| 摘要 |
901,333. Welding by fusion. AIR REDUCTION CO. Inc. March 24, 1959 [April 2, 1958], No. 10214/59. Class 83 (4). [Also in Group XXXV] In arc welding using a continuously fed wire electrode, the current source has a voltage below that required to sustain an arc so that the electrode repeatedly and rapidly contacts the weld pool, and the supply circuit has substantial inductive reactance to limit the shortcircuit current and to extend the duration of the arc. The short circuits are at a frequency of 40 . . . 250 per second and metal is removed from the electrode only when a short circuit occurs. The voltage is 1 . . . 10 volts below that required to sustain an arc. The supply source is D.C. of either polarity, has a constant or rising volt-ampere characteristic and is a motor-driven generator, a transformer-rectifier set or a battery. The welding circuit has an inductive reactance of 40 ... 1,000 microhenries of which part may be inherent in the circuit and part added. The current time graph of Fig. 7 relates to a process in which the arc is sustained until short-circuit occurs. That shown in Fig. 9 relates to a process in which the arc breaks down before short-circuit occurs. The process is particularly applicable to the welding of mild steel using a shield of carbon dioxide. Other shielding gases referred to are nitrogen helium and argon + 1% oxygen. Specifications 687,666, 712,259 and 713,507 are referred to. |
