An aluminum alloy brazing sheet is formed of a brazing material, an intermediate material, a core material, and a brazing material. The intermediate material contains Mg of 0.40 to 6.00 mass %, and has total of contents of Mn, Cr, and Zr being 0.10 mass % or more. The core material contains Mg of 0.20 to 2.00 mass % and one or two or more of Mn of 1.80 mass % or less, Si of 1.50 mass % or less, Fe of 1.00 mass % or less, Cu of 1.20 mass % or less, Ti of 0.30 mass % or less, Zr of 0.30 mass % or less, and Cr of 0.30 mass % or less. Each of the core material and the intermediate material has a grain size of 20 to 300 μm, and each of the brazing materials contain Si of 4.00 to 13.00 mass %.

An aluminum alloy brazing sheet includes a four-layer material containing an intermediate layer formed of an aluminum alloy including Mn of from 0.2 to less than 0.35 mass %, Si of 0.6 mass % or less, Fe of 0.7 mass % or less, and Cu of 0.1 mass % or less, with the balance being Al and inevitable impurities, a core material formed of an aluminum alloy including Si of 1.2 mass % or less, Fe of 1.0 mass % or less, Cu of from 0.3 to 1.0 mass %, and Mn of from 0.5 to 2.0 mass %, with the balance being Al and inevitable impurities, and each of an air-side brazing material layer and an internal brazing material layer is formed of an aluminum alloy including Si of from 4 to 13 mass %, with the balance being Al and inevitable impurities.

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.

The present invention relates to a steel material composite having at least two layers (1, 2, 3, 4), comprising at least one first layer (1, 3) of a material-removable and/or shearable steel and at least one second layer (2, 4) of a formable steel, cohesively bonded to the first layer (1, 3).

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.

An apparatus, material and method for forming a brazing sheet has a high strength core bonded with corrosion protection layer on the coolant side and/or layers on both airside and coolant side. The material enables heat exchanger components, such as tube, header, plate, etc., for applications, such as automotive heat exchangers, that require high fatigue life as well as high service life in a corrosive environment.

An apparatus, material and method for forming a reliably roll-bonded, multi-layer aluminum alloy brazing sheet has a core of 2XXX, 3XXX, 5XXX or 6XXX alloy, a braze liner of 4XXX alloy and an interliner with Mn in the range of 0.2 to 1.0 wt. % and Si in the range of 0.31-1.0 wt. %. Alternatively, Mg in the range of 0.1 to 0.5 wt. % may be present in the interliner. Additional layers such as a second braze liner may be present for providing an inner surface of a heat exchanger. An additional interliner may optionally be used between the core the inner surface layer. The material may be used for highly corrosive environments like an EGR cooler.

A strip intended for the manufacture of brazed heat exchangers, having a core made of an aluminium alloy with the composition (weight %): Si: 0.10-0.30%, preferably 0.15-0.25% Fe<0.20% Cu: 0.75-1.05%, preferably 0.75-1.02%, more preferably 0.75-1.0% Mn: 1.2-1.7%, preferably 1.2-1.55%, more preferably 1.25-1.4% Mg<0.03% preferably <0.025%, more preferably <0.015% Zn<0.1% Ti<0.15% other elements <0.05% each and <0.15% in total, remainder aluminium.

To improve adhesion between a plating film reducing contact electrical resistance and a copper alloy plate containing Mg. A copper alloy plate containing Mg of more than 1.2% by mass and 2% by mass or less and the balance Cu and inevitable impurities in a center portion in a plate thickness direction, in the copper alloy plate, a surface Mg concentration at a surface is 30% or less of a center Mg concentration at the center portion in the plate thickness direction, a surface layer portion having a depth from the surface to where a Mg concentration is 90% of the center Mg concentration is provided, and in the surface layer portion, the Mg concentration increases from the surface toward the center portion of the plate thickness direction with a concentration gradient of 0.2% by mass/μm or more and 50% by mass/μm or less.

A method for manufacturing a heat exchanger (1) includes joining an inner fin (3) to a hollow structure (20) formed from at least two clad plates (200a, 200b) by heating and brazing a filler metal layer (B). Each clad plate has a core layer (A) composed of an aluminum alloy that contains Mg: 0.40-1.0 mass %. The filler metal layer is composed of an aluminum alloy that contains Si: 4.0-13.0 mass %, and further contains Li: 0.0040-0.10 mass %, Be: 0.0040-0.10 mass %, and/or Bi: 0.01-0.30 mass %. The inner fin is composed of an aluminum alloy that contains Si: 0.30-0.70 mass % and Mg: 0.35-0.80 mass %. A flux (F) that contains cesium (Cs) is applied along a contact part (201), and the vicinity thereof, of the at least two clad plates prior to the heating. A heat exchanger (1) may be manufactured according to this method.