(1) Cleaning before welding. It is not difficult to process the oxide film of copper and common copper alloys. Mechanical cleaning or sandpaper polishing can be used to remove the oxide film on the surface to be welded and chemically clean the oil. However, the Al203 oxide film on the surface of aluminum bronze and aluminum brass is difficult to remove.
(2) Brazing methods Copper and copper alloys can be brazed by soldering iron, wave crest, flame, induction, resistance, and furnace heating.
1) In the brazing of oxygen-containing copper furnace, hydrogen-containing atmosphere cannot be used, and large parts can not be brazed by flame to avoid hydrogen embrittlement.
2) Brazing in a brass furnace should avoid the evaporation of zinc, and brazing should be performed after the surface is plated with copper.
3) Lead-containing copper alloys are easy to cause lead to precipitate when heated for a long time, so care must be taken to prevent them.
4) When brazing aluminum bronze, in order to prevent the diffusion of aluminum to the silver solder, the heating time should be as short as possible, and the surface can also be prevented by plating steel or nickel.
5) For soft brazing of iron-green steel, it is advisable to choose a solder with a solder temperature lower than 300℃ to prevent aging softening; for brazing, choose a solder with a solidus temperature higher than the quenching temperature (780℃), and then quench after soldering. A aging treatment.
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