| 摘要 |
A process and an apparatus for producing spirally-seamed tubing from metal strip are disclosed. The edges (15) of the metal strip (12) are prepared and the metal strip is fed into a generally cylindrical forming head (13) to bring the prepared edges of the strip closely adjacent one another in overlapping relationship, and the overlapping edges are welded together by means of inner and outer electrode rollers (16, 17). A conducting strand (18) is fed round the rotary electrodes to pass between the rollers and the strip and so provide continuously fresh electrical contacts. The conducting strand (18) may comprise a copper wire which is fed from a supply coil (19), round one roller (16), through a cleaning device (24), round the other roller (17), and then to waste. |
