Researches On Effects Of Vibrating The Chilling Path On The Solidifying Microstructure Of Alloy

Semi-solid casting is an advanced forming technology with outstanding technology superiority and remarkable economical dominance, as it can produces sophisticate-shaped complex parts with high mechanical properties and forming accuracy under rather low processing temperatures. The cooling slope casting is a branch of semi-solid casting technique, and it is also a simple and effective method to produce castings with fine globular microstructure at low cost. On the other hand, the solidification structure of castings can be refined by imposing vibration on the molten metal while in the process of solidification in certain area.A new equipment was constructed to integrate both the chilling and vibrating effect in the cooling slope casting process. Vibration with adjustable intensity and frequency can be imposed on the cooling pipe while the molten metals flow through it, in order to improve the quality of the semi-solid slurry and the microstructure of the castings.The solidification behaviors of Sn-15wt.%Pb and Al-5wt.%Cu alloys are investigated in this research using the constructed equipment. Solidification microstructures produced by traditional casting, chilling processed casting and chilling/vibrating processed casting were compared, the results show that chilling process is an effective way to refine grain while chilling/vibrating process improves the refining and spheroidizing effect further. Analysis on solidification microstructure under different pouring temperature and cooling conditions shows that: grains size can be refined by decreasing of the pouring temperature; higher mold temperature is advantageous to the forming of globular grains, in the same time leads to relatively coarse grains; the grain of the specimens solidified in the metal mold is much finer yet shows less spheroidicity, when compared with that of the specimens solidified in sand mold.In the chilling/vibrating process experiment of Sn-15wt.%Pb alloy, the intensity of vibration obviously influences solidification microstructure. Higher intensity of...