Abstract: An improved practice for the vacuum brazing of aluminum alloy workpieces in a multi-chamber braze furnace is disclosed. When magnesium-containing aluminum alloys are brazed in a furnace having a braze chamber and adjacent exit chamber, there may be advantage in providing thermal barriers between a load of hot brazed workpieces and the furnace walls of the exit chamber.

Abstract: An improved practice for the vacuum brazing of aluminum alloy workpieces in a multi-chamber braze furnace is disclosed. When magnesium-containing aluminum alloys are brazed in a furnace having a braze chamber and adjacent exit chamber, there may be advantage in providing thermal barriers between a load of hot brazed workpieces and the furnace walls of the exit chamber.

Abstract: Heat exchanger cores comprising an assembly of elongated vertical and horizontal parts are brazed by induction heating in a vacuum chamber where the magnetic heating field is disposed at an angle to the vertical and horizontal planes for uniform heating. Steel supports for strength and durability are used to hold the cores in the vacuum chamber. A pair of elongated steel fixtures engage opposite sides of each heater core, the fixtures having recesses at their outboard surfaces. A rectangular frame having a pair of support rods is held by brackets within the chamber to orient the plane of the frame parallel to the magnetic field to minimize electrical heating of the frame. The recesses in the fixtures engage the support rods of the frame in a manner to hold the vertical parts in a vertical plane and to prevent rotation of the core by action of the magnetic field on the core.

Abstract: A heat exchanger assembly is formed of spaced parallel headers connected by an array of spaced flat tubes each in a plane perpendicular to the headers. The header and tube material is clad with a brazing alloy which melts at a temperature slightly below the melting point of the base material. Sinuous metallic ribbons fill the spaces between the flat tubes. The assembly is induction heated by a low frequency alternating magnetic field having its flux lines extending transversely of the tubes and headers and at oblique angles thereto, the angles being selected to cause equal heating thereof for obtaining a uniform temperature throughout the assembly to effect the melting of the alloy and the brazing of the joints. Heat panels heated by the magnetic field to a temperature near that of the assembly are placed opposite outer surfaces of the assembly as required to avoid a radiation loss which would cause a significant temperature differential.