低炭素フェロクロムの極低窒素化と, それを用いた高純度ステンレス鋼の溶製について

抄録

The process of denitriding of low carbon ferrochromium and vacuum melting of high purity stainless steel with the denitrided ferrochromium were investigated.
(1) A pile of granular ferrochromium can be denitrided uniformly with Mg-MgCl₂ flux of more than 70-90 kg/t without mechanical stirring.
(2) Under the condition that the terminal nitrogen content of ferrochromium is independent of its size, the influences of temperature, amount of flux, and initial nitrogen content can be explained thermodynamically as the equilibrium state is reached.
(3) The optimum size of ferrochromium is 1-5 mm∅.
(4) In VIF, if solid oxide is mixed in granular ferrochromium, the prevention of mitrogen absorption is possible owing to decarburization during melting. The denitrided granular ferrochromium is a suitable chromium source for the high purity, especially ultra low nitrogen, stainless steel.