Effect Of Electrode Form On Droplet Behavior And Molten Metal Pool Structure In Electroslag Remelting Process

The main characteristics of electroslag remelting products are high purity and uniform density of ingot,which can effectively restrain common quality defects such as loose and segregation.However,the development of high-end manufacturing of electroslag ingot demand is higher and higher,especially for ingot cross section size of large scale and high alloying of steel ingot content,to control the defects such as osteoporosis,segregation problem put forward the higher request,this to the traditional electroslag remelting technology has brought great challenges,how to adjust and optimize the electroslag remelting process so as to adapt to the development of high-end manufacturing requirements become scientific problems to be solved.The results show that changing the electrode form can effectively improve the quality of electroslag remelting products.In particular,in recent years,scholars have proposed to replace the traditional one electrode form with pipe electrode and two series electrodes,and preliminary positive results have been achieved.However,due to the lack of research on how electrode form changes affect the electroslag remelting process,it is difficult to put forward reasonable technological parameters of electroslag remelting,which hinders the industrialization process of electroslag remelting process with pipe-electrode and electroslag remelting process with two series electrodes.To solve this problem,the one electrode,pipe electrode and electroslag remelting process with two series electrodes are simulated numerically based on the sequential coupling method.The electromagnetic field,flow field and temperature field of the three processes are calculated by the multi-physical steady-state model,and the results are used as the initial conditions of the electrode melting transient model and the metal melting pool transient model to study the droplet formation and dropping behavior and the structure of the metal melting pool during the electroslag remelting process.In order to physically simulate the electroslag remelting process with different electrode forms,wood alloy was used to replace the consumable electrode and Na Cl solution to replace the slag to conduct physical simulation experiments in this study,and the influence law of one electrode,pipe electrode and electroslag remelting process with two series electrodes on the formation and dripping behavior of droplet during the electroslag remelting process was explored.The results show that:(1)compared with the single electrode electroslag remelting,electroslag remelting process with pipe-electrode can produce relatively small droplets,improve the effect of the nonmetallic inclusion removal,but the melting rate is lower than electrosalg remelting with one electrode,electroslag remelting with pipe electrode remelting rate is significantly lower than that of one electrode electroslag remelting,reduces the production efficiency.Under the same loading conditions,the depth of the one electrode electroslag remelting molten metal pool is 0.1188 m,and the depth of the pipe electrode molten metal pool is 0.0962 m.Compared with one electrode,the slope of metal pool is smaller,and the pool is shallower and flatter.(2)Compared with the one electrode electroslag remelting process,the electroslag remelting process with two series electrodes can realize the unification of high melting rate and shallow leveling pool.Compared with the results without droplet effect,the numerical simulation results of coupled droplet effect are more accurate.(3)In the process of electroslag remeltingwith two series electrodes,electrode proximity effect inhibited skin effect and made the Joule heat concentrate between two electrodes in the slag pool.Under the influence of proximity effect,the inner region of two electrode tips melts first,and the molten steel converges at the electrode tip to form the droplet source.During the stretching and necking stages,the increase of contact area between the droplet and slag and the instantaneous increase of current provide good thermodynamic and kinetic conditions for the removal of non-metallic inclusion.