A flux-cored wire for arc welding, including a steel sheath filled with flux, where the wire contains, relative to a total mass of the wire, Cr: 16.0 to 22.0 mass %, Ni: 6.0 to 11.0 mass %, Mn: 0.7 to 2.6 mass %, Si: 0.1 to 1.1 mass %, Zr: 0.2 to 0.8 mass %, Fe: 45.0 to 65.0 mass %, TiO.sub.2: 5.0 to 9.0 mass %, SiO.sub.2: 0.1 to 2.0 mass %, ZrO.sub.2: 0.5 to 3.0 mass %, and Bi: less than 0.0020 mass %. Where by mass %, a Si content is denoted by [Si] and a Zr content is denoted by [Zr], a value of parameter A expressed by A=[Si]+2×[Zr] satisfies 1.4 to 2.5.

According to an aspect of the present invention, there is provided a flux-cored wire including a steel sheath and a flux that fills the steel sheath. The flux contains fluorides of which a total value α of F-equivalent values is 0.21% or more, oxides of which the total value β of amounts ranges from 0.30% to less than 3.50%, and carbonates of which a total value of amounts ranges from 0% to 3.50%. An amount of CaO ranges from 0% to less than 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A X-value is 5.0% or less. The amount of CaF.sub.2 is less than 0.50%. The amount of Ti oxides ranges from 0.10% to less than 2.50%. A ratio of α to β ranges from 0.10 to 4.00. A total value of amounts of MgCO.sub.3, Na.sub.2CO.sub.3, and LiCO.sub.3 ranges from 0% to 3.00%. Other chemical composition is within a predetermined range. Ceq ranges from 0.45% to 1.20%.

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.

In an application method of a solid brazing material, while being rotated, the solid brazing material is brought into contact with an aluminum plate material, thereby applying the solid brazing material to the aluminum plate material.

A flux cored welding electrode includes a ferrous metal sheath and a core within the sheath including core ingredients, the core ingredients including, in weight percent based on the total weight of the flux cored welding electrode: 2.0-3.0 aluminum, 1.0-2.0 manganese, and 0.001-0.5 rare earth metal oxide including three or more of Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Praseodymium (Pr).

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO.sub.2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF.sub.2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO.sub.2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF.sub.2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.

The present invention relates to a flux-cored wire for positive polarity gas-shielded arc welding use, in which a flux contains a metal powder and also contains BaF.sub.2 and SrF.sub.2 and AlF.sub.3 and/or CaF.sub.2 as fluorides wherein the content of BaF.sub.2 is 1.0 to 4.5%, the content of SrF.sub.2 is 2.0% or less, the content of CaF.sub.2 is 0.45% or less and the content of AlF.sub.3 is 0.70% or less, at least one of metal elements constituting the flux and the fluorides is a strong deoxidizing metal element having a specified standard formation Gibbs energy, and the content of each of an oxide and a carbonate in the flux is 0.5% or less.

A method is provided for passivating an aluminum surface. According to the method, the aluminum surface is provided with a flux. A passivation solution is subsequently applied to the aluminum surface, such that a passivation layer is created by reaction of the passivation solution with the aluminum surface, which is provided with the flux.

The invention concerns a method for the manufacturing of a clad sheet product comprising a core layer (6) and at least one cladding layer, the method comprising rolling an assembly of a core layer and at least one cladding layer and reducing the thickness to a desired gauge, the core layer being made of an aluminium alloy, the at least one cladding layer comprising a centre section (2) and at least two edge sections (4, 5) positioned at opposite sides of the centre section (2) along the edges of the at least one cladding layer, the centre section being made of a material being an aluminium alloy or a composite material comprising a matrix of aluminium or an aluminium alloy, the edge sections along (4, 5) the edges being made of a material different from the material of the centre section, wherein the edge sections (4, 5) are cut off during or after the rolling. The invention further concerns a cladding plate useful in the method.