Effect of vibration of moulding on the gravity casted specimen during pouring of molten aluminium in metallic mould

摘要

Effect of vibration moulding has been carried out for different advanced cast products, such as die cast aluminum cylinder head, etc. Vibration moulding generally decreases the solidification time of the casting which is very important for the microstructure of cast aluminum alloys. In the present investigation, the effect of applying vibration of mould (i.e., made of cast iron) during pouring of aluminium alloy was analyzed. The mould meant for making tensile test specimen was tightly clamped on the vibration table, which vibrated with suitable frequency and amplitude.The characteristics including microstructure, hardness and tensile strength of the specimens made by with-vibration and without-vibration gravity casting processes were observed. The finer grain and denser microstructure were found in the material produced by vibration casting process compared to normal gravitation casting (with-out vibration) process. Ultimate tensile strength (UTS: 224 MPa) and elongation (3.23%) of the vibrated moulding specimens were significantly higher than the conventional gravity casting AlSi-lOMg alloy specimens (UTS: 129 MPa and elongation: 1.03%). The compared results showed significant improvements in the properties for the vibration gravity casting process.The problems in the common gravitation casting (without-vibration) normally faced are porosity, blow holes and leakage. However, these casting defects could be easily avoided by using vibration moulding at suitable frequency. Interestingly, the dense microstructure obtained from the microscopic study in the vibration casting process showed that the above mentioned problems can be eliminated easily.