| 摘要 |
<p>A non-consumable electrode for striking and maintaining the arc in a metal crucible contains a coil producing a magnetic field. The lines of force at the top of the electrode are perpendicular to the arc, and cause it to rotate around the tip. The removable, annular top, of U-shaped vertical cross-section is made of copper alloy, with an external graphite crown. It seals theinner and outer of three co-axial tubular walls of the electrode body, providing a circulatory path for cooling fluid. Its centre is closed by a refractory plug which protects the coil which may also incorporate cooling passages. Rotation of the arc around the top reduces electrode consumption. The removable tip facilitates replacement when worn. The design ensures adequate cooling and reduces problems of differential expansion. Electric supply tp the top may be through the coil. If independent control fo the magnetic field is required the coil is insulated from the tip, and two separate supplies are provided.</p> |
