| 摘要 |
<p>A process for making a soldered joint between two members, one of which may comprise aluminum. The ends of the members to be joined are formed with sufficient clearance so that they can easily be telescoped, but preferably so that telescoping of the members forms a tight fit at a tapered neck to temporarily, frictionally retain the members in assembled relation. Prior to telescoping, either one or both of the members is coated with a layer of zinc solder so that after telescoping a layer of solder is disposed in the clearance space between the members in the region of overlap. The members are then partially submerged in a molten zinc solder bath and ultrasonic energy is applied only to the molten solder. The solder between the members is heated to its melting temperature which causes it to flow and break the surface tension at the interface with the solder bath so that solder from the solder bath flows into and completely fills the clearance space between the joint members. The ultrasonic energy can then penetrate into the region between the two members to clean the surfaces of the members without any direct contact between the ultrasonic transducer and the members being joined. When the members are withdrawn from the molten solder, the solder solidifies between them to form a permanent joint. The porcess is especially adapted for joining return bends of multi-row heat exchangers because the ends of the heat exchangers can be moved through the molten solder bath without direct contact with the ultrasonic transducers.</p> |
