Provided is a welding method using a special torch and a flux cored wire, in which the special torch has a suction nozzle between the contact tip and the shield nozzle, and the flux cored wire has a flux filled inside the steel outer casing, and a seam portion where both ends of a metal in a width direction of the steel outer casing are butted or overlapped in a longitudinal direction of the flux cored wire.

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 of F-equivalent values is 0.21% or more, oxides of which the total value of amounts ranges from 0.30% to 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 0.20%. An amount of iron powder ranges from 0% to less than 10.0%. A Y-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 2.50%. A ratio of to 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%. A chemical composition excluding the fluorides, the oxides, the CaO, the carbonates, and the iron powder is within a predetermined range. Ceq ranges from 0.10% to 0.44%.

The present invention relates to processes for producing fluorine-containing compounds by means of precipitation reactions from solutions containing fluoride ions wherein the pH value is determined using an electrochemical measuring chain and to electrochemical measuring chains for determining pH values.

Non-hygroscopic brazing fluxes, methods for producing non-hygroscopic brazing fluxes, and methods for producing hydrated cesium aluminum fluorides are provided. An exemplary method for producing a non-hygroscopic brazing flux includes preparing a mixture including aluminum, cesium, and fluorine. The prepared mixture has an aluminum:cesium:fluorine molar ratio of about (1):(1.1-1.2):(4.0-4.2). The method further includes drying the mixture at a temperature higher than about 90 C. to form a product comprising at least about 20 mass percent hydrated cesium aluminum fluoride, based on the total mass of the product.

A flux-cored wire for carbon dioxide gas shielded arc welding including, in terms of % by mass with respect to a total mass of the wire, 0.03 to 0.08% of C, 0.2 to 0.7% of Si, 1.4 to 3.0% of Mn, 0.01 to 0.5% of Cu, 0.8 to 3.0% of Ni, 0.05 to 0.5% of Ti, 0.002 to 0.015% of B, 0.05% or less of Al, 4 to 8% in terms of TiO.sub.2, 0.1 to 0.6% of in terms of SiO.sub.2, 0.02 to 0.3% in terms of Al.sub.2O.sub.3, 0.1 to 0.8% of Mg, 0.05 to 0.3% in terms of F, 0.05 to 0.3% in terms of Na and K in a fluorine compound, 0.05 to 0.2% of Na.sub.2O and K.sub.2O, and 0.2% or less in terms of ZrO.sub.2.

A purpose of the present invention is to provide a flux-cored wire that excels in slag removability and weldability, and is capable of high-efficiency operation without the risk of reheat cracking and makes it possible to obtain a welding bead with high corrosion resistance even when used in equipment operating at high temperature for a long time. The present invention relates to a flux-cored wire for gas-shielded arc welding that is used for welding using a specific shielding gas having a high Ar ratio, includes substantially no As, Sb, Pb and Bi, has slag component and alloy component compositions satisfying predetermined conditions, and satisfies the relationship {(3??O.sub.2?)+?CO.sub.2?+(0.0085?A.sup.2)?(0.19?A)}?20.0 (where A={?Cr?+(4.3??Nb?)}).

Disclosed is an aluminum composite material including an aluminum alloy material containing magnesium, and a bonding material formed by brazing using a flux, the bonding material being adapted to bond the aluminum alloy material thereto. In the aluminum composite material, the bonding material contains a magnesium-containing compound other than KMgF.sub.3 and MgF.sub.2. The present invention provides an aluminum composite material with satisfactory brazeability to an aluminum alloy material containing magnesium, a heat exchanger including the aluminum composite material, and a flux suitable for use in braze.

A method of treating a superalloy article, including selecting an article having a superalloy composition, whereby the article has a treatable feature on its surface. The method further includes removing a base alloy from a region abutting a first portion of the treatable feature. The method further includes treating a second portion of the treatable feature with a treatment composition to remove surface oxides. The method further includes inserting a treatment material into the first portion of the treatable feature followed by depositing the base alloy in the first portion of the treatable feature. The method further includes heat treating the article at a temperature above the melting point of the treatment material whereby the treatment material flows into the second portion of the treatable feature forming a treated article.

This brazing flux composition for an aluminum alloy is characterized by containing [A] a flux component containing KAlF.sub.4 and [B] a fluoride that does not contain K and that contains elements other than group 1 elements and group 2 elements: being in a particle form of single component of [B] the fluoride; and the added amount (C) (mass %) of [B] the fluoride with respect to [A] the flux component and the average particle size (d) (m) satisfying formula (1),

0.83C0.19d<43(1).

A wire including, in terms of % by mass with respect to a total mass of the wire, as a total in a steel outer skin and a flux, 0.03 to 0.08% of C, 0.1 to 0.6% of Si, 1.2 to 2.5% of Mn, 0.01 to 0.5% of Cu, 0.5 to 1.5% of Ni, 0.05 to 0.5% of Ti, 0.002 to 0.015% of B, and 0.05% or less of Al, and further including, in the flux, 4 to 8% in terms of TiO.sub.2, 0.1 to 0.6% of in terms of SiO.sub.2, 0.02 to 0.3% in terms of Al.sub.2O.sub.3, 0.1 to 0.8% of Mg, 0.05 to 0.3% in terms of F, 0.05 to 0.3% in terms of Na and K in a fluorine compound, 0.05 to 0.2% of Na.sub.2O and K.sub.2O, and 0.2% or less in terms of ZrO.sub.2.