An aluminum alloy brazing sheet used for brazing in an inert gas atmosphere without using a flux includes a brazing material cladded onto at least one side surface of a core material. An oxide is formed on a surface of the aluminum alloy brazing sheet by brazing heating, the oxide including any one or two or more of Mg, Li, and Ca and having a volume change ratio of 0.990 or less to a surface oxide film formed before brazing heating, and an atomic molar ratio of Mg, Li, and Ca to Al in the oxide formed on the surface of the aluminum alloy brazing sheet before brazing heating is 0.50 or less. The present invention provides an aluminum alloy brazing sheet having excellent brazability in brazing in an inert gas atmosphere without using a flux, and a method for manufacturing the same.

A heat exchanger includes tube expansion portions provided respectively on a plurality of heat transfer tubes such that outer peripheral surfaces of the heat transfer tubes are respectively pressed against inner peripheral surfaces of a plurality of first holes provided in a side wall portion of a case, and a plurality of first concave surface portions provided in an outer surface of the tube expansion portion so that first gaps, into which brazing material of a first brazed portion advances, are formed between the outer surface of the tube expansion portion and the inner peripheral surface of the first hole. At least one of the plurality of first concave surface portions is positioned in an outside peripheral surface portion of the outer peripheral surface of the heat transfer tube. According to this configuration, the strength with which the heat transfer tubes are attached to the case can be increased while simplifying a manufacturing operation and reducing the manufacturing cost.

The invention relates to a method of manufacturing a brazing sheet product having a core layer of a 3xxx-series aluminium alloy clad on one or both sides with a 4xxx-series aluminium alloy brazing layer, the method comprising the steps of: (i) casting a rolling ingot of the core layer of a 3xxx-series aluminium alloy having the following composition, in wt. %: Mn 0.5-1.8, Si≤1.5, Fe≤0.7, Cu≤1.5, Mg≤1.0, Cr≤0.25, Zr≤0.25, Ti≤0.25, Zn≤0.5, balance impurities and aluminium; (ii) hot rolling of the rolling ingot to a hot rolled sheet having thickness of 2.5-10 mm; (iii) cold rolling of the hot rolled sheet to a gauge of 0.1-4 mm, optionally with an intermediate annealing step during the cold rolling operation; (iv) soft annealing to recrystallize the microstructure of the aluminium sheet, preferably at a temperature in the range of 250° C.-450° C.; (v) further cold rolling of the soft annealed sheet with a cold rolling reduction in the range of 5% to <10% to a final cold rolling thickness; and (vi) recovery annealing at 200° C.-420° C. of the cold rolled aluminium sheet at final cold rolling thickness.

A method for repairing solder joint leakages on a connection unit designed to feed cooling water into hollow metallic stator bars of a stator winding of an electrical machine. A welding or soldering apparatus is designed for carrying out the method.

A process for building a high-performance liquid flow-through plate is provided and includes providing a substrate formed of metal matrix composite (MMC) material, metallizing a surface of the substrate to reform the surface into a metallized surface, placing a braze foil on the metallized surface and executing a high-temperature and high-pressure bake whereby material of the braze foil diffuses into the metallized surface.

A method for joining a first metal part with a second metal part, the metal parts having a solidus temperature above 1100° C., includes applying a melting depressant composition on a surface of the first metal part, the melting depressant composition including a melting depressant component that includes at least 25 wt % boron and silicon for decreasing a melting temperature of the first metal part; bringing the second metal part into contact with the melting depressant composition at a contact point on said surface; heating the first and second metal parts to a temperature above 1100° C.; and allowing a melted metal layer of the first metal component to solidify, such that a joint is obtained at the contact point. The boron at least partly originates from a boron compound selected from any of the following compounds: boric acid, borax, titanium diboride and boron nitride. The melting depressant composition and related products are also described.

A refrigerant pipe that constitutes a refrigerant circuit of a refrigeration apparatus includes: a first pipe; and a second pipe. The first pipe includes: a first pipe body, made of stainless steel; and a first connection, made of a material different from stainless steel, disposed at an end of the first pipe body in a pipe axial direction of the first pipe body. The second pipe includes: a second pipe body, made of stainless steel; and a second connection, made of a material identical to the material of the first connection, disposed at an end of the second pipe body in a pipe axial direction of the second pipe body. The first connection is connected to the second connection.

A heat exchanger includes: a header that guides a refrigerant; and an assembly of heat transfer tubes and fins that is connected to the header and that causes heat exchange between the refrigerant and a medium. The header includes: a first member having a first surface; a second member having a second surface that faces the first surface; and third member having a third surface that intersects with the first surface and the second surface. The first surface is joined with the second surface by a first brazing material having a first thickness. The third surface is joined with the first member by a second brazing material having a second thickness. The third surface is joined with the second member by the second brazing material. The first thickness is less than the second thickness. The first thickness is 0.2 mm or less.

A heat exchanger brazing fixture including a baseplate including a first surface and a second surface located opposite the first surface and a first post including a first end and a second end located opposite the first end. The first post is operably associated with the first surface of the baseplate at the first end. The A heat exchanger brazing fixture further including a top plate operably connected to the first post and separated from the first surface of the baseplate by a selected distance. The top plate being configured to move in a first direction along the first post when a heat exchanger resting upon the first surface of the baseplate expands during a brazing process.

A brazeable metal sheet material for heat exchanger components is used for producing a heat exchanger by a controlled atmosphere brazing process. The metal sheet material is made up of a core material with a brazing layer at least on one side and a corrosion-reducing intermediate layer arranged between the brazing layer and the core material. The core material consists of an Al3000-series alloy or an Al6000-series alloy having a magnesium content of 0.1% to 1.5% by weight. The brazing layer consists of an Al4000-series alloy having a maximum of 0.2% magnesium by weight. The corrosion-reducing intermediate layer consists of an Al1000-series alloy or an Al7000-series alloy having 0.1% to 1.5% magnesium by weight.