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.

A brazing material for brazing aluminum or an aluminum alloy includes fluoride-based flux, a solidifying agent, and a coating film uniformity agent, and is solid at 25° C.

Iron-based braze filler alloys having unexpectedly narrow melting temperature ranges, low solidus and low liquidus temperatures, as determined by Differential Scanning calorimetry (DSC), while exhibiting high temperature corrosion resistance, good wetting, and spreading, without deleterious significant boride formation into the base metal, and that can be brazed below 1,100 C contains a) nickel in an amount of from 0% to 35% by weight, b) chromium in an amount of from 0% to 25% by weight, c) silicon in an amount of from 4% to 9% by weight, d) phosphorous in an amount of from 5% to 11% by weight, e) boron in an amount of from 0% to 1% by weight, and f) the balance being iron, the percentages of a) to f) adding up to 100% by weight. The braze filler alloys or metals have sufficient high temperature corrosion resistance to withstand high temperature conditions of Exhaust Gas Recirculation Coolers.

Provided is a brazed aluminum member brazed with a member formed of a brazing sheet, in which two or more grooves are provided on a surface of the brazed aluminum member in a fillet forming area, a groove depth (D1) of the grooves is 0.005 mm to 0.50 mm, a groove width (W1) of the grooves is 0.005 mm to 0.50 mm, a ratio (W1/D1) of the groove width (W1) to the groove depth (D1) is 10.00 or less, and a space (P1) between adjacent grooves is 0.00 mm to 0.30 mm. The present invention can provide an aluminum material and a method for producing a brazed product that can secure good brazing properties even when the clearance between the jointed members is large in the case where the aluminum material is brazed without using a flux.

Provided is a brazed aluminum member brazed with a member formed of a brazing sheet, in which two or more grooves are provided on a surface of the brazed aluminum member in a fillet forming area, a groove depth (D1) of the grooves is 0.005 mm to 0.50 mm, a groove width (W1) of the grooves is 0.005 mm to 0.50 mm, a ratio (W1/D1) of the groove width (W1) to the groove depth (D1) is 10.00 or less, and a space (P1) between adjacent grooves is 0.00 mm to 0.30 mm. The present invention provides an aluminum alloy material and a method for manufacturing a brazed body that can secure good brazing properties even when the clearance between the jointed members is large in the case where the aluminum material is brazed without using a flux.

An aluminum alloy bare material for a member to be brazed by flux-free brazing to a brazing sheet including a brazing material formed of an aluminum alloy that includes 3.00 to 13.00 mass % of Si and 0.10 to 2.00 mass % of Mg with the balance being Al and inevitable impurities, in which the aluminum alloy bare material for the member to be brazed is formed of an aluminum alloy including 0.004 to 6.00 mass % of Zn and 0.004 to 3.00 mass % of Mg with the balance being Al and inevitable impurities. According to the present invention, aluminum alloy materials can be provided for members to be well brazed to the brazing sheet with the brazing material including Mg when an aluminum material is brazed by flux-free brazing.

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 flux composition includes a component (A) that is a powder of an alkali metal zinc fluoroaluminate represented by “M.sub.wZn.sub.xAl.sub.yF.sub.z (1)” (wherein M is K or Cs, and w, x, y, and z are a positive integer, the greatest common divisor of w, x, y, and z being 1), the content of the component (A) in the flux composition being 50 mass % or more. The flux composition prevents occurrence of a brazing defect and discoloration even when an aluminum alloy is brazed in an atmosphere having a high oxygen concentration, or an atmosphere having high humidity.

An aluminum alloy fin material has a composition, in % by mass, of the following: Zr: 0.05 to 0.25%, Mn: 1.3 to 1.8%, Si: 0.7 to 1.3%, Fe: 0.10 to 0.35%, and Zn: 1.2 to 3.0%, the remainder being Al and inevitable impurities. The aluminum alloy fin material has a solidus temperature of 615° C. or higher, a tensile strength after brazing of 135 MPa or higher, a pitting potential after brazing in the range of −900 to −780 mV, and an average crystal grain diameter in a rolled surface after brazing in the range of 200 μm to 1,000 μm.

An aluminum alloy brazing sheet has a 3XXX, 1XXX or 6XXX core, an interliner and a 4XXX brazing layer without added Mg. The interliner has Bi and Mg, the magnesium migrating to the surface of the brazing sheet during brazing and reducing the aluminum oxide to facilitate brazing without flux in a controlled inert atmosphere with reduced oxygen.