The present invention provides the following: a covered flux which has a low chromium content and which can improve the fatigue strength of a weld in additional welding; and a covered electrode. The covered flux used for a covered electrode has a composition that contains, relative to the total mass of the covered flux, 35-55 mass % of a metal carbonate (in terms of CO2), 10-30 mass % of a metal fluoride (in terms of F), and 8.5-20 mass % of Mn and/or 7.5-20 mass % of Ni. In addition, the covered electrode is obtained by coating an iron-based core wire with this covered flux.

A flux fluid is disclosed for use in manufacturing a heat exchanger (4) by brazing and joining an aluminum tube (3) and an aluminum fin (2). The flux fluid (101) contains a fluoride-based flux, colloidal silica, and a dispersion medium. The mass ratio of the colloidal silica with respect to the fluoride-based flux is 1/200 to 1/15.

The disclosed technology generally relates to welding, and more particularly to a consumable electrode wire for metal arc welding, and a method and a system for metal arc welding using the consumable electrode wire. In one aspect, a consumable welding wire configured to serve as an electrode during metal arc welding comprises one or more alkaline earth metal elements at a concentration between 0.005% and 10% on the basis of a total weight of the welding wire.

A method of fabricating a joining preform includes the step of printing a self-fluxing joining alloy. Joining includes brazing and soldering. The self-fluxing joining alloy contains at least one of phosphorus, boron, fluorine, chlorine, or potassium. Another printing step prints a non-phosphorous joining alloy. Both printing steps are performed by an additive manufacturing or 3D printing process. The printing a self-fluxing joining alloy step may be repeated until the non-phosphorous joining alloy is substantially encapsulated by the self-fluxing joining alloy. The self-fluxing joining alloy may be a BCuP alloy, a CuP alloy, a CuSnP alloy, a CuSnNiP alloy or a CuAgP alloy. The non-phosphorous joining alloy may be a BAg alloy, a BNi alloy or a BAu alloy.

A braze gel includes a braze powder, a braze binder, and a viscosity reducer. The braze gel has a gel viscosity sufficiently low to permit dip coating of a component with the braze gel to apply a braze coating of the braze gel to the component. A brazing process includes applying the braze gel to a portion of a component. The brazing process also includes drying the braze gel to form a braze coating on the component to form a braze-coated component. A brazing article includes a component and a braze coating over a portion of the component. The component may have structural features having a spacing of less than about 5 mm and a depth of at least about 1 mm, which may be honeycomb cells. The component may be a turbine component.

This welded structure comprises a weld metal which contains C, Si, Mn, Cr, Mo, V, Nb, N and O in prescribed amounts respectively with the balance being Fe and unavoidable impurities and which exhibits an A value of 200 or more and a Z value of 0.05 or more. The A value is calculated from the element contents of the weld metal according to the formula: A value=([V]/51+[Nb]/93)/{[V]([Cr]/5+[Mo]/2)}10.sup.4. The Z value is calculated according to the formula: Z value=N[insol. V] [wherein N (particles/m) is the number density of carbide particles present in a prior austenite grain boundary per unit grain boundary in the stress-relief annealed weld metal, and [insol. V] is the concentration of compound-type V as determined by analyzing an extraction residue of the stress-relief annealed weld metal].

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.

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.

The invention described herein pertains generally to a process for making boric acid free flux compositions 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 affect a color change at activation temperature.

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 for joining steel workpieces via arc welding includes a steel sheath disposed around a core. The core includes iron powder, iron titanium powder, silico-manganese powder, iron silicon powder, iron sulfide, graphite, rare earth compound, and a frit. The frit includes a Group I or Group II compound, silicon dioxide, and titanium dioxide. The graphite and the frit together comprise less than 10% of the core by weight.