The conclusion of a Q&A with our resident brazing expert about combining aluminum brazing and heat treatment. Part 1 can be found here. We pick up where we left off last time.
D. There are a number of so-called “multi-bar” vacuum furnaces out there that can be used for rapid quenching of parts inside the vacuum furnace. Since a “bar” is approximately equal to about one full atmosphere of pressure, a “10-bar” furnace would be a vacuum furnace whose door can be sealed so that it can operate as a “pressure cooker,” allowing a gaseous atmosphere to be build up inside the furnace to the equivalent of 10-atmospheres of pressure. That’s a lot of pressure! Such multi-bar furnaces have very powerful circulating fans and heat exchangers built in so that very rapid cooling/quenching of many different kinds of metals by those rapidly circulating gases can effectively be achieved. Manufacturers of specialized vacuum furnaces for aluminum brazing should be consulted to see what they can manufacture to meet your particular needs.
E. Some furnace manufacturers claim to have built an “oil-quench” (synthetic fluids) capability into a separate chamber within their vacuum furnace design so that heat-treated parts can be moved, while still under vacuum, into a separate chamber in that furnace that holds an actual quench tank into which the parts can be dumped/dropped.
F. So, can someone vacuum-braze 6061 components, allow for full, normal furnace cooling to ensure proper BFM solidification and then solution heat treat those same brazed parts adequately, including the needed quenching? Yes, it may be possible, but it should be explored further with a vacuum furnace manufacturer by any interested end user looking for this capability.