Effect Of Electric Field On Melting And Solidification Behavior Of Electroslag Remelting Process

Electroslag remelting is a secondary refining process that integrates melting and solidification.It can effectively remove impurity elements and non-metallic inclusions in metals to improve the mechanical properties and compactness of materials.As we all know,the current can affect the distribution of inclusions in the metal melt and its solidification quality,and the electroslag remelting itself is a process of refining the steel by using the Joule heat generated by the remelting current,but the effect of the electric field on the melting and solidification behavior in the electroslag remelting process is not clear,which seriously restricts the optimization of the refining and solidification quality of the molten steel in the electroslag remelting process.Therefore,it is of great significance to study the effect of remelting current on the melting and inclusion behavior and solidification process of electroslag remelting.In this thesis,the influence of current on the melting and solidification process of electroslag remelting was studied by combining numerical simulation with physical experiment.Ansys Fluent and Procast software were used to simulate the steady-state temperature field,electromagnetic field and flow field coupling of single and double electrode electroslag remelting under different remelting currents,and the inclusion behavior and microstructure growth during transient melting process.The effects of different currents in single and double electrodes on slag pool temperature,electromagnetic force,rate,inclusion behavior and solidification behavior were obtained.In addition,the electroslag remelting dripping experiment and the molten steel energization experiment were carried out by physical simulation to explore the variation of electrical parameters during the dripping process and the influence of current on inclusions in molten steel.The results show that:（1）With the increase of remelting current from 3000 A to5000 A,the maximum current density,electromagnetic force,Joule heat,temperature and velocity in single and double electrode electroslag remelting increase,and the double electrode method has better kinetic and thermodynamic conditions.（2）When the current increased from 3000 A to 5000 A,the removal rate of inclusions with 1μm and 10μm increased from 88.41%and 95.60%to 92.37%and 99.58%,respectively.The removal rate of inclusions with 1μm and 10μm increased from 91.44%and 96.52%to 95.11%and 99.76%,respectively.This shows that with the increase of current,the removal rate of inclusions in single and double electrode electroslag remelting increases and the removal effect of inclusions in double electrode is more significant.（3）The change of remelting current before and after the droplet drops first increases and then decreases.When the droplet is formed and stretched,the increase of the effective conductor area in the slag pool is equivalent to the decrease of the resistance in the system,resulting in the increase of the current and reaching the peak value.After the droplet drops completely,the effective conductor area decreases and the resistance increases,so that the current gradually decreases and the current value cannot return to the previous level.（4）By introducing 2 V and 5 V constant voltage currents into the molten steel,the number of inclusions in the ingot is significantly reduced,and the removal effect of inclusions is better after adding slag.The inclusions parallel to the current direction attract each other,and the inclusions perpendicular to the current direction repel each other.（5）When the GCr15 bearing steel ingot with the size ofφ140mm×360 mm is remelted,the current increases from 3000 A to 5000 A,and the local solidification time and the secondary dendrite arm spacing decrease first and then increase with the increase of current,and reach the extreme value when the current is4000 A,indicating that most of the electroslag remelting steel grades have an optimal current value to achieve the best solidification quality.（6）Combining the simulation results with previous studies,the regression equation of current and secondary dendrite spacing for remelting GCr15 bearing steel can be deduced:λ₂=185.114-0.029I+3.542×10^-6I²。...