Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.

[Object] There is provided a flux-cored wire capable of obtaining a weld metal having excellent low temperature toughness and improving welding efficiency, in which preheating performed for preventing cold cracking can be omitted or simplified. [Means for Solving Problems] The flux-cored wire includes one or more of CaF.sub.2, BaF.sub.2, SrF.sub.2, MgF.sub.2, and LiF and, when a total amount thereof is defined as α, the α is 2.0% to 7.0%, by mass %, with respect to a total mass of the flux-cored wire, one or more of a Ti oxide, a Si oxide, a Mg oxide, an Al oxide, a Zr oxide, and a Ca oxide are included in the flux-cored wire, and when a total amount thereof is defined as β, the β is 0.2% to 0.9%, by mass %, with respect to the total mass of the flux-cored wire, a ratio of an amount of the CaF.sub.2 with respect to the α is 0.90 or more, and a ratio of the α with respect to the β is 3.0 or more and 15.0 or less.

The present disclosure relates generally to an improved design of a metal-cored welding wire electrode for use on a high deposition rate welding process that resistively preheats the wire prior to being subjected to the welding current. The preheat circuit reduces the welding current drawn by the electrode so that higher wire feed speeds, and thus higher deposition rates, may be obtained. The metal-cored welding wire includes both a higher fill rate (a greater percentage of the welding wire is the granular core) along with added sulfur and an added bead wetting agent. The bead wetting agent may be one or more of selenium, tellurium, arsenic, gallium, bismuth, and tin. The improved metal-cored welding wire leads to an enhanced weld deposit appearance that means the weld deposits are less likely to be rejected as unusable.

Methods for welding a particle-matrix composite body to another body and repairing particle-matrix composite bodies are disclosed. Additionally, earth-boring tools having a joint that includes an overlapping root portion and a weld groove having a face portion with a first bevel portion and a second bevel portion are disclosed. In some embodiments, a particle-matrix bit body of an earth-boring tool may be repaired by removing a damaged portion, heating the particle-matrix composite bit body, and forming a built-up metallic structure thereon. In other embodiments, a particle-matrix composite body may be welded to a metallic body by forming a joint, heating the particle-matrix composite body, melting a metallic filler material forming a weld bead and cooling the welded particle-matrix composite body, metallic filler material and metallic body at a controlled rate.

The present invention relates to a flux-cored wire which can be used for straight-polarity gas-shielded arc welding, wherein a flux contains one or several types of metal compound powders and, when one or several metal elements constituting the metal compound powders are formed into stable compounds under a high-temperature environment, the relationship between the weighted geometric mean value (Φ) of the work functions of the stable compounds and the wire diameter (D) of the flux-cored wire satisfies the following formula: {1.00≤Φ≤−0.0908D.sup.2+0.5473D+1.547}.

Disclosed is a method for manufacturing an equal-strength steel thin-wall welding component with an aluminum or aluminum-alloy plating, wherein the plating comprises an intermetallic compound alloy layer in contact with the base body and a metal alloy layer on the intermetallic compound alloy layer; the plating is not removed or thinned before or during welding; and by presetting a welding gap and using a carbon-manganese-steel welding wire, a welding process and protective gas for welding, the tensile strength of a welding seam of the welding component after hot stamping processing is greater than the tensile strength of a base metal, and the elongation of a welded joint is greater than 4% Further disclosed are a welding wire for welding and an equal-strength steel thin-wall welding component with an aluminum or aluminum-alloy plating.

A flux-cored wire for arc welding, including a steel sheath filled with flux, where the wire contains, relative to a total mass of the wire, Cr: 16.0 to 22.0 mass %, Ni: 6.0 to 11.0 mass %, Mn: 0.7 to 2.6 mass %, Si: 0.1 to 1.1 mass %, Zr: 0.2 to 0.8 mass %, Fe: 45.0 to 65.0 mass %, TiO.sub.2: 5.0 to 9.0 mass %, SiO.sub.2: 0.1 to 2.0 mass %, ZrO.sub.2: 0.5 to 3.0 mass %, and Bi: less than 0.0020 mass %. Where by mass %, a Si content is denoted by [Si] and a Zr content is denoted by [Zr], a value of parameter A expressed by A=[Si]+2×[Zr] satisfies 1.4 to 2.5.

An automobile undercarriage part of the present invention has a welded joint formed by base steel plate, wherein the chemical composition of a weld metal contains, with respect to a total mass of the weld metal, by mass %, C: 0.02% to 0.30%, Si: 0.10% to less than 1.0%, Mn: 1.2% to 3.0%, Al: 0.002% to 0.30%, Ti: 0.005% to 0.30%, P: more than 0% to 0.015%, and S: more than 0% to 0.030%, the following formula (1A), formula (1B), formula (2), and formula (3) are satisfied, and slag in a toe portion of the fillet weld satisfies a formula (4).

[Al]+[Ti]>0.05  Formula (1A)

[Ti]/[Al]>0.9  Formula(1B)

7×[Si]+7×[Mn]−112×[Ti]−30×[Al]≤12  Formula (2)

2.0<[Si]+[Mn]  Formula (3)

[Ti content on slag surface]>[Si content on slag surface]  Formula (4).

An arc welding method includes welding a steel sheet while alternately switching feeding of a welding wire between forward feeding and backward feeding. The welding wire contains, in mass % with respect to a total mass to the welding wire, C: more than 0 and 0.30 or less, Si: 0.01 to 0.30, Mn: 0.5 to 2.5, S: 0.001 to 0.020, Ti: 0.05 to 0.30, and optional elements with the remainder being Fe and unavoidable impurities, and a value obtained by 2×[Ti]/[Si]−50×[S] is more than 1.0. The welding is performed by using a shielding gas containing CO.sub.2 gas in an amount of 80 vol. % or more with respect to a total volume of the shielding gas at a frequency of 40 Hz or more and 200 Hz or less, where one cycle for determining the frequency is one forward feeding and one backward feeding.

A bond coating material providing unexpectedly high thermal cyclic fatigue resistance and sulfidation resistance, and unexpectedly prolonged thermal cycle life in high temperature environments of gas turbine engine components with and without the presence of sulfur contains: a) 10% to 30% by weight chromium, b) at least one of tantalum and molybdenum in a total amount of 3% to 15% by weight, c) 5% to 13% by weight aluminum, d) 0.1% to 1.4% by weight silicon, e) 0.1% to 0.8% by weight yttrium, f) 0% to 1.2% by weight carbon, g) 0% to 1% by weight dysprosium, h) 0% to 1% by weight cerium, i) the balance being nickel, and the percentages of a) to i) adding up to 100% by weight. The total amount of tantalum and molybdenum, and the amounts of aluminum and silicon are each critical for avoiding delamination of a top coat from a bond coat.