Process for restricted lead content soldering of copper with controlled copper contamination of the molten solder reservoir

摘要

This is a process which provides the first essentially continuous high tin flow soldering method for attaching copper-based fins to non-copper- based tubing. This invention avoids sludge buildup in the reservoir and generally avoids lead carbonate formation when the heat produced having a braze-like joint with eta phase layers exchanger is in service. In addition, a novel structure is adjacent to copper-containing surfaces. The invention utilizes an essentially lead-free, high tin solder cascade onto a preferably cool tube, genrally with a limited time of contact between the liquid solder and the tube, and with a combination air quench and wipe to remove excess solder and solidify the remaining solder. Thus a braze-like joint is achieved having better heat conduction and closer thermal expansion match. This finned heat exchanger tubing is generally useful for liquid to gas-type heat exchangers.