A tube transition fitting includes a body having a scalloped end having a raised portion and a depressed portion connected by a continuously sloping transition portion. The fitting is formed having a first wall thickness and a second wall thickness. A tube seat is formed on a surface connected to the body, the surface being adjacent a transition from the first wall thickness to the second wall thickness. A tube transition assembly includes a header portion, the tube transition fitting, and a heat exchange tube, each being connected using one or more simplified and/or heat-optimized connections.

Multilayered brazing sheet material including an aluminium core alloy layer having a first brazing clad layer material on one face of the core layer and a second brazing clad layer material on the other face of the core material, and an inter-layer between the core layer and the first brazing clad layer material, wherein the core layer is 3xxx-series aluminium alloy having, in wt. %, up to 0.4% Si, up to 0.5% Fe, 0.4% to 0.75% Cu, 0.6% to 1.1% Mn, up to 0.04% Mg, up to 0.2% Cr, up to 0.25% Zr, up to 0.2% Ti, up to 0.15% Zn, balance aluminium and impurities, wherein the first brazing layer and the second brazing layer are 4xxx-series aluminium alloy having 7% to 14% Si and up to 2% Mg, balance aluminium and impurities, and wherein the inter-layer is aluminium alloy of the 1xxx-series alloys.

A method is disclosed for connecting two components by TIG welding, the components consisting of an air-hardening steel alloy and, for example, of the material T23 or T24. A joint is produced between the components that are to be connected, said joint widening, in particular, from an inside toward an outside. First, a root layer is welded in the region of the inside. Subsequently, a fill layer adjoining the root layer is welded, so that the joint is at least 90% filled. Finally, a cover layer is welded onto the fill layer, whereby the welding parameters are prespecified in such a manner that a temperature in an optimizing temperature range is adjusted on the inside in the region of the root layer.

A surface treatment method for aluminum heat exchangers including (a) a step wherein a chemical conversion coating film is formed on the surface of an aluminum heat exchanger by subjecting the aluminum heat exchanger to chemical conversion using a chemical conversion agent; (b) a step wherein the aluminum heat exchanger, the surface of which has been provided with a chemical conversion coating film in step (a), is brought into contact with a hydrophilizing agent that contains a hydrophilic resin; and (c) a step wherein a hydrophilized coating film is formed on the surface of the aluminum heat exchanger by baking the aluminum heat exchanger, which has been subjected to a contact treatment in step (b). The chemical conversion agent used in step (a) contains zirconium and/or titanium in an amount of 5-5,000 ppm by mass in total, vanadium in an amount of 10-1,000 ppm by mass and a metal stabilizer in an amount of 5-5,000 ppm by mass. In addition, the chemical conversion agent used in step (a) has a pH of 2-6.

A heat sink includes a plurality of layers being disposed substantially parallel with a surface of a heat source. The layers include a plurality of pin portions spaced apart from each other in a planar arrangement wherein the pin portions of the layers are stacked and bonded to form pin fins extending in a transverse direction relative to the heat source to sink heat. A compliant layer is disposed between the pin fins and a mechanical load. The compliant layer provides compliance such that the pin fins accommodate dimensional differences when interfacing with the heat source.

A brazed heat exchanger, for example a heat exchanger to be used in an air-conditioning system, preferably as a condenser, includes flat tubes extending between a pair of header tubes and fins arranged between the flat tubes. The components are produced from aluminum alloys, and are brazed together using an AlSi braze alloy. The aluminum alloys have a zinc content of no greater than 0.5% before brazing, and zinc from the aluminum alloys diffuses into the braze joints to result in braze joints having an average zinc content of no greater than 0.1%.

A tube used in a heat exchanger, wherein a tube body includes a curved end portion, a pair of parallel portions, a pair of inclination portions, and a fixed portion in which a long end part extending from one of the pair of inclination portions is bent to hold therebetween a short end part extending from the other of the pair of inclination portions, and the tube is a pipe member having a flattened shape in cross-section. Poor brazing is reduced by making the inclination angle of at least part of the other inclination portion with respect to the flat plate portion larger than that of the one inclination portion.

The invention relates to a welding head for magnetic pulse welding of hollow thin-walled profile to an inner member having a complementary outer form to said hollow thin-walled profile. The weld head comprises two movable weld head halves (10a,10b) forming said weld head wherein each half has at least one individual induction coil (12a,12b) connected to a power source independently from the other weld head half, with coils wound in a kidney-shape. The work piece is clamped between shapers (15a,15b) integrated with each half. With this weld head could for example work pieces such as tubular thin-walled profiles be welded, even if they are integrated in a closed tubular design, as the weld head could be closed quickly over the welding position and opened for release of the work piece without experiencing arching in clamping area.

A hollow aluminum structure that will be brazed includes at least one brazing sheet having a filler metal layer clad onto a core layer. The core layer is composed of aluminum or an aluminum alloy containing less than 0.2 mass % Mg. The filler metal layer is composed of an aluminum alloy that contains Si: 4.0-13.0 mass % and Bi: 0.01-0.3 mass %, and further contains Li: 0.004-0.08 mass % and/or Be: 0.006-0.12 mass %, the filler metal layer containing less than 0.1 mass % Mg. The hollow aluminum structure is assembled such that the filler metal layer is present at locations that will form both an interior-facing brazed joint and an exterior-facing brazed joint. Then, flux is applied onto the filler metal layer at the location that will form the exterior brazed joint, and the hollow aluminum structure heated in an inert gas atmosphere to form the interior brazed joint and the exterior brazed joint.

A heat exchanger includes: a header that extends in a first direction; and a plurality of heat transfer tubes that extend in a second direction crossing the first direction, each of which has one end connected to the header, and that are arranged in the first direction at intervals. The header includes: a header body having a tubular shape, a first member through which the one end of each of the heat transfer tubes extends, and a second member positioned between the header body and the first member in the second direction. The second member includes: a base portion that extends in the first direction, and a plurality of protruding portions that extend from the base portion toward the first member in the second direction.