grain finer grain size tree spacing significantly reduced, tensile strength and elongation of a larger increase . In the extrusion pressure is higher than 120MPa, the resulting casting small organization , fewer defects and internal surface of the casting without cold shuts , porosity, shrinkage , cracks and other defects. Extruded blanks for subsequent studies have shown that solution and aging heat treatment : solution treatment early , squeeze casting 2024 aluminum main alloying elements Cu, Mg mainly in the grain boundary segregation , with the solution gradually spread to the extension of time grain , and contribute to further extend the solution time uniform distribution of alloying elements . Alloy after 495 ℃, 16h after solution , alloy tissue Cu, Mg and other alloying elements dissolved in the basic matrix alloy solution treated better. The sample after solution treatment 190 ℃ aging , aging 12h alloy , the hardness reaches the peak . In the present experimental conditions, the 2024 aluminum alloy hollow shaft drive optimal squeeze casting process: pouring temperature : 730 ℃, mold temperature : 250 ℃, compacting pressure : 120MPa. At this point the tensile strength reaches 280MPa, elongation of 7.9%. Best subsequent heat treatment processes : 495 ℃, 16h after solution treatment , 190 ℃, 12h aging treatment , then reached a peak tensile alloy 435MPa, elongation of 6.9%.
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