373 / | HD | INDUSTRIAL ELECTRIC HEATING FURNACES |
60 | DF | ARC FURNACE DEVICE {9} |
61 | .~ Indirect {3} | |
62 | DF | .~.~> Arc between spaced electrodes {2} |
65 | DF | .~.~> Arc between electrode and crucible exterior |
66 | DF | .~.~> Combined with or convertible to direct arc furnace |