A flux (55) for superalloy laser welding and additive processing (20, 50), including constituents which decompose when heated in a laser induced plasma or to a melt temperature of the superalloy (42), creating one or more gases (46) that blanket the melt to protect it from air, while producing not more than 5 wt. % of slag relative to the weight of the flux. Embodiments may further include compounds providing one or more functions of surface cleaning, scavenging of impurities in the melt, and elemental additions to the superalloy.

A method of soldering a shape memory alloy (SMA) element to a component includes positioning a tinned end of the SMA element with respect to a surface of the component, and then directly soldering the tinned end to the surface using solder material having a low liquidus temperature of 500 F. or less when an oxide layer is not present on the SMA element. The end may be soldered using lead-based solder material at a higher temperature when an oxide layer is present. The end may be tinned with flux material containing phosphoric acid or tin fluoride prior to soldering the SMA element. The SMA element may be submersed in an acid bath to remove the oxide layer. The solder material may contain tin and silver, antimony, or zinc, or other materials sufficient for achieving the low liquidus temperature. Heat penetrating the SMA element is controlled to protect shape memory abilities.

This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system includes a gas supply system configured to provide a fluorine-containing gas flow. The system also includes a wire supply system configured to provide welding wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the fluorine-containing gas flow and the welding wire and to deliver the fluorine-containing gas flow and the welding wire near the welding arc during the SAW.

In a stainless steel flux cored wire comprising a stainless steel shell and a flux filling the shell, the amount of Si contained in the entire wire is 2.5% by mass or higher, preferably 3.0% by mass or higher in terms of SiO.sub.2, and the amount of at least one compound selected from the group consisting of polytetrafluoroethylene, graphite fluoride and perfluoropolyether contained in the flux is 0.005 to 0.10% by mass of the total mass of the wire in terms of F, preferably 0.020% by mass or higher. By employing such a constitution, in welding of CrNi-based and Cr-based stainless steels and other materials, fume generation and hexavalent chromium leaching can be significantly reduced, and excellent welding workability can be provided.

A heat-exchanger tube has a tube main body composed of an aluminum alloy. A coating is applied onto a surface of the tube main body. The coating contains a powder mixturewhich includes: 1 g/m.sup.2 or more and 7 g/m.sup.2 or less of an Si powder, 0.2 g/m.sup.2 or more and 4.0 g/m.sup.2 or less of a Zn powder, 0.5 g/m.sup.2 or more and 5.0 g/m.sup.2 or less of a first flux powder composed of a compound that contains Zn, and 5 g/m.sup.2 or more and 20 g/m.sup.2 or less of a second flux powder composed of a compound that does not contain Znand a binder. The total amount of the powder mixture in the coating is 30 g/m.sup.2 or less. The proportion of the binder in the coating is 5-40 mass %.

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.

The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. Further, the core includes a carbon source and an agglomerate having a Group I or Group II compound, silicon dioxide, and titanium dioxide. Additionally, the carbon source and the agglomerate together comprise less than 10% of the core by weight.

This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system includes a gas supply system configured to provide a gas flow. The system also includes a wire supply system configured to provide welding wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the gas flow and the welding wire and to deliver the gas flow and the welding wire near the welding arc during SAW.

This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system includes a gas supply system configured to provide a fluorine-containing gas flow. The system also includes a wire supply system configured to provide welding wire, and a flux supply system configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly configured to receive the fluorine-containing gas flow and the welding wire and to deliver the fluorine-containing gas flow and the welding wire near the welding arc during the SAW.

The invention described herein pertains generally to boric acid free flux composition in which boric acid and/or borax is substituted with a molar equivalent amount of potassium tetraborate tetrahydrate. In some embodiments, a phthalocyanine pigment is used to effect a color change at activation temperature.