| 373 / | HD | INDUSTRIAL ELECTRIC HEATING FURNACES |
| 60 | DF | ARC FURNACE DEVICE {9} |
| 71 | | .~ Furnace body detail {4} |
| 72 | DF | .~.~> Hearth or crucible |
| 73 | DF | .~.~> Roof {1} |
| 75 | DF | .~.~> Sidewall {1} |
| 77 | DF | .~.~> With internal atmosphere control (e.g., pressure, vacuum, etc.) |