Induction spool for casting round ingots of ferrous metals and alloys - using inset pieces of high resistivity at current connections to correct electromagnetic field within spool

摘要

Round metal ingots are (semi-) continuously cast by means of an induction spool which is circular in form, constructed of a hollow box section material and connected at two points to current feed and discharge cables, the connections being divided by an insulating shield set radially into the spool. On each side of the insulating shield, there are inset pieces of a material with a specific resistivity pref. of the order of 40 to 60 times greater than that of the spool material itself. The function of the inset pieces which are box shaped, pref. three times as long as the width of the spool section with their inner walls lying against the inner wall of the spool, is to concentrate the induction current along the inner face of the spool at the cable connection points thereby ensuring that the induced mangetic field within the spool is uniform. The incorporation of the inset pieces ensures that the cross-section of the cast ingot is uniformly round and undisturbed at the face opposite to the current connections on the spool.