Inclusion Removal in Molten Magnesium by Pulsed Electric Current

Abstract

The effect of pulsed electric current on the removal of MgO inclusions, which deteriorate mechanical and corrosion properties of magnesium alloys, was investigated. Through characterizing the number and size distribution of MgO inclusions, it's found that the MgO inclusions were expelled to the surface (bottom and top) of the magnesium alloy melt and then absorbed by the coating agent, treated by the electropulsing. Besides, the electropulsing also promoted the aggregation of the inclusions, but the large size inclusion only exists on the surface of the sample. Based on the differences in electrical properties between the inclusions and the magnesium alloy melt, a force from electric current to electrically neutral MgO inclusion has been identified to drive the particles' movement. Further, the results of numerical calculation show that under the action of pulse current, the migration of inclusions to the surface can reduce the system free energy, and the aggregation tendency between two inclusions with a relatively large radius is significantly stronger than the two inclusions with a smaller radius. The excellent agreement between numerical calculations and experimental data demonstrates that employing the electropulsing to separate the particles from the liquids is a fantastic new method in metal melt purification.

Theory and Practice of Using Pulsed Electromagnetic Processing of Metal Melts

“…In recent works devoted to ECP, the main focus of the authors is on studying the effect of such an effect on non-metallic inclusions in the melt. Zhang et al [ 38 ] analyzes the refining ability of pulse processing on the example of the industrial magnesium alloy AZ31. The observed changes in the distribution of MgO inclusions were as follows: in the untreated metal, MgO inclusions were distributed almost uniformly along the height of the ingot; in the treated with the electric impulse action, the predominant arrangement of inclusions in the lower and upper parts of the ingot was observed, while the number of inclusions in the center was small.…”

State‐of‐the‐Art in the Control of Sulfides in Steels

“…[ 140–144 ] There are also a few researches on the impact of EPT on the evolution of inclusions. [ 145–147 ]…”

Effect of an AC Magnetic-field on the Dead-zone Range of Inclusions in the Circular Channel of an Induction-heating Tundish

“…Qi ZHANG, 1) * Guangye XU 2) and Kazuhiko IWAI 2) the motion of inclusions when an AC magnetic-field was applied. Taniguchi et al [18][19][20] used the trajectory method to solve the removal efficiency of nonmetallic inclusions in the molten steel with the AC magnetic-field.…”

“…It is very significant to increase the cleanliness of liquid steel to meet the requirements of high-quality steel. 1,2) As the last refractory container of a metal-casting system, the tundish is the key to ensure continuous metal-casting. [3][4][5] To enable suitable flow conditions and avoid/reduce inclusions in the tundish, different systems, such as inhibitors, dams, weirs, and baffles are commonly used to control flow.…”