Centrifugal Casting Processing Of Tube-Shaped Parts Of In-Situ Particle Reinforced Hyper-Eutectic Al-Si Alloy Composite And Their Structure Characteristics

The main task of this paper is to research the processing of transcocrystallized Al-Si alloy by centrifugal casting. A set of vertical centrifugal casting experimental equipment which is composed of centrifugal casting machine, PLC controller, pouring equipment and lift device is designed and made in this paper. It is used to prepare trunk-like parts with gradient primary crystal particles distribution in radial direction. The experimental material is homogenous aluminum matrix composite reinforced by primary crystal particles. The experimental process is that the revolving electric engine,which is controlled by PLC controller,drives the casting mould revolve then pour metal fluid into the mould when the engine is at appropriate rotate speed and form the parts. The extraction of castings and mould matching are completed by lift device.Design three different revolution technology diagrams of centrifugal machine varying as the time. The highest rotate speed is 450r/min, 600r/min and 800r/min, separately. Total working times are 230s, 240s, 260s, separately. Input these parameters into PLC controller by instructions and make them correspond to program 1, 2 and 3, separately.To research the influence of parameters such as the rotate speed of electric engine, pouring temperature and mould temperature to the distribution of primary crystal and Mg₂Si particles, design three different pouring technologies. Fifteen trunk-like parts are formed adopting these technologies.Observe the metallurgical structure and test area percentage of primary crystal particle of these parts casting by these technologies. The results show that gradient distribution of primary crystal and Mg₂Si particle is very obvious and area percentage of primary crystal and Mg₂Si particle reduces gradually from the border to the centre. It states that the higher of the mould temperature, rotate speed of centrifugal machine and pouring temperature, the more obvious gradient distribution of primary crystal and Mg₂Si particle.