A brazing sheet may be used for brazing under an atmosphere of an inert gas without flux. The brazing sheet may include at least three layers. The at least three layers may include a core material, a brazing material layer, and an intermediate layer. The at least three layers may be cladded by an outermost layer of the brazing material layer. The intermediate layer may be disposed on a face of the core material. The core material may be composed of a first aluminum alloy including at least one of (i) 0.20 weight % to 1.0 weight % of Cu, (ii) 0.8 weight % to 1.8 weight % of Mn, and (iii) 0.25 weight % to 1.5 weight % of Mg. The intermediate layer may be composed of a second aluminum alloy including 0.20 weight % or less of each of Si and Fe and 0.10 weight % or less of each of Cu, Mn, and Cr.

A plate heat exchanger has two metal plates brought into abutment, with a solder material between the plates. The plates are heated up to a first temperature. The plates are placed into a mold, the mold surfaces of which have cavities for envisaged channel structures. Channel structures are formed by local internal pressure forming of at least one plate under pressurization by the tool. The plates are heated up to a second temperature. The plates are solder bonded at the abuted surfaces. A plate heat exchanger has two metal plates, wherein channel structures have been formed in at least one plate and the plates are bonded to one another by soldering away from the channel structures. Eutectic microstructures having a longest extent of less than 50 micrometers are formed in the solder layer.

To provide a water heat exchanger, a manufacturing method of the water heat exchanger, and a refrigeration cycle apparatus capable of preventing corrosion of a brazing material and deterioration of a refrigerant. The water heat exchanger according to the present embodiment includes a plurality of stacked heat-exchange plates, a joint (9) provided on at least one cover plate (14) of a pair of cover plates sandwiching the plurality of heat exchange plates, a first refrigerant pipe (10) brazed to the joint (9) by a brazing material (11), and a protector (12) provided to prevent contact between the brazing material (11) and the refrigerant circulating to the plurality of heat exchange plates through the first refrigerant pipe (10) and the joint (9).

The present invention reduces and mitigates thermal stress generated at joint portions between a header plate and a flat tube of a heat exchanger. In a direction of a vertical center axis passing the center of the inside of a flat tube, positions of first brazing parts are set to be closer to the center of the flat tube in the direction of the vertical center axis than positions of edge brazing parts. Accordingly, the thermal stress concentrated at the joint portions between short sides of the flat tube and the header plate is dispersed to other portions.

The invention relates to a plate heat exchanger for a process engineering plant, comprising a heat exchanger block which has a plurality of alternatingly arranged heating surface elements and separating plates, wherein the separating plates are soldered to the heating surface elements with the aid of solder layers provided at the separating plates, and wherein, in at least a part of the separating plates, the solder layers comprise at least two soldered areas that differ in terms of the alloy composition thereof.

The present invention relates to a pipe connection assembly of a heat exchanger for connecting a header tank and a pipe of the heat exchanger, in which a means for preventing a welding ring that fixes a manifold and a pipe from entering into a hollow at one end of the manifold before welding is disposed, and a space is formed between the inner surface of the one end of the manifold and the outer surface of the pipe, thereby preventing the molten welding ring from flowing out.

A sacrifice positive electrode layer is formed conveniently, efficiently, and accurately on the surface of a refrigerant distributor having a complicated shape. Further, during the formation of the sacrifice positive electrode layer, the strength in the surroundings of joined parts is prevented from being lowered by excessive heating. Included are: an applying step of applying flux to remove an aluminum oxide to a surface of a plurality of outflow sections and a distributing section; an alloy disposing step of disposing a zinc-containing aluminum-silicon alloy on the surface to which the flux is applied; a forming step of forming the sacrifice positive electrode layer on the surface by heating the disposed zinc-containing aluminum-silicon alloy; a brazing material disposing step of inserting a plurality of outflow pipes into the plurality of outflow sections, respectively, and disposing an aluminum-silicon alloy brazing material on the surface of the outflow sections; and a brazing step of brazing the plurality of outflow sections with the plurality of outflow pipes, respectively, by heating the aluminum-silicon alloy brazing material.

A heat dissipation substrate for increasing solderability is provided. The heat dissipation substrate for increasing solderability includes a heat dissipation layer serving as a base layer, a plating layer formed on the heat dissipation layer, and a protective layer formed on the plating layer. The protective layer is made of one of tin and tin alloy, and the protective layer is capable of being melted in a subsequent process, such that the protective layer is a meltable protective layer.

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 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.