抄録
VAD (Vacuum Arc Degassing) plant is characterized by 3-phase AC are heating under reduced pressure while Ar gas is injucted by a porous plug set at the bottom of ladle. Thus alloying, desulphurizing, oxygen reduction and dehydrogenation can be made easily and sufficiently. For instance, the sulphur concentration can be easily achieved to less than 0.005%, the oxygen level of the slab of low alloy steels ranges between 10 and 35 ppm, and, the hydrogen in the molten steel after degassing is 1.5 ppm on an average.
At Kure Works, high grade carbon steels and low alloy steels, such as structural steels, tool steels and bearing steels, and extra low carbon steels (carbon concentration is less than 0.005%) are produced economically by this plant from the molten steel of LD converters. This paper describes the techniques procedure for manufacturing these steels by this LD-VAD process.
