Temperature Rising Characteristic Of Induction Heating Riser And It’s Application On Typical Flat Steel Casting

Riser is the key technology to solve the problems of shrinkage cavity, porosity, gas exhaust, and drag collecting in steel casting production, and it is an important part of the foundry technical process. At present, the risers commonly used in casting processes have the problems of over large size and low feeding efficiency. Therefore, it is of practical significance to develop a new type of riser to solve these problems. In the paper, based on the theory of electromagnetic thermal effect, a new type of electromagnetic induction heating riser was designed and invented to improve the technological yield and inner quality of steel castings.The finite difference method was adopted to establish the heat transfer model of the induction heating riser. Taking the riser of 100 mm in diameter and 200 mm in height as an example, for the graphite sleeve of the induction heating riser to be heated to 1000℃ in 10 min, the induction power was numerically calculated and should be set as 32 kW. The heating experimental results and simulation results were in good agreement, verifying the accuracy of the numerical simulation. Through many times of calculation, the relationship between the riser diameter and the induction power was determined and the corresponding curve was plotted out.Using the ProCAST software, the solidification time of 35# carbon steel in various sizes of risers of large plate castings was calculated, and according to the rule of the same solidification time, the corresponding relationship between the sizes of the induction heating riser and the ordinary riser was determined. Taking the plate casting in size of 400mm×160 mm×40 mm with the material of 35# steel as an example, based on the calculation results of riser sizes and casting modulus, three groups of comparative experiments were practically carried out, namely the plate casting with the ordinary riser in diameter of 100 mm, with the induction heating riser in diameter of 60 mm and with the ordinary riser in diameter of 60 mm, respectively. Both the simulation and practical experimental results show that the plate casting with the induction heating riser in diameter of 60 mm has no shrinkage defects, while with the ordinary riser in the same size, the shrinkage cavity occurs in the plate casting. It has proved that the electromagnetic induction heating riserhas higher feeding efficiency.