The present invention accurately distinguishes a soldering material less likely to oxidize. A Cu core ball has a Cu ball having a predetermined size, and a solder layer coating the Cu ball. The Cu ball provides a space between a semiconductor package and a printed circuit board. The Cu core ball has the soldering material having lightness greater than or equal to 62.5 in L*a*b* color space subsequent to a heating storage test performed for 72 hours in a temperature-controlled bath at 150 C. with a temperature of 25 C. and 40% humidity, and the soldering material, prior to the heating storage test, having lightness greater than or equal to 65 in the L*a*b* color space and yellowness less than or equal to 7.0 in the L*a*b* color space.

When a distance between an end portion of a brazing material and a downward extended line of a side surface of an insulating substrate is taken as a, and a distance between an end portion of a solder resist on the side of a solder and the downward extended line of the side surface of the insulating substrate is taken as b, the positional relationship a<b is satisfied. The position of the end portion of the solder is regulated by the solder resist, and the position of the end portion of the brazing material on the side of the side surface of the insulating substrate is closer to the side of the side surface of the insulating substrate than to the position of the end portion of the solder on the side of the side surface of the insulating substrate.

A flux-cored wire for arc welding of a duplex stainless steel includes a stainless-steel sheath filled with a flux and contains, with respect to the total mass of the wire, predetermined amounts of Cr, Ni, Mo, N, Mn, and Si, in which letting a Ti alloy content in terms of Ti be [Ti] and letting an Al alloy content in terms of Al be [Al], [Ti] and [Al] are predetermined values, and in which parameter A expressed as A=[Ti]+2[Al] satisfies a predetermined value, and the balance is composed of Fe, a slag-forming component, and incidental impurities.

A self-shielded flux-cored welding wire with a special protective slag coating formed in situ and a manufacture method thereof. The self-shielded flux-cored welding wire includes a low-carbon steel belt and a flux core powder, the flux core powder is filled in the low-carbon steel belt, the flux core powder includes the following ingredients in percentage by mass: 60-80% glass powder, 2-8% zirconium oxide powder, 0.05-0.85% graphene powder, 2-8% potassium carbonate sodium powder, 1-3% potassium titanate powder, 2-5% rutile powder, 1-5% corundum powder, 1-3% sodium fluorosilicate powder, and the balance of iron powder, and a weight of the flux core powder accounts for 13-25% of a total weight of the welding wire.

There is provided the use of at least one ionic liquid as a soldering/brazing flux. There is also provided a method of soldering a metal comprising applying a solder/braze comprising a flux to a surface of the metal and heating said metal to a desired soldering/brazing temperature, wherein the soldering/brazing flux comprises one or more ionic liquids.

A welding wire for high-strength steel for improving slag coagulation includes a combination of Carbon, Manganese, Silicon, Aluminum, Sulfur, and Selenium. With use of the welding wire, the generation of slag is minimized, and the slag is allowed to induce the generation of crystalline oxides having a low surface energy, so that the slag is easily removed, and the flow of a molten pool to the center in a width direction of a weld bead do that the slag is coagulated.

A welding flux for duplex stainless steel is used to solve the problem of insufficient penetration depth of a weld formed between two jointed workpieces when workpieces with a thickness above 3 mm is joined by TIG welding. The welding flux for duplex stainless steel includes 25-35 wt % of SiO.sub.2, 20-25 wt % of Cr.sub.2O.sub.3, 10-20 wt % of MoO.sub.3, 10-15 wt % of NiO, 5-10 wt % of FeO, 5-10 wt % of Co.sub.3O.sub.4, 5-10 wt % of MnO.sub.2 and 3-5 wt % of CuO.

The disclosed technology generally relates welding wires, and more particularly to coated welding wires. A consumable welding wire comprises a base wire comprising a steel composition and a coating comprising an iron surrounding the base wire, wherein the iron oxide has an oxygen to iron (O/Fe) ratio such that an outer surface of the welding wire has a dark gray to black color.

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 {(3O.sub.2)+CO.sub.2+(0.0085A.sup.2)(0.19A)}20.0 (where A={Cr+(4.3Nb)}).

A conductive paste including (A) a silver powder, (B) a glass frit, (C) an organic binder and (D) a powder containing Cu and at least one metal element selected from the group consisting of V, Cr, Mn, Fe and Co. The powder (D) may thus contain Cu and Mn, Cu and Fe or Cu and Co. The conductive paste has a desirable electromigration resistance, solder heat resistance and adhesiveness to a substrate.