Effects of relative motion between consumable electrodes and mould on solidification structure of electroslag ingots during electroslag remelting process

Abstract

Steel solidification process control, especially in the solidification process of high alloy steel, and improvement of the solidification structure have been increasingly gaining interest among metallurgists, particularly the electroslag workers. To further develop the electroslag remelting (ESR) process and to improve the advantage of the ingot solidification structure, the effects of relative motion between the consumable electrodes and the mould (namely, mould rotation) on chemical element distribution were observed in this study, as well as the compact density changes in electroslag ingots. Experiment results show that applying relative motion between the mould and the consumable electrodes in ESR results in a more uniform chemical element distribution in the electroslag ingots. Compared with the electroslag ingot of conventional ESR, maximum segregation of carbon could decrease from 3·19 to 1·146, and statistical segregation decreased from 0·2636 to 0·0608. Maximum segregation of chromium could decrease from 1·316 to 1·253, and statistical segregation decreased from 0·2753 to 0·1201. The compact density for the stationary mould increased from 0·7693 to a compact density of 0·9501 for the rotating mould. The improvement in the solidification structure of the electroslag ingot can be attributed to mould motion, which led to the generation of a shallow pool and the improvement of the solidification structure. But the excessive rotation rate is harmful to solidification structure instead due to the molten metal pool motion caused by violent slag pool motion.