| 摘要 |
<p>Welding is achieved by at least two electrodes, which are connected to one or more sec. windings of a transformer, of which the prim. winding is fed with AC. A foil or strip made of an alloy of Cu and a metal compatible with the coating on the steel sheets is inserted between each electrode and the sheets. The foil or strip pref. contains 60-65% Cu and 35-40% Zn, i.e. a brass. The pref. spot welding machine contains two electrodes driven by jacks towards or away from the sheets to be welded. A cassette contg. a spool (a) on which a brass strip is wound is used for the stepwise feeding of the strip between one electrode and the sheet; the strip then travels back to the cassette and is wound onto a second spool (b). A second cassette is used in the same manner for the other electrode. The process is used for steel sheet coated with Zn by electroplatg. or by dipping in molten Zn, eliminating the need for frequent cleaning of the electrodes.</p> |
