Investigation On The Feeding Rules Of Electromagnetic Induction Heating Riser

Casting is widely used in various industries such as military equipment manufacturing,aerospace,automobile and ship manufacturing.The foundry industry plays an important role in strengthening our national defense power and national economic development.The quality of castings is the largest problem in the development of foundry industry in China.Therefore,it is necessary to continuously improve and develop casting quality control techniques to produce high-quality casting products.In order to solve the problem of shrinkage cavity and porosity in castings,an induction heating riser was developed according to the principle of electromagnetic induction heating.This method can combine the effects of indirect heating with direct heating to the melt in the riser,thus prolonging the solidification time of metal liquid in the riser,and can solve the problems of large size,low feeding efficiency and environmental pollution of the existing risers in the production practices.In the paper,a cylindrical aluminum alloy casting with the diameter of 90 mm and the height of 100 mm was determined as the research object.After calculation and several numerical simulations,a riser with the diameter of 60 mm and the height of 140 mm was designed to carry out the investigation on the feeding effects of induction heating riser on the determined casting.By designing three groups of comparison experiments,the feeding effects of risers on ZL101 aluminum alloy cylindrical castings with a common riser,with an electromagnetic induction heating riser,and with an electromagnetic induction heating riser containing a steel sleeve,were investigated,respectively.The research results show that the feeding effect of the electromagnetic induction heating riser on the cylindrical casting is much better than that of the conventional riser.It was found that the electromagnetic induction heating can change the temperature field distribution of the riser and facilitate the smooth filling of the molten metal in the riser into the casting,thus eliminating the shrinkage porosity defects of the casting.The research results also show that the feeding effect of the electromagnetic induction heating riser containing a steel sleeve is better than that riser containing no sleeve.In order to further explore the feeding effect of the induction heating riser with a heating sleeve,according to the liquid shrinkage volume of the casting,the induction heating riser with the diameter of 40 mm and the height of 40 mm was designed and the actual experiment was carried out.The research results show that there is no shrinkage defect generated in the casting,and the process yield of the casting reaches 78.4% at this time.In the paper,the effects of the current and frequency of the induction power supply on the feeding channel of the induction heating riser were studied.It is shown that increasing the current and/or frequency can prolong the closing time of the feeding channel.The influence of pouring temperature on the feeding channel was also simulated.It is concluded that the closing time of feeding channel can be prolonged by increasing the pouring temperature properly.At the same time,the distribution of electromagnetic force in the induction heating riser was simulated and analyzed.The results show that the direction of electromagnetic force is more conducive to the feeding of liquid metal in the induction heating riser.