Provided is a heat exchanger, in particular for motor vehicles, with at least one exchanger tube of an aluminium alloy and with at least one component connected fluidically to the exchanger tube, wherein the exchanger tube and the component (14, 16) are connected to one another by way of a common soldered connection and wherein the component connected to the exchanger tube has a core layer of an aluminium alloy with the following composition: Si: max. 0.7% by weight, Fe: max. 0.70% by weight, Cu: max. 0.10% by weight, Mn: 0.9-1.5% by weight, Mg: max. 0.3% by weight, Cr: max. 0.25% by weight, Zn: max. 0.50% by weight, Ti: max. 0.25% by weight, Zr: max. 0.25% by weight, unavoidable impurities individually max. 0.05% by weight, altogether max. 0.15% by weight, the remainder aluminium.

Disclosed is an amorphous, ductile brazing foil with a composition consisting essentially of Ni.sub.restCr.sub.aB.sub.bP.sub.cSi.sub.d with 2 atomic percent≦a≦30 atomic percent; 0.5 atomic percent≦b≦14 atomic percent; 2 atomic percent≦c≦20 atomic percent; 0 atomic percent≦d≦14 atomic percent; incidental impurities≦0.5 atomic percent; rest Ni, where c>b>c/15 and 10 atomic percent≦b+c+d≦25 atomic percent. Also disclosed is amorphous, ductile Ni-based brazing foil having a composition consisting essentially of Ni.sub.restCr.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eX.sub.fY.sub.g wherein a, b, c, d, e, f, and g are numbers such that 2 atomic percent≦a≦30 atomic percent; 0.5 atomic percent≦b≦14 atomic percent; 2 atomic percent≦c≦20 atomic percent; 0 atomic percent≦d≦14 atomic percent; 0 atomic percent≦e≦5 atomic percent; 0 atomic percent≦f≦5 atomic percent; 0 atomic percent≦g≦20 atomic percent; wherein incidental impurities are present, if at all, in amounts≦0.5 atomic percent; wherein rest indicates that the balance of the composition is Ni; wherein c>b>c/15; wherein 10 atomic percent≦b+c+d≦25 atomic percent, wherein X is one or more of the elements Mo, Nb, Ta, W and Cu; and wherein Y is one or both of the elements Fe and Co. Also disclosed are methods for making and using these brazing foils, and brazed objects produced therefrom.

A surface treatment method capable of imparting exceptional corrosion resistance and moisture resistance to an NB heat exchanger. The method includes subjecting an NB heat exchanger to a chemical conversion treatment to form a chemical conversion film on the surface thereof using a chemical conversion treatment agent that contains zirconium and/or titanium in a total amount of 5-5,000 ppm by weight, vanadium in an amount of 10-1,000 ppm by weight, and has a pH of 2-6; bringing the NB heat exchanger on whose surface the chemical conversion film is formed into contact with a hydrophilization agent containing a hydrophilic resin and a guanidine compound and/or a salt thereof; and baking the NB heat exchanger subjected to the contacting process, whereby a hydrophilic film is formed on the surface thereof.

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.

A method for brazing is provided, in which an amorphous or partially amorphous brazing foil, having a composition with a metalloid content of 10 to 30 at. %, is arranged at a joining point of two or more parts. The brazing foil is in the form of a wound ring-shaped strip which has a short-circuited current path between at least two layers lying one on top of the other. The brazing foil inductively heated, melted and a brazed connection of the parts is produced.

A method for joining heat transfer plates, comprising: applying a melting depressant composition on individual application areas of a first metal sheet, each application area comprising a mid-section and two end-sections; pressing ridges and grooves in the metal sheet, the ridges extending in a direction that extends between the end-sections of the application areas, such that the application areas are located on top of the ridges; bringing the metal sheet into contact with a second, pressed metal sheet, such that contact points are formed where the mid-sections of the application areas re located; heating the sheets until melted metal is formed at the application areas where the melting depressant composition is applied; and allowing the melted metal to solidify such that a joint is obtained at the contact points.

An apparatus, material and method for forming a brazing sheet has a composite braze liner layer of low melting point aluminum alloy and 4000 series braze liner. The low melting point layer of the composite braze liner facilitates low temperature brazing and decrease of the diffusion of magnesium from the core into the composite braze liner. The reduction of magnesium diffusion also lowers the formation of associated magnesium oxides at the braze joint interface that are resistant to removal by Nocolok flux, thereby facilitating the formation of good brazing joints through the use of low temperature controlled atmosphere brazing (CAB) and Nocolok flux. The apparatus also enables the production of brazing sheet materials with high strength and good corrosion property.

A double pipe includes an outer pipe, an inner pipe, a fin member and a sealing part. The outer pipe has a plurality of outer crimping parts projecting to an inner diameter side and aligned in at least one of a lengthwise direction and a circumference direction. The inner pipe is arranged on an interior of the outer pipe with a flow path gap being defined between the outer pipe and the inner pipe. The inner pipe has a plurality of inner crimping parts aligned in the at least one of the lengthwise direction and the circumference direction and overlapping the outer crimping parts. The fin member is arranged on the interior of the inner pipe and held by the inner crimping parts. The sealing part seals between the outer pipe and the inner pipe.

A method for manufacturing a heat exchanger includes stacking a plurality of parting sheets, a plurality of lengthwise closure bars, and a plurality of widthwise closure bars to form a rectangular first heat exchanger section. The first heat exchanger section includes at least one widthwise passage extending between a pair of the widthwise closure bars and at least one lengthwise passage extending between a pair of the lengthwise closure bars. The method also includes brazing the rectangular first heat exchanger section together and cutting a first side and a second side of the rectangular first heat exchanger section to give the first heat exchanger section a tapered-trapezoid profile. The method further includes brazing an end of a second heat exchanger section to the first or second side of the first heat exchanger section.

The present application relates to a stencil device (150) for simultaneous stencil printing of brazing material onto elevations, areas surrounding port openings, and a circumferential skirt (210) of a heat exchanger plate (200) wherein the stencil device (150) comprises an upper stencil having openings for applying brazing material to elevations and areas surrounding port openings of the heat exchanger plate (200) and a lower stencil printing stencil (150) having a large opening (190) for receiving the heat exchanger plate (200) and contacting an outer perimeter of the circumferential skirt (210) of the heat exchanger plate (200), wherein an inner surface (195) of the large opening (190) comprises brazing material exits (160) for applying brazing material to the circumferential skirts (195). Disclosed is also a method of such stencil printing and also the use of a stencil device for applying heat exchanger plates (200) with a brazing material.