Abstract
The authors studied the vacuum ingot-casting from June, 1955.
The first degassing unit was put in operation in September 1957, and, in addition, 3 units were developed. At the present time, they can make 4 ingots with 6t to 20t continuously.
Special features of vacuum ingot casting process are as follows:
(1) The oxidation of the pouring stream and surface of the steel are prevented as there is no oxygen in the vacuum chamber.
(2) When the steel enters the vacuum, the steel stream is divided up into little drops with diameter of 1μ to 10mm.
(3) The sources of hydrogen from bricks and patching are eliminated.
(4) There is a greater latitude with regard to the pouring speed.
(5) The scum and non-metallic inclusions are floated by the violent boiling and bubbling.
(6) Under the vacuum 2mmHg to 5mmHg, 60% of hydrogen and 30% of oxygen are removed.
