A coating composition for a heat exchanger tube including vanadium (V), a flux, and a binder, wherein the vanadium is included in an amount of 28 to 38 parts by weight with respect to 100 parts by weight of the composition, and a coating method of a heat exchanger tube using the same are provided.

The present invention provides a consumable electrode type gas shield arc welding method for performing arc welding of two steel sheets using a welding torch having a consumable electrode. The consumable electrode type gas shield arc welding method includes performing arc welding while a shielding gas having an oxygen potential which is indicated by the following Expression (1) and ranges from 1.5% to 5% is supplied from the welding torch toward the consumable electrode, and blowing an oxidation promotion gas having an oxygen potential which is indicated by the following Expression (2) and ranges from 15% to 50% at a flow velocity ranging from 1 to 3 m/sec over a weld bead and a weld toe portion which are formed by arc welding and are in a state of 700 C. or higher,
=100([V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)]/5)/([V.sub.1(X)]+[V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)])Expression (1)
=100[V.sub.2(O.sub.2)]/([V.sub.2(X)]+[V.sub.2(O.sub.2)]+[V.sub.2(CO.sub.2)])Expression (2) here, [V.sub.1(X)] is a mixing ratio (volume %) of an inert gas included in the shielding gas, [V.sub.1(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the shielding gas, [V.sub.1(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the shielding gas, [V.sub.2(X)] is a mixing ratio (volume %) of an inert gas included in the oxidation promotion gas, [V.sub.2(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the oxidation promotion gas, and [V.sub.2(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the oxidation promotion gas.

A radial bearing having a wear surface with improved wear characteristics comprises a steel support, to which is bonded a metal carbide composite wear surface made by first arranging, within a cavity defined between a steel mold and the steel support, tiles made of microwave sintered, cemented metal carbide, closely packing the voids between the tiles with metal carbide powder, and infiltrating the mold cavity with a metal brazing alloy by subjecting the filled mold to rapid heating. The brazing alloy fills voids between the metal carbide particles, the microwave sintered metal carbide tiles, and the metal support, thereby relatively rapidly consolidating the carbide into a wear layer bonded with the steel support without substantially damaging the properties of the microwave-sintered metal carbide tiles.

The present invention relates to a welding wire including a solid wire of metal that has a tensile strength of 800 MPa or more, in which the welding wire has a cast of 300 mm or more and a helix of 20.0 mm or less. The welding wire may include a coating layer including Cu or a Cu alloy on an outer periphery of the solid wire.

The present invention consists in a method of welding a nickel strength lug with a bronze connecting pin and a brass contact ring in an accelerometer sensor, the strength lug being interleaved between the connecting pin and the contact ring, the welding being effected electrically with the strength lug pressed simultaneously against the connecting pin and the contact ring. Before welding, the strength lug undergoes deformation of its external surface at least on each of two portions of the surface respectively facing the connecting pin and the contact ring, the surface deformation creating on each of the portions asperities intended to come into local contact with the connecting pin and the contact ring, respectively.

A plurality of welding torches, which are disposed in a welding device and are made movable in three-dimensional directions, are provided with welding wires that differ in composition and diameter from each other. When welding is performed in the horizontal direction, an arc is generated by at least two of the welding torches to form a bead while the welding wires are being fed. When welding is performed in the vertical direction, the arc is generated by any one welding torch of the two welding torches to form a bead while the welding wire is being fed. Thus, a steel sheet to which an anti-corrosion material has been applied can be welded continuously with high quality and high-efficiency in a horizontal orientation and vertical orientation.

In a mixed composition coating material for brazing, when a total mass of a solid material, an organic solvent, and water is defined as 100 mass %, the solid material are contained in an amount of 30 mass % or greater and 80 mass % or less with respect to the whole coating material, the organic solvent and the water is contained in a total amount of 20 mass % or greater and 70 mass % or less with respect to the whole coating material, and the water is contained in an amount of 0.4 mass % or greater and 2.5 mass % or less with respect to the whole coating material.

A radial bearing having a wear surface with improved wear characteristics comprises a steel support, to which is bonded a metal carbide composite wear surface made by first arranging, within a cavity defined between a steel mold and the steel support, tiles made of microwave sintered, cemented metal carbide, closely packing the voids between the tiles with metal carbide powder, and infiltrating the mold cavity with a metal brazing alloy by subjecting the filled mold to rapid heating. The brazing alloy fills voids between the metal carbide particles, the microwave sintered metal carbide tiles, and the metal support, thereby relatively rapidly consolidating the carbide into a wear layer bonded with the steel support without substantially damaging the properties of the microwave-sintered metal carbide tiles.

The present invention provides a consumable electrode type gas shield arc welding method for performing arc welding of two steel sheets using a welding torch having a consumable electrode. The consumable electrode type gas shield arc welding method includes performing arc welding while a shielding gas having an oxygen potential a which is indicated by the following Expression (1) and ranges from 1.5% to 5% is supplied from the welding torch toward the consumable electrode, and blowing an oxidation promotion gas having an oxygen potential which is indicated by the following Expression (2) and ranges from 15% to 50% at a flow velocity ranging from 1 to 3 m/sec over a weld bead and a weld toe portion which are formed by arc welding and are in a state of 700 C. or higher,

=100([V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)]/5)/([V.sub.1(X)]+[V.sub.1(O.sub.2)]+[V.sub.1(CO.sub.2)]) Expression (1)

=100[V.sub.2(O.sub.2)]/([V.sub.2(X)]+[V.sub.2(O.sub.2)]+[V.sub.2(CO.sub.2)]) Expression (2)

here, [V.sub.1(X)] is a mixing ratio (volume %) of an inert gas included in the shielding gas, [V.sub.1(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the shielding gas, [V.sub.1(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the shielding gas, [V.sub.2(X)] is a mixing ratio (volume %) of an inert gas included in the oxidation promotion gas, [V.sub.2(O.sub.2)] is a mixing ratio (volume %) of oxygen included in the oxidation promotion gas, and [V.sub.2(CO.sub.2)] is a mixing ratio (volume %) of carbon dioxide included in the oxidation promotion gas.

Provided is an aluminum alloy tube with superior corrosion resistance and a joining layer for brazing. In addition, a heat exchanger using a fin which utilizes a bare material of low cost and higher availability, rather than a clad material, is provided. A manufacturing method of an aluminum alloy tube, including the steps of forming a sacrificial anticorrosion layer comprising Zn, by ark spraying Zn with purity of 95% or more, onto a surface of aluminum alloy tube with a spraying amount of 3 to 10 g/m.sup.2 and a spraying speed of 15010.sup.3 to 35010.sup.3 mm/sec; and forming a joining layer for brazing by applying a joining material for brazing comprising a mixture obtained by mixing Si powder with purity of 95% or more and flux, onto a surface of the sacrificial anticorrosion layer, so that the amount of the Si powder is 1.2 to 3.0 g/m.sup.2, is provided.